Cardiologist (heart), Otolaryngologists, Surgical Specialist
17 years of experience
Video profile
Greater Knoxville Ear Nose & Throat
1932 Alcoa Hwy, Suite 160
Knoxville, TN 37920
(865) 521-8050
Locations and availability (6)

Education ?

Medical School Score
University of Tennessee (1992)
  • Currently 2 of 4 apples

Affiliations ?

Dr. Baker is affiliated with 14 hospitals.

Hospital Affilations

Score

Rankings

  • St Mary's Medical Center, Inc
    Cardiology
    900 E Oak Hill Ave, Knoxville, TN 37917
    • Currently 4 of 4 crosses
    Top 25%
  • University Of Tennessee Memorial Hospital
    Cardiology
    1924 Alcoa Hwy, Knoxville, TN 37920
    • Currently 4 of 4 crosses
    Top 25%
  • Fort Sanders Regional Medical Center
    Otolaryngology
    1901 W Clinch Ave, Knoxville, TN 37916
    • Currently 3 of 4 crosses
    Top 50%
  • Baptist Hospital Of Cocke County
    Cardiology
    435 2nd St, Newport, TN 37821
    • Currently 3 of 4 crosses
    Top 50%
  • Mercy Medical Center West
    Otolaryngology
    10820 Parkside Dr, Knoxville, TN 37934
    • Currently 2 of 4 crosses
  • North Knoxville Medical Center
  • E Tn Childrens Hosp
  • Ft Sanders Reg Med Ctr
  • Mercy Medical Center North
    7565 Dannaher Way, Powell, TN 37849
  • Ut Med Ctr
  • Mercy Medical Center St. Mary's
    900 E Oak Hill Ave, Knoxville, TN 37917
  • East Tennessee Children's Hospital
    2018 W Clinch Ave, Knoxville, TN 37916
  • University of Tennessee Medical Center
  • Physicians Regional Medical Center
  • Publications & Research

    Dr. Baker has contributed to 54 publications.
    Title Speciation of Cu in a Contaminated Agricultural Soil Measured by Xafs, Micro-xafs, and Micro-xrf.
    Date June 2008
    Journal Environmental Science & Technology
    Excerpt

    Contamination of agricultural soils with Cu as a result of fungicide application and spills threatens environmental quality and reduces soil quality for crop growth. In this paper advanced spectroscopic and microscopic methods were used to elucidate the Cu speciation in a calcareous soil contaminated since the 1940s. Microscopically focused synchrotron-based XRF (micro-SXRF) was used to map the elemental distribution in the soils. Results indicated that most of the Cu was not associated with metal oxides, silicates, phosphates, or carbonates. Bulk and microscopically focused X-absorption near edge structure (XANES) and extended X-ray absorption fine structure (EXAFS) spectra indicated thatthe Cu in the soil was predominantly Cu adsorbed on soil organic matter (SOM). Interpretation of the fitting results suggests that the Cu is complexed to SOM via bidentate inner-sphere coordination with carboxyl or amine ligands. Results presented in this paper provide detailed information on the molecular coordination of Cu in a contaminated soil. Such information is critical for understanding the long-term fate and best management practices for Cu in the environment.

    Title Recruitment and Comfort of Bion Implanted Electrical Stimulation: Implications for Fes Applications.
    Date March 2008
    Journal Ieee Transactions on Neural Systems and Rehabilitation Engineering : a Publication of the Ieee Engineering in Medicine and Biology Society
    Excerpt

    Restoration of motor function to paralyzed limbs by functional electrical stimulation (FES) has been hampered by the lack of precise and gradual control over muscle recruitment. A suitable interface should provide selective stimulation of individual muscles with graded recruitment of force. The BION was developed to enable neuromuscular stimulation through a miniature, self-contained implant designed to be injected in or near muscles and peripheral nerves. In this study, recruitment properties and comfort of the BION implanted electrical stimulation were systematically evaluated in subjects who participated in a clinical trial. Recruitment properties were qualitatively similar to other methods of implanted neuromuscular stimulation: thresholds and steepness of recruitment were negatively correlated and depended on stimulus charge (product of pulse current and duration). Perceived comfort was not affected by the choice of stimulus parameters, thus their choice can be based purely on technical considerations such as efficiency or resolution of recruitment.

    Title Mechanical Loading of Rigid Intramuscular Implants.
    Date January 2008
    Journal Biomedical Microdevices
    Excerpt

    Several groups are developing different versions of a new class of leadless, permanently implanted electronic devices with a size and form factor that allows them to be injected into muscles (BIONs). Their circuitry is protected from body fluids by thin-walled hermetic capsules made from rigid and brittle materials (glass or ceramic) that include feedthroughs to their electrodes. These packages experience repetitive stresses from the very contractions that they excite. We here provide a worst-case analysis of such stresses and methods for testing and validation of devices intended for such usage, along with the failure analysis and remediation strategy for a design that experienced unanticipated failures in vivo.

    Title Rehabilitation of the Arm and Hand Following Stroke--a Clinical Trial with Bions.
    Date September 2007
    Journal Conference Proceedings : ... Annual International Conference of the Ieee Engineering in Medicine and Biology Society. Ieee Engineering in Medicine and Biology Society. Conference
    Excerpt

    This paper reports the clinical experiences and preliminary observations from implanted microstimulators used to reduce some impairments following a stroke. Ongoing research protocols to reduce shoulder subluxation and hand contractures using BION stimulation are described. Comparison of compliance and patient satisfaction between individuals exercising at home with surface stimulation and implanted stimulation are characterized. The effectiveness of the two home based stimulation programs are compared.

    Title Effect of Electrical Stimulation Waveform on Healing of Ulcers in Human Beings with Spinal Cord Injury.
    Date August 2007
    Journal Wound Repair and Regeneration : Official Publication of the Wound Healing Society [and] the European Tissue Repair Society
    Excerpt

    Various electrical stimulation waveforms have been used to enhance wound healing, with little consideration for potential differences in their physiologic effect. The present study evaluated the effect of stimulation waveform and electrode placement on wound healing. Eighty patients with spinal cord injury and one or more pressure ulcers were treated. A total of 185 ulcers received 45 minutes of stimulation daily. Each ulcer was subjected to one of four treatment protocols: asymmetric biphasic waveform, symmetric biphasic waveform, microcurrent stim-ulation, or a sham control protocol. Electrodes were placed outside the wounds, over intact skin and surrounding the area of the ulcer. Data were categorized by ulcers which healed during the protocol and those which did not. Analysis of the "good response" ulcers (n = 104) showed significantly better healing rates for those receiving stimulation with the asymmetric biphasic waveform, compared with the control and microcurrent groups. Mean healing rates from the present study were similar to previously reported measures. The waveforms studied possessed minimal polar capabilities, and the electrodes were placed outside the wound. These data show that electrical stimulation clearly enhanced healing of pressure ulcers in a significant number of individuals with spinal cord injury; the physiologic implications of these findings relative to the mechanism(s) by which electrical stimulation enhances wound healing are discussed. However, extrapolation of these results to patients with other types of wounds must await further study.

