The effect of wrist position on the conduction velocity of the ulnar nerve.
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Adult↗
Biomedical subjects
M J Kothari
Publications and source records attributed to M J Kothari.
Urinary dysfunction in Duchenne muscular dystrophy.
In Duchenne muscular dystrophy (DMD), sphincter muscles tend to be clinically spared. However, urinary incontinence is occasionally reported, usually late in the course of the disease. We wished to determine the etiology of urinary dysfunction in patients with DMD. Seven boys with DMD and urinary dysfunction were examined by a neurologist and a urologist followed by urodynamic and electrophysiological assessment. Based on the results of these evaluations, patients were defined as having an upper motor neuron (UMN), lower motor neuron (LMN), or myopathic lesion. Five of the patients had UMN abnormalities consisting of either uninhibited contractions or bladder/sphincter dyssynergy. One patient had a LMN lesion with prolonged duration and high-amplitude motor units. No patient demonstrated myopathic motor units. Five boys had undergone spinal fusion for scoliosis. We conclude that urinary incontinence in DMD is most often due to UMN dysfunction and not due to a severe myopathy of the detrusor or external sphincter. The most likely causes of the UMN abnormalities are severe scoliosis or a complication of spinal fusion surgery.
Adolescent↗
Coexistent entrapment neuropathies in patients with amyotrophic lateral sclerosis