    Title Engaging Men and Boys in Preventing Violence Against Women: Applying a Cognitive-behavioral Model.
    Date July 2007
    Journal Violence Against Women
    Excerpt

    Although historically the prevention of relationship violence has been seen as a women's issue, more recently recognition has emerged regarding the need to engage men as partners in these initiatives. Early attempts have been mainly driven by grassroots efforts and have not been consistent with a particular theory of behavior and attitude change. This article investigates the application of cognitive-behavioral strategies to engaging men and boys in violence prevention, within a profeminist framework. Three fundamental components of a cognitive-behavioral therapy approach--goal setting, core beliefs, and strategies for change--are discussed and examples of promising initiatives are used to highlight these ideas.

    Title The Bion Devices: Injectable Interfaces with Peripheral Nerves and Muscles.
    Date June 2006
    Journal Neurosurgical Focus
    Excerpt

    OBJECT: The purpose of this study was to describe a novel technology for implantable neuromuscular stimulation to treat complications of paralysis and disuse atrophy, including shoulder subluxation, hand contractures, drop foot, and osteoarthritis. The authors review the results so far of several pilot clinical studies of these muscle stimulation devices. METHODS: Miniature wireless stimulators received power and individually addressed command signals from an external radiofrequency transmission coil. One or more implants were injected through a 12-gauge hypodermic insertion tool into muscles or adjacent to motor nerves, where they provided the means to activate the muscles in any desired pattern of intensity and frequency. Randomized controlled studies in small numbers of patients are underway to identify efficacy, acceptability, best methods of practice, and any design changes that may be required to improve the technology. Fifty patients have been enrolled in five studies; 35 patients have undergone implantation of a total of 79 BION1 devices. Comparisons with surface stimulation in patients who have suffered a stroke with shoulder subluxation and hand contractures show similar improvements in objective measures of efficacy but higher comfort levels for stimulation by implants. CONCLUSIONS: Injected microstimulators represent a promising new class of technology for the rehabilitation of patients with upper motor neuropathies. As the technology evolves, practitioners may be able to use it to facilitate functional reanimation of paralyzed limbs.

    Title Effect of an Electric Stimulation Facilitation Program on Quadriceps Motor Unit Recruitment After Stroke.
    Date January 2005
    Journal Archives of Physical Medicine and Rehabilitation
    Excerpt

    OBJECTIVE: To compare maximum voluntary isometric torque (MVIT) and motor unit recruitment of the quadriceps after an electric stimulation facilitation program in persons affected by cerebrovascular accident (CVA). DESIGN: Three-week, randomized controlled trial with an electric stimulation facilitation program added to standard care. SETTING: Inpatient rehabilitation center. PARTICIPANTS: Twenty patients receiving rehabilitation for first-time CVA (51.8+/-15.2 y; days post-CVA, 38.4+/-40.0 d). Patients were randomly assigned to study and control groups. INTERVENTIONS: All patients received standard physical therapy (PT) care. In addition, the study group received an electric stimulation facilitation program during weight-bearing and ambulatory activities of the PT program. MAIN OUTCOME MEASURES: MVIT and motor unit recruitment measured by interpolated twitch testing. A 2 x 4 repeated-measures analysis of variance was performed on measurements at 4 intervals: pretest, 1 week, 2 weeks, and 3 weeks. RESULTS: MVIT increased by 77% in patients receiving electric stimulation, compared with a 31% increase for the control group. There was a significant effect for assessment time only. Motor unit recruitment increased from 35% to 53% for the study group, whereas the control group recorded no change in recruitment ability. A significant interaction was recorded, indicating improved motor unit recruitment for the study group. CONCLUSIONS: A brief and dynamic electric stimulation facilitation program significantly improved motor unit recruitment in persons after CVA.

    Title Pediatric Arteriovenous Extracorporeal Membrane Oxygenation (ecmo) As a Bridge to Cardiac Transplantation.
    Date April 2004
    Journal The Journal of Heart and Lung Transplantation : the Official Publication of the International Society for Heart Transplantation
    Excerpt

    BACKGROUND: Since 1990, extracorporeal membrane oxygenation (ECMO) has been used as a bridge to cardiac transplantation in 47 patients. METHODS: A review of the ECMO database, approved by the Arkansas Children's Hospital institutional review board, forms the basis of this report. We made statistical comparison using Fisher's exact probability testing. The ECMO circuitry was a roller occlusion pump with computer-assisted perfusion system technology. RESULTS: Thirty-two (68%) patients underwent transcatheter septostomy for cardiac decompression. Diagnosis at presentation was either congenital heart disease (CHD, n = 15) or cardiomyopathy (n = 32). Ages ranged from 1 day to 22 years old (median, 18 months old), and weight ranged from 2.9 to 100 kg (median, 10 kg). The average duration of support was 242 hours (range, 22-1078 hours). Overall long-term survival was 47%, with 16 (34%) patients successfully bridged to cardiac transplantation (of which 9 [56%] survived) and 13 (28%) successfully weaned from ECMO. Patients undergoing ECMO after cardiotomy had 31% survival. Survival was improved significantly (p < 0.02) in patients with cardiomyopathy (59%) vs those with CHD (20%). Patients with cardiomyopathy underwent 8 transplantations with 7 survivors (88%), whereas in the CHD group, there were 8 transplantations with only 2 survivors (25%), p < 0.05. Sub-analysis of the cardiomyopathy group revealed that patients with acute cardiomyopathy in association with documented viral illness had a 75% chance of being weaned from ECMO without undergoing transplantation. Complications during ECMO occurred in 45% of survivors and were more frequent in non-survivors. Infectious complications were most frequent, followed by neurologic complications, technical ECMO problems, and renal insufficiency. CONCLUSIONS: Patients with cardiomyopathy has a better prognosis than did those with CHD when using ECMO as a bridge to transplantation or survival. Complications are significant and increase with the duration of support. Extracorporeal membrane oxygenation for salvage and subsequent transplantation in this high-risk group of patients requires critical review. Alternative support options must be developed in the pediatric population that will allow improved outcomes, comparable with outcomes achieved in the adult population.

    Title Electromyographic Activity of Selected Trunk Muscles During Dynamic Spine Stabilization Exercises.
    Date December 2001
    Journal Archives of Physical Medicine and Rehabilitation
    Excerpt

    OBJECTIVES: To compare the electromyographic activity of the trunk flexors and extensors during 2 spine stabilization exercises and to evaluate the changes in muscle activity with increasing levels of exercise difficulty. DESIGN: Descriptive study. SETTING: Research laboratory. PARTICIPANTS: Twelve healthy subjects without history of lower back pain. INTERVENTION: Subjects were instructed how to perform the Dying Bug and the Quadruped exercises. Electromyographic and motion data were recorded from each muscle group during maximum voluntary isometric contraction (MVIC). MAIN OUTCOME MEASURES: Surface electromyographic recordings of the erector spinae, rectus abdominus, abdominal oblique, and gluteus maximus muscles. RESULTS: During the Dying Bug exercise, the trunk flexors (rectus abdominus, abdominal oblique) were equally active and demonstrated proportional increases in electromyographic activity with increasing level of exercise difficulty. In the Quadruped exercise, significantly greater electromyographic activity was observed in the abdominal oblique compared with the rectus abdominus; however, abdominal oblique activity did not change with increasing level of difficulty. The erector spinae and gluteus maximus demonstrated a significant level effect and were most active during elevation of the ipsilateral leg. At no point did activity of any of the muscles studied exceed 41% of the MVIC. CONCLUSIONS: Results indicated the Dying Bug exercise predominantly recruited the abdominal musculature, while greater activity was observed in the trunk and hip extensors during the Quadruped exercise. The relatively low levels of electromyographic activity observed in both exercises suggests that the intensity of muscle recruitment is not likely sufficient to provide a strengthening effect in healthy subjects.

    Title Women in Rural General Practice: Conflict and Compromise.
    Date September 2000
    Journal The Medical Journal of Australia
    Title Nasopharyngeal Warthin's Tumor.
    Date June 1999
    Journal Otolaryngology--head and Neck Surgery : Official Journal of American Academy of Otolaryngology-head and Neck Surgery
    Title Effect of Electrical Stimulation on Foot Skin Perfusion in Persons with or at Risk for Diabetic Foot Ulcers.
    Date January 1999
    Journal Wound Repair and Regeneration : Official Publication of the Wound Healing Society [and] the European Tissue Repair Society
    Excerpt

    The failure of foot wounds to heal results in 54,000 people with diabetes having to undergo extremity amputations annually. Therefore, treatment is needed to speed healing in people with diabetes in order to reduce the need for amputation. This study tested the effect of high-voltage pulsed current on foot blood flow in human beings who are at risk for diabetic foot ulcers. Neuropathy, vascular disease, Wagner Class, glucose, gender, ethnicity, and age were measured. A sample of 132 subjects was tested using a repeated-measures design. A baseline transcutaneous oxygen level was obtained; stimulation was applied, and transcutaneous oxygen measurements were recorded at 30- and 60- minute time intervals. The grouped foot transcutaneous oxygen levels decreased (F = 5.66, p =. 0039) following electrical stimulation. Analysis of variance (Scheffe, p <.05) showed that initial transcutaneous oxygen was significantly higher than subsequent readings. However, oxygen response was distributed bimodally: 35 (27%) subjects showed increased transcutaneous oxygen (mean 14.8 mm Hg), and 97 (73%) experienced a decreased transcutaneous oxygen reading (mean 12.2 mm Hg). Logistic regression analysis did not explain these differences. Although this treatment appears to increase blood flow in a subset of patients, further study is needed to identify probable mechanisms for this response.

    Title Effects of Electrical Stimulation on Wound Healing in Patients with Diabetic Ulcers.
    Date June 1997
    Journal Diabetes Care
    Excerpt

    OBJECTIVE: To evaluate the effects of two stimulation waveforms on healing rates in patients with diabetes and open ulcers. The hypothesis was that stimulus waveforms with minimal polar characteristics would provide significant healing for this patient sample. RESEARCH DESIGN AND METHODS: This was a prospective study that enrolled 80 patients with open ulcers. Patients received stimulation with either an asymmetric biphasic (A) or symmetric biphasic (B) square-wave pulse. Amplitudes were set to activate intact peripheral nerves in the skin. Two other groups received either very low levels of stimulation current (MC), or no electrical stimulation (C). When combined these groups were referred to as the control group. Treatment was carried out daily until the wound healed, the patient withdrew from the study, or the physician changed the overall wound management program. Average healing rates were calculated from weekly measures of the wound perimeter and were used for statistical comparison through a one-way analysis of variance. RESULTS: Stimulation with the A protocol significantly increased the healing rate, enhancing healing by nearly 60% over the control rate of healing. Stimulation with the B protocol did not increase the healing rate when compared with control subjects. CONCLUSIONS: Electrical stimulation, given daily with a short pulsed, asymmetric biphasic waveform, was effective for enhancement of healing rates for patients with diabetes and open ulcers.

    Title Atlanto-axial Subluxation and Cervical Osteomyelitis: Two Unusual Complications of Adenoidectomy.
    Date May 1996
    Journal The Annals of Otology, Rhinology, and Laryngology
    Excerpt

    Grisel's syndrome (atlanto-axial subluxation) and cervical osteomyelitis are two unusual complications of adenoidectomy. We present two patients; one with atlanto-axial subluxation following uncomplicated tonsillectomy and adenoidectomy, and one with cervical osteomyelitis following uncomplicated adenoidectomy. Both patients presented with persistent postoperative neck pain. Surgical intervention, as well as long-term intravenous antibiotics, was required. A high index of suspicion, as well as cervical spinal series with flexion-extension views, is necessary for diagnosis. Flexible nasopharyngoscopy and computed tomography of the cervical spine also aided in diagnosis and treatment planning. With early diagnosis and proper treatment, the prognosis is good. Neurologic sequelae were prevented in both of our patients.

    Title Inter-hospital Transport of Neonatal Patients on Extracorporeal Membrane Oxygenation: Mobile-ecmo.
    Date May 1995
    Journal Pediatrics
    Excerpt

    OBJECTIVE. To describe the equipment, personnel requirements, training, management techniques, and logistic problems encountered in the design and implementation of a mobile extracorporeal membrane oxygenation (ECMO) program. DESIGN. This is a report of a technique for the transport of patients on ECMO and a description of our retrospective case series. SETTINGS. The study was conducted at a regional referral children's hospital and ECMO unit. PATIENTS. Thirteen neonatal medical patients with acute respiratory failure were transported with mobile-ECMO. RESULTS. Over a 24-month period, we transported 13 neonatal patients with mobile-ECMO. The reason for transport with mobile-ECMO was inability to convert from high-frequency ventilation (4 of 13), patient already on ECMO (1 of 13), and patient deemed too unstable for conventional transport (8 of 13). Eleven of the 13 patients were transported from other ECMO centers. Of the 13, 9 survived. No major complications during transport were reported for any of the patients. Follow-up data were available on all nine survivors of neonatal mobile-ECMO. Eight of these had normal magnetic resonance imaging scans of the brain; the ninth had a small hemorrhage in the left cerebellum. CONCLUSION. Our limited series shows that patients can be safely transported with mobile-ECMO. This program does not replace the early appropriate transfer for ECMO-eligible patients to an ECMO center.

    Title Cerebrovascular Disease.
    Date December 1993
    Journal Current Opinion in Neurology and Neurosurgery
    Excerpt

    The recent literature addresses the early detection of cerebrovascular disease using imaging techniques, metabolic assessment using spectroscopy, developments in quantitative analysis of brain blood flow, and new interventional techniques for aneurysm obliteration and carotid angioplasty.

    Title Mobile Extracorporeal Membrane Oxygenation.
    Date June 1993
    Journal The Annals of Thoracic Surgery
    Excerpt

    Transport of critically ill neonates in need of extracorporeal membrane oxygenation can be risky. Their extreme cardiorespiratory instability may delay or even preclude conventional transport to an extracorporeal membrane oxygenation center. We report the use of a UH-1 helicopter specially adapted for mobile extracorporeal membrane oxygenation support to transport a critically ill neonate.

    Title Trouble Shooting the Extracorporeal Membrane Oxygenator Circuit and Patient.
    Date May 1993
    Journal The Journal of Extra-corporeal Technology
    Excerpt

    Patients requiring extracorporeal membrane oxygenation (ECMO) often become totally dependent on the mechanical life support. The Extracorporeal Life Support Organization (ELSO) reports 2486 incidents of mechanical complications in 5905 ECMO supports. To help decrease the number of mechanical complications, an active quality assurance program was initiated at our institution. This resulted in identification of only 14 incidents of mechanical complications in 100 patients (neonate, pediatric, adult, and cardiac). Techniques for dealing with problems such as loss of roller pump occlusion, changing out of the membrane lung or heat exchanger without interrupting ECMO support, venous air lock, tamponade, emergency transfusion, and other situations were generated into written policies and procedures. We routinely review and practice problem solving techniques with specific emphasis on monitoring patient hemodynamics and appearance. We conclude that written policies and procedures, "water drills," and continuing education can be beneficial in early recognition, intervention, and/or prevention of ECMO mechanical complications.

    Title Hemangiomas and Vascular Malformations of the Head and Neck: Mr Characterization.
    Date April 1993
    Journal Ajnr. American Journal of Neuroradiology
    Excerpt

    PURPOSE: To characterize the MR appearance of the common hemangioma of infancy as well as low- and high-flow vascular malformations of the head and neck. PATIENTS AND METHODS: Twenty patients with vascular lesions of the head and neck proved either by pathology, angiography, and/or unequivocal clinical diagnosis were included. Vascular lesions included 15 low-flow lesions (four hemangiomas, 10 venous malformations, one lymphatic malformation), and five high-flow lesions (three arteriovenous malformations (AVMs) and two invasive combined malformations). All patients had MR studies (generally 1.5 T using routine T1- and T2-weighted spin-echo sequences). Nine had postgadolinium, gradient recalled-echo, CT, and/or angiographic studies. FINDINGS: Deep hemangiomas and venous malformations demonstrate intermediate signal in T1-weighted images, heterogeneous high signal on T2-weighted images, and prominent enhancement. Involuting hemangiomas show focal areas of high signal intensity on T1-weighted images due to fatty replacement. Venous malformations may demonstrate venous lakes seen as homogeneous regions of high signal intensity on T2-weighted images and phleboliths seen as low signal foci. The one patient with lymphatic malformation showed a large multicystic submandibular mass with large hemorrhage-fluid levels. Features of high-flow lesions (AVMs) include serpiginous signal voids, absence of a dominant mass, and intraosseous extension with decreased marrow signal on T1-weighted images. Invasive combined vascular malformations showed serpiginous flow voids and infiltrative solid masses. Low-flow lesions (hemangiomas, venous, and lymphatic malformations) demonstrate distinct MR findings allowing their differentiation from high-flow lesions (AVMs). Deep hemangiomas and venous malformations appear as solid masses and may look identical. Venous lakes and phleboliths are features of venous malformations which, when present, may help in diagnosis. Combined vascular malformations share features of both low- and high-flow malformations. CONCLUSION: MR is useful in delineating the extent of disease and differentiating low- and high-flow vascular lesions.

    Title The Large Temporal Horn: Mr Analysis in Developmental Brain Anomalies Versus Hydrocephalus.
    Date June 1992
    Journal Ajnr. American Journal of Neuroradiology
    Excerpt

    PURPOSE: To utilize MR to delineate the morphologic abnormalities of the temporal horn and adjacent structures in patients with congenital brain anomalies and to differentiate these findings from the temporal horn alterations in obstructive hydrocephalus. PATIENTS AND METHODS: Thirty-six patients were included in this retrospective study, including eight with agenesis of the corpus callosum (ACC), four with lissencephaly (lis), four with lobar holoprosencephaly (holo), as well as 20 with isolated obstructive hydrocephalus due to tumor (17 patients) or aqueductal stenosis (three patients). Twenty patients with normal scans were included as controls. RESULTS: Coronal plane image analysis showed that 75% of patients with brain anomalies had enlargement of the temporal horns, most prominently involving the inferolateral aspects of the ventricle (8/8 ACC, 4/4 lis, 0/4 holo). Hippocampal formations were small in 62% (6/8 ACC, 3/4 lis, 1/4 holo). An abnormal, vertical orientation (incomplete inversion) of the hippocampal formations was observed in 82% (8/8 ACC, 4/4 lis, 1/4 holo). Focal thinning of the white matter lateral to the temporal horn was seen in 50% (8/8 ACC, 0/4 lis, 0/4 holo). All patients with isolated obstructive hydrocephalus showed enlargement of the temporal horns, most pronounced in the superior-lateral region. Hippocampal formations showed normal, horizontal orientation (complete inversion) and were of normal size in 17 of 20 patients; the only exceptions included patients with severe hydrocephalus where the hippocampi were flattened along the inferior margin of the temporal horn. Temporal lobe white matter was normal in the 17 patients with mild or moderate hydrocephalus: diffuse white matter thinning inferolaterally was observed in the three patients with severe hydrocephalus. Distinct differences were present in the morphology of the temporal horn and surrounding brain in congenital brain disorders compared with those in patients with hydrocephalic. The anomalous brains showed enlargement as a result of incomplete development, and the hydrocephalic brains showed enlargement as a result of increased intraventricular pressure. CONCLUSION: Temporal horn enlargement in lissencephaly and agenesis of the corpus callosum should not be misinterpreted as hydrocephalus. Analysis of temporal lobe morphology will allow differentiation if doubt exists.

    Title Recent Advances in Mr Imaging/spectroscopy of Cerebral Ischemia.
    Date June 1991
    Journal Ajr. American Journal of Roentgenology
    Excerpt

    Recent advances in high-resolution MR imaging and multinuclear spectroscopy have stimulated studies of the functional relationships between tissue hypoperfusion, cellular energy depletion, and brain edema associated with cerebral ischemia. The very slow (microns/sec) random translational motion of water protons in various brain tissues and intracranial fluid compartments can now be assessed with MR diffusion imaging. More slowly diffusing protons in ischemic tissues can be differentiated from normal parenchyma, CSF, and flowing blood, enabling the detection and localization of ischemic regions within minutes of the onset of stroke. Perfusion imaging "snapshots," obtained in as little as 25 msec with echoplanar MR methods, permit the evaluation of tissue washin/washout kinetics of contrast agents in the microvasculature, and thus the quantification of brain perfusion on a regional basis. Also, delineation of major intra- and extracranial arterial and venous structures with MR angiography, acquired with two- or three-dimensional Fourier transformation techniques, has enabled accurate noninvasive assessments of vascular occlusive disease. Finally, improvements in MR spectroscopic techniques have facilitated investigations of metabolic regulation and bioenergetics in experimental animal models of cerebral ischemia, as well as in stroke patients. Combined MR imaging and spectroscopy will likely play an important role in differentiating reversibly from irreversibly ischemic brain tissues and in the investigation of various neuroprotective pharmaceuticals.

    Title Sonographic Detection of Congenital Pancreatic Cysts in the Newborn: Report of a Case and Review of the Literature.
    Date October 1990
    Journal Pediatric Radiology
    Excerpt

    A case of congenital pancreatic cysts detected antenatally by ultrasound is presented. This is the second case detected antenatally. Congenital pancreatic cysts should be included in the differential diagnosis of upper abdominal cystic masses in the fetus and newborn infant.

    Title Staging of Hodgkin Disease in Children: Comparison of Ct and Lymphography with Laparotomy.
    Date June 1990
    Journal Ajr. American Journal of Roentgenology
    Excerpt

    Proper therapy for Hodgkin disease requires accurate staging of the disease. We compared the value of CT and lymphography with that of laparotomy for staging newly diagnosed Hodgkin disease in 46 children. The laparotomy revealed disease in one or more subdiaphragmatic sites in 46%. Correlation of the imaging studies with the laparotomy findings showed that lymphography has a greater sensitivity (80%) than does CT (40%) in detecting retroperitoneal lymph nodes. The sensitivity of CT in detecting splenic involvement was only 19%, presumably because of the small size of tumor deposits in involved spleens. Staging laparotomy altered the clinical stage in 37% of children, which resulted in a significant change of therapy in those patients. Although lymphography and, to a lesser degree, CT are useful for staging of Hodgkin disease, laparotomy continues to be the most important tool in choosing appropriate therapy for children with Hodgkin disease.

    Title Structure-activity Relationships for Osteolathyrism. Iii. Substituted Thiosemicarbazides.
    Date June 1990
    Journal Journal of Applied Toxicology : Jat
    Excerpt

    Eight substituted thiosemicarbazides were assayed for their toxicity and teratogenicity using early embryos of Xenopus laevis. Results of the 96-h static tests on seven 4-position alkyl substituents were used for quantitative structure-activity relationship (QSAR) analyses, with thiosemicarbazide as the parent compound. The compounds induced malformations via the connective tissue defect osteolathyrism. Teratogenicity (log EC50) was negatively correlated with molar refractivity, suggesting that steric inhibitions were important in explaining the variations in biological activity due to changes in the 4-position substituent. It appeared that there were two separate modes of lethal action, one associated with the ring-containing substituents and the other with straight-chain substituents. However, QSARs were not developed for embryolethality (log LC50) or for the mortality/malformation index (LC50/EC50) due to the limited number of chemicals eliciting each lethal mode of action.

    Title Benign Versus Pathologic Compression Fractures of Vertebral Bodies: Assessment with Conventional Spin-echo, Chemical-shift, and Stir Mr Imaging.
    Date February 1990
    Journal Radiology
    Excerpt

    Differentiation of benign from pathologic compression fractures of vertebral bodies was evaluated with magnetic resonance imaging in a prospective study of 53 patients. Twenty-six patients had 34 benign posttraumatic compression fractures. Twenty-seven patients had metastatic disease to the vertebral column and seven pathologic fractures. T1- and T2-weighted spin-echo (SE) sequences (1.5 T) were performed in all patients. A presaturation technique was used to obtain "fat" and "water" images to better assess the degree of normal fatty marrow replacement in fractured vertebrae. Short inversion-time inversion-recovery (STIR) images were also obtained. Discrimination between benign and pathologic compression fractures was generally possible with the SE sequences. Chronic benign fractures demonstrated isointense marrow signal intensity (SI), compared with that of normal vertebrae with all sequences. Pathologic fractures showed low SI on T1-weighted images and high SI on T2-weighted images. Fat images revealed complete replacement of normal fatty marrow, shown as absent SI in the involved vertebral body. Water and STIR images showed diffuse high SI in pathologic fractures, with STIR images having the highest contrast between abnormal and normal marrow. Acute benign compression fractures also demonstrated high SI on T2-weighted, water, and STIR images, but the SI was less pronounced and the pattern was generally more inhomogeneous than that of pathologic compressions. In general, fat images showed only partial replacement of normal fatty marrow by low SI, in contrast to the complete absence of marrow SI typical of pathologic fractures.

    Title Structure-activity Relationships for Di and Tri Alkyl And/or Halogen Substituted Phenols.
    Date October 1989
    Journal Bulletin of Environmental Contamination and Toxicology
    Title Recruitment Data for Nerve Cuff Electrodes: Implications for Design of Implantable Stimulators.
    Date April 1989
    Journal Ieee Transactions on Bio-medical Engineering
    Excerpt

    Recruitment characteristics of nerve cuff electrodes implanted in four cats for five months were measured. Monopolar, bipolar, and tripolar configurations were considered. Approximately twice the current was required to achieve a given response using the tripolar configuration as compared with monopolar stimulation. Bipolar stimulation also required more current than monopolar stimulation. Using the recruitment data, a number of strategies for modulating muscle tension were considered. It was shown that both pulse amplitude and pulse duration should be software-selectable to achieve adequate control of muscle tension when using either pulse amplitude modulation or pulse duration modulation. When using pulse amplitude modulation, it was found to be desirable to operate at a low pulse duration in the high end of the allowable range for pulse amplitude. For pulse duration modulation, one should operate at a low pulse amplitude in the high end of the allowable range for pulse duration. The effect of pulse amplitude and pulse duration step size on the maximum step change in muscle tension and the linearity of the recruitment curves were examined. The use of logarithmic steps in the modulation parameter was examined and was shown to result in improved controllability and linearity.

    Title Effects of Waveform on Comfort During Neuromuscular Electrical Stimulation.
    Date September 1988
    Journal Clinical Orthopaedics and Related Research
    Excerpt

    Electrical stimulation is a commonly used clinical tool, but subject and patient comfort is still a major problem retarding its widespread application. Stimulus waveform in combination with pulse duration can play a major part in subject comfort. An asymmetric balanced biphasic square waveform was perceived as comfortable and was clinically effective in stimulating wrist flexor and extensor muscles. Subjects preferred the square waveforms over a paired spike monophasic waveform. In the larger quadriceps muscle group, a symmetric biphasic square wave was perceived as more comfortable than either a monophasic paired spike or any of three medium frequency waveforms. There seemed to be, however, a small subpopulation of subjects who consistently preferred the medium frequency waveforms. Medium frequency stimulation should be tried for those patients who have considerable difficulty adapting to the sensory input inherent with the use of surface electrical stimulation.

    Title End-stage Periventricular Leukomalacia: Mr Evaluation.
    Date September 1988
    Journal Radiology
    Excerpt

    A prospective study was performed to assess the capabilities of magnetic resonance (MR) imaging in evaluation of end-stage periventricular leukomalacia (PVL) in six children, aged 31-54 months, in whom PVL had been documented by neurologic ultrasonography during the neonatal period. Eight children of similar age (four premature infants and four full-term infants) with normal neurologic development served as controls. A characteristic triad of PVL abnormalities was seen on MR images: (a) abnormally increased periventricular white-matter signal intensity on the first and second echo images of a T2-weighted sequence (repetition time = 2,000-2,400 msec, echo times = 20 or 30 and 80 msec), most commonly observed in the trigone regions of the lateral ventricles bilaterally; (b) marked loss of periventricular white matter in these regions of abnormal signal intensity, predominantly in the periatrial regions; and (c) compensatory focal ventricular enlargement adjacent to regions of abnormal signal intensity. In patients with the classic periatrial distribution of PVL lesions, general correlation between the degree of neurologic impairment and the severity of MR abnormalities was demonstrated. MR imaging was useful in detecting subtle forms of PVL in cases in which neurologic damage was subclinical.

    Title Effects of Joint Angle, Electrodes and Waveform on Electrical Stimulation of the Quadriceps and Hamstrings.
    Date August 1988
    Journal Annals of Biomedical Engineering
    Excerpt

    Isometric twitch moments of the quadriceps and hamstrings were recorded in 20 normal subjects at 40 cells of a superimposed grid. Results were compared at 15, 45, and 75 degrees of knee flexion. Bipolar stimulation at 6 pairs of cells was performed to determine the effect of electrode size, waveform, and polarity on moments. The quadriceps had one region of excitability over the femoral nerve and a second broader region of excitability over the muscle mass. Neither location was significantly affected by knee flexion. Regions of excitability for the hamstrings demonstrated more individual variation and were affected by knee angle. Electrode size had little effect on moments produced with monopolar or bipolar stimulation. When monophasic waveforms were used, reversing polarity generally caused changes in moments of greater than 20%, whereas polarity had no significant effect when using biphasic waveforms. Moments produced with biphasic waveforms were always greater (by 20-25%) when compared with monophasic waveforms. During monopolar, monophasic stimulation, the anode, often termed the "indifferent" electrode, produced nearly 70% of the moment produced by the cathode.

    Title Mr Imaging of Brain Contusions: a Comparative Study with Ct.
    Date May 1988
    Journal Ajr. American Journal of Roentgenology
    Excerpt

    Ninety-eight brain contusions in 17 patients served as a data base for a comparative study of MR and CT for defining brain contusions. MR was the more sensitive technique, detecting 98% of the brain contusions compared with only 56% by CT. CT was slightly better for showing hemorrhagic components, documenting 77% of hemorrhages compared with 71% for MR. The appearance of the contusions on MR was variable, depending on the T1- and T2-weighting of the images and the constituents of the contusions, such as edema, hemorrhage, and encephalomalacia. On MR, hemorrhagic components appeared as high signal on T1-weighted images and as either low or high signal on T2-weighted images, depending on the age of the hemorrhage. The approximate ages of hemorrhagic contusions were often suggested by their appearance on T1- and T2-weighted images. CT is very effective for evaluating acute head trauma, but MR is recommended for documenting brain contusions during the subacute and chronic stages of head injuries.

    Title The High Signal Intensity Meniscus of the Knee. Magnetic Resonance Evaluation and in Vivo Correlation.
    Date March 1988
    Journal Investigative Radiology
    Excerpt

    This study describes the different appearances of meniscal abnormalities on magnetic resonance (MR) images and correlates macroscopic and histologic findings. Twenty-three of 40 cadaveric menisci with MR signal abnormalities were examined macroscopically; five of the 23 were studied histologically. In addition, MR studies of seven patients (14 menisci) were examined and findings were correlated arthroscopically. Histologic analysis was performed on two of these menisci. The two major findings on MR images were: (1) abnormal, high, centrally located signal intensity within the meniscus and (2) disruption of the peripheral meniscal contour. Macroscopically evident meniscal degeneration correlated well with findings on MR images in all cases. Histologic abnormalities included microcyst formation and separation of collagen bundles. Four menisci with intact outer contour lines on MR images had macroscopically identifiable tears. In addition, two meniscal tears were appreciated only after intra-articular injection of gadolinium-DTPA. We conclude that MR imaging is superior to macroscopic examination as performed by arthroscopy or arthrotomy for the detection of degenerative meniscal lesions. The technique also accurately identifies meniscal tears, a capability that might be enhanced by prior intra-articular injection of MR contrast agents.

    Title Characterization of Hindlimb Motoneuron Membrane Properties in Acute and Chronic Spinal Cats.
    Date December 1987
    Journal Brain Research
    Excerpt

    The purpose of this study was to determine if changes in hindlimb motoneuron membrane electrical properties occur 4-6 months after spinal transection in the adult animal. Eight acute and nine chronic animals were spinalized at T12. Intracellular recordings from motoneurons innervating the triceps surae were performed. Membrane electrical properties, including resting potential, action potential peak amplitude, afterhyperpolarization duration, rheobasic current, input resistance and axonal conduction velocity were measured. There were no statistical differences found between group means or frequency distributions in the membrane properties of motoneurons assessed from acute and chronic spinal animals. Thus, alteration of motoneuron membrane properties does not appear to be a major contributing factor to the hyperexcitable hindlimb reflex activity demonstrated by chronic spinal animals.

    Title Characterization of Postsynaptic Potentials Evoked by Sural Nerve Stimulation in Hindlimb Motoneurons from Acute and Chronic Spinal Cats.
    Date December 1987
    Journal Brain Research
    Excerpt

    The purpose of this study was to characterize the changes in postsynaptic potentials recorded in ankle extensor motoneurons resulting from activation of the sural nerve after spinal cord transection in the adult cat. Eight acute and nine chronic animals were spinalized at T12. Intracellular recordings from motoneurons innervating the triceps surae were performed. Sural nerve stimulation evoked complex synaptic potentials consisting of early and late components in all motoneurons. Early excitatory and inhibitory postsynaptic potentials (PSPs), as well as long latency excitatory postsynaptic potentials were recorded and averaged for assessment of PSP amplitude and duration. Early PSPs, both excitatory and inhibitory, were significantly larger in the motoneurons of cats spinalized 4-6 months earlier. Central latency of excitatory potentials were similar in the two samples of motoneurons, but the central latency associated with the initial inhibitory PSP was significantly shorter in the recordings from motoneurons of chronic spinal cats. In most recordings, an additional inhibitory PSP followed the initial excitatory PSP in motoneurons, and this secondary inhibitory PSP was similar in peak amplitude and duration in both samples of motoneurons. Also, a long latency excitatory PSP was recorded in a large percentage of motoneurons from both samples. This potential was typically of greater amplitude and longer duration in the motoneurons from chronic animals, when compared to recordings from acute animals. Although changes in amplitude and duration of PSP activity could be documented, there was no marked alteration in the frequency of occurrence of each PSP pattern recorded from the two preparations. This suggests that the synaptic pathways mediating the sural nerve reflexes have not qualitatively changed in the chronic spinal animal. The changes in amplitudes and durations of the PSPs in the chronic spinal cat indicate, however, that quantitative changes have occurred. The quantitative changes have probably occurred in the interneuronal networks activated by cutaneous nerve (sural) stimulation, since it was shown that only minor changes in motoneuron membrane properties could be recorded in these same chronic spinal animals.

    Title Magnetic Resonance Imaging of the Lumbar Spinous Processes and Adjacent Soft Tissues: Normal and Pathologic Appearances.
    Date November 1987
    Journal The Journal of Rheumatology
    Excerpt

    The spinous processes and intervening soft tissues of the lumbar region may be involved by degenerative, inflammatory, neoplastic, and traumatic processes resulting in low back pain. While conventional radiography and computed tomography have proven useful in the demonstration of abnormalities affecting the spinous processes, they are of limited utility in the evaluation of the intervening soft tissues, which are the predominant site of initial pathologic involvement. To explore the potential role of magnetic resonance imaging (MRI) in the assessment of the spinous processes and adjacent ligaments, a retrospective review of 55 consecutive examinations of the lumbar spine was performed. The normal and pathologic appearances of the region on both T1 and T2 weighted images were characterized, and the optimal imaging variables for demonstration of the spinous processes and adjacent soft tissues were determined with subsequent prospective application to new cases. Correlative examination of cadaveric sections and dried specimens was also performed to facilitate understanding of anatomical relationships visualized by MRI. Based upon the results of this investigation, MRI is the procedure of choice in the evaluation of disease processes affecting the spinous processes and intervening ligaments, primarily owing to the ability to image directly in the sagittal plane and its superior soft tissue contrast discrimination capability.

    Title Magnetic Resonance Imaging of Glenohumeral Joint Diseases.
    Date September 1987
    Journal Skeletal Radiology
    Excerpt

    Through the application of oblique planes and flexible surface coil techniques, magnetic resonance imaging (MRI) promises to be of great clinical value in the evaluation of a variety of pathologic conditions affecting the shoulder. In patients with joint effusions, the tendinous portion of the rotator cuff, glenoid labrum, and bicipital tendon can be readily visualized. This capability has particular relevance in patients with inflammatory disease and traumatic conditions. Rotator cuff atrophy and impingement of the coracoacromial arc upon the supraspinatus muscle and tendon can also be demonstrated. MRI is also useful in the evaluation of shoulder instability.

    Title Perfluorochemicals As Gastrointestinal Contrast Agents for Mr Imaging: Preliminary Studies in Rats and Humans.
    Date June 1987
    Journal Ajr. American Journal of Roentgenology
    Excerpt

    The ability to distinguish bowel from other intraabdominal structures is essential for the accurate diagnosis of intraabdominal disease with MR. Because perfluorochemicals have no protons, they cause no MR signal. Since they are immiscible with water, they create a signal void in bowel independent of bowel contents and thus are suitable as oral contrast agents. Furthermore, they are tasteless and odorless and have no side effects. We evaluated the use of perfluorochemicals by performing MR scans of the abdomen in rats after the oral administration of unemulsified perfluorohexylbromide or perfluoroctylbromide. Since the latter is approved as an investigational drug for oral use in humans, two volunteers were also studied. Both compounds created signal void in the bowel of both rats and human subjects allowing identification of the gastrointestinal tract. The results suggest that these compounds have potential as oral contrast agents for MR imaging.

    Title High-resolution Magnetic Resonance Imaging of the Wrist: Normal Anatomy.
    Date May 1987
    Journal Skeletal Radiology
    Excerpt

    Magnetic resonance imaging (MRI) provided adequate depiction of carpal soft tissue structures in normal volunteers, as well as accurate anatomic correlation with cadaveric specimens. Using a high field strength system and surface coil techniques, the intricate anatomy of the wrist was best defined on long TR short TE images. However, from a practical view, T1 weighted images (TR 600 ms, TE 25 ms) were most useful because of short imaging times, satisfactory image quality, and the absence of motion artifacts. The coronal plane provided the clearest definition of important structures. Potential diagnostic limitations exist due to the inability of MRI to clearly delineate articular cartilage, joint capsules, and small interosseous ligaments. The presence of intra-articular fluid in both living subjects and cadaveric specimens, however, allowed for fine depiction of these structures on T2 weighted images.

    Title Mr Arthrography: Anatomic-pathologic Investigation.
    Date April 1987
    Journal Radiology
    Excerpt

    To enhance the efficacy of magnetic resonance (MR) imaging in evaluating articular soft-tissue structures, arthrography was performed before imaging 45 fresh cadaveric specimens. Contrast agents used were gadolinium-DTPA, 0.9% saline, diatrizoate, and air. MR imaging was performed with and without intraarticular contrast material, and specimens were subsequently sectioned in the same plane. Gd-DTPA was the most effective agent. Saline and diatrizoate exhibited equivalent signal behavior and necessitated T2-weighted sequences, while air was not useful. Depiction of normal anatomy was enhanced with MR arthrography. After surgical creation of lesions in selected specimens, subtle tears were delineated exclusively with MR arthrography, and major tears were diagnosed more confidently. Intraarticular contrast material may enhance the diagnostic capabilities of MR imaging in the setting of joint disease.

    Title Mr Imaging of the Scrotum: Normal Anatomy.
    Date April 1987
    Journal Radiology
    Excerpt

    High-resolution magnetic resonance (MR) imaging with a surface coil was utilized to evaluate the normal scrotum. Scrotal contents, spermatic canal, and inguinal regions were visualized within the same field of view. Differences in signal intensity in the testis, epididymis, tunica albuginea, fluid, fat, and spermatic cord allowed for clear delineation of these structures in detail. The high contrast and spatial resolution of MR imaging, coupled with the wide field of view and absence of ionizing radiation, make MR imaging well suited for evaluation of the scrotum.

    Title Mr Imaging of the Scrotum: Pathologic Conditions.
    Date April 1987
    Journal Radiology
    Excerpt

    The utility of high-resolution magnetic resonance (MR) imaging in studying a variety of intratesticular and extratesticular pathologic conditions was assessed. The high magnetic signal intensity of the testis provided an excellent background for visualization of intratesticular abnormalities. Except for old blood, all intratesticular processes were less intense than testis, especially on T2-weighted images. The visualization of the tunica albuginea is a distinct advantage, allowing its assessment in cases of trauma or testicular tumors. Epididymal and spermatic cord abnormalities were easily recognized. All pathologic conditions were best seen on T2-weighted images acquired in the coronal plane. Balanced images allowed for tissue characterization.

    Title Polyorchidism: Evaluation by Mr.
    Date February 1987
    Journal Ajr. American Journal of Roentgenology
    Title Focal Fat Deposition in Axial Bone Marrow: Mr Characteristics.
    Date January 1987
    Journal Radiology
    Excerpt

    One hundred fifty-eight magnetic resonance (MR) imaging studies of the spine were reviewed to assess the frequency and distribution of focal deposits with signal behavior typical of fat in the axial bone marrow. In addition, three fresh cadaveric spines were evaluated with MR imaging and subsequently sectioned for anatomic and histologic correlation. Macroscopic evaluation of the sectioned cadaveric specimens revealed well-defined, yellow areas within the bone marrow that correlated precisely with localized zones of signal intensity characteristic of fat on MR images. Histologic evaluation of these regions demonstrated typical focal fatty replacement of hematopoietic bone marrow. Their appearance was related to age and the presence of pathologic changes such as spondylitis, kyphoscoliosis, and spondylosis. Based upon these observations, focal fatty replacement of hematopoietic bone marrow appears to be a common phenomenon that should not be confused with localized disease processes.

    Title Neuromuscular Electrical Stimulation of the Muscles Surrounding the Shoulder.
    Date January 1987
    Journal Physical Therapy
    Excerpt

    Neuromuscular electrical stimulation (NMES) can be used to augment range-of-motion, strengthening, and facilitation treatment programs of the muscles surrounding the shoulder. The purposes of this article are 1) to describe the uses of NMES around the shoulder joint as developed through our clinical use and 2) to detail the effects of an NMES program on chronic shoulder subluxation as determined by a clinical study. Because of the complexities of this multiarticular joint, NMES is most useful in the initial phase of the ROM, and stimulated contractions are compromised, relatively, as the humerus moves above the 90-degree horizontal plane. The use of NMES to provide scapular stabilization often entails unwanted alteration of the pressures on the spinal column, occasionally making the treatment program unusable. Electrical stimulation to prevent or correct shoulder subluxation, especially in the neurologically involved patient, provides the therapist with a powerful new treatment technique. In a group of stroke patients, shoulder subluxation was reduced significantly (p less than .05) at the completion of a six-week NMES program. Some of the problems, and possible solutions, unique to the development of electrical stimulation programs for the shoulder muscles are discussed.

    Title High-resolution Magnetic Resonance Imaging of the Ankle: Normal Anatomy.
    Date December 1986
    Journal Skeletal Radiology
    Excerpt

    An imaging-anatomic correlative study of ankle anatomy based upon six healthy adults and six fresh cadaveric specimens was performed to evaluate the diagnostic capabilities of magnetic resonance imaging (MRI). Optimal pulsing sequences and imaging planes for various structures of interest were established. MRI afforded exquisite depiction of anatomic detail, particularly the diagnostically important collateral ligaments. Limitations in the ability to delineate the joint capsule and articular cartilage were documented, with the former detectable only on T2 weighted images in the presence of synovial fluid.

    Title High- and Low-density Lipoprotein Cholesterol: Correlates in an Older Population.
    Date November 1985
    Journal Preventive Medicine
    Excerpt

    A predominantly upper-middle-class white population of 279 men and 345 women with an average age of 66 years was evaluated to determine correlates of high- and low-density lipoprotein cholesterol (HDL and LDL), since these may be the only cholesterol measurements predictive of cardiovascular disease after age 50. Associations of HDL and LDL with age, alcohol use, obesity, smoking, diet, exercise, and medication use were examined using multiple linear regression. Alcohol, average and above-average exercise, postmenopausal estrogen use (women), B vitamin intake, and corticosteroid use were all positively related to HDL levels, and obesity (men only), cigarette smoking, and thyroid hormone use were inversely related. The only statistically significant correlates of LDL were an increase with age (women only) and lower levels in women using thyroid hormone. However, the associations of several behavioral variables with LDL, although not statistically significant, were in the expected direction. These results may suggest the continuing potential for preventive intervention even in an elderly population.

    Title Effects of Waveform Parameters on Comfort During Transcutaneous Neuromuscular Electrical Stimulation.
    Date July 1985
    Journal Annals of Biomedical Engineering
    Excerpt

    Twenty-three females between the ages of 19 and 35 were studied in order to compare the effects of variations in pulse duration, waveform symmetry, and source regulation on comfort during quadriceps surface stimulation at amplitudes necessary to produce 27 Nm torque. Stimulation parameters compared were: 1) 50 and 300 microseconds pulse durations, 2) asymmetrical and symmetrical biphasic waveforms, and 3) current and voltage source regulation. Subjects overwhelmingly preferred the 300 microseconds pulse duration regardless of waveform or source regulation, strongly preferred the symmetrical biphasic waveform, and had inconsistent preference for either regulated voltage or regulated current sources.

    Title L-dopa-induced Locomotor-like Activity in Ankle Flexor and Extensor Nerves of Chronic and Acute Spinal Cats.
    Date January 1985
    Journal Experimental Neurology
    Excerpt

    The ability of L-DOPA and nialamide to produce locomotor-like rhythmic discharges (fictive locomotion) in hind limb nerves of acute and chronically spinalized and paralyzed cats was examined. Ankle flexor and extensor nerves of chronic cats exhibited pharmacologically induced alternate bursts of activity that had significantly shorter cycle times and burst durations than those produced in ankle flexor and extensor nerves of acutely prepared cats. Furthermore, prior to pharmacologic activation, both ankle flexor and extensor nerves of chronic preparations frequently exhibited spontaneous alternate bursts of activity. Neuronal discharges from nerves of chronic preparations, both prior to and after pharmacologic activation, exhibited much greater variability in both cycle time and burst duration compared with those observed in acute preparations.

    Title Characterization of Synaptic Potentials in Hindlimb Extensor Motoneurons During L-dopa-induced Fictive Locomotion in Acute and Chronic Spinal Cats.
    Date August 1984
    Journal Brain Research
    Excerpt

    Intracellular recordings were carried out in extensor hindlimb motoneurons during L-DOPA-induced fictive locomotion from acute and chronically spinalized cats. It was demonstrated that motoneurons in chronic animals exhibited irregularly occurring, high frequency discharges within a given burst of a spike train, and sporadic membrane potential depolarizations and hyperpolarizations correlated with extensor and flexor nerve filament activity, respectively, during the locomotor cycle. In contrast, motoneurons recorded from acute cats demonstrated smooth membrane potential fluctuation and regularly occurring low frequency spike discharges. These results indicate that the pharmacologically activated central pattern generator (CPG) for locomotion in young adult chronic cats spinalized at two weeks of age produces disorganized locomotor-like patterns in the absence of sensory feedback. It is suggested that the above-mentioned characteristics of membrane potential fluctuations and spike discharges are not due to alterations in the motoneuron membrane properties, but instead are due to changes in the inputs to the motoneurons.

    Title Functional Test for the Hemiparetic Upper Extremity.
    Date May 1984
    Journal The American Journal of Occupational Therapy. : Official Publication of the American Occupational Therapy Association
    Excerpt

    A test, called the Functional Test, that evaluates the integrated function of the total upper extremity of an adult hemiparetic patient has been developed. It was used with 82 patients admitted to Rancho Los Amigos Hospital for stroke rehabilitation, together with a battery of six objective test measures. Sequential testing by two examiners demonstrated that the test had interrater reliability. The Functional Test score accounted for 87 percent of the variation in the scores achieved by the patients on the six separate objective measures. This tool integrates the information from these objective assessments and appears to be a valid measure of functional use of the hemiparetic upper extremity. The test can be administered in approximately 30 minutes, can be used in different treatment settings, and provides an accurate and immediate assessment of upper extremity capabilities.

    Title Neuromuscular Electrical Stimulation for the Head-injured Patient.
    Date January 1984
    Journal Physical Therapy
    Excerpt

    Recent research has shown that electrical stimulation is effective in treatment programs designed to maintain or gain range of motion, to facilitate voluntary motor control, and to strengthen muscles weakened by disuse. All of these treatment goals are relevant to the head-injured patient who frequently demonstrates profound disuse atrophy, joint contractures with excessive muscle tone, and decreased voluntary motor capabilities. As the cognitive status of the head-injured patient improves, electrical stimulation can be incorporated into traditional treatment programs to enhance their effectiveness. This article discusses using neuromuscular electrical stimulation with programs aimed at managing contractures, reducing spasticity, and facilitating voluntary motion. The limitations of electrical stimulation in the head-injured patient population are addressed.

    Title Electrical Stimulation of Wrist and Fingers for Hemiplegic Patients.
    Date February 1980
    Journal Physical Therapy
    Excerpt

    Passive cyclical electrical stimulation was applied during a four-week treatment program to the wrist and finger extensors of 16 hemiplegic patients with flexor spasticity. The study noted the effects of this treatment on the patients' sensation; spasticity; passive range of motion of the wrist, metacarpophalangeal, and proximal interphalangeal joints; and strength in the wrist extensor muscles. Patients were divided into chronic and subacute groups. Both groups received electrical stimulation for three half-hour periods a day, seven days a week, as a substitute for all other range-of-motion techniques. Flexion contractures were prevented in the subacute group of patients at the wrist, metacarpophalangeal, and proximal interphalangeal joints. A statistically and clinically significant increase in wrist extension range occurred in the chronic group that had wrist flexion contractures before the electrical stimulation. Increased extension was noted at the metacarpophalangeal and proximal interphalangeal joints of patients in the chronic group. Those patients with some voluntary wrist extension before the treatment began were able to increase their extension strength during stimulation. No changes in skin sensation were noted and only a general trend in decreasing spasticity was apparent.

    Title Positional Feedback and Electrical Stimulation: an Automated Treatment for the Hemiplegic Wrist.
    Date January 1980
    Journal Archives of Physical Medicine and Rehabilitation
    Excerpt

    Positional feedback (PF) and electrical stimulation were combined in a new treatment modality for facilitating wrist extension in stroke patients. Thirty adult hemiparetic patients lacking normal voluntary wrist extension were randomly placed in control and study groups. The control group received conventional therapy while the study group received positional feedback stimulation training (PFST) in addition to conventional treatment. At the end of the 4-week program, study patients showed a 280% increase in isometric extension torque when the wrist was positioned in 30 degrees of extension and 70% increase when positioned in 30 degrees of flexion. Control patients showed no significant changes in torque. Study patients made an average 200% gain in selective range of motion over their starting levels while controls made only a 50% increase. Treatment using automated PFST equipment allows controlled repetitive isotonic exercise and facilitation of wrist extension without continuous one-on-one therapist/patient supervision.


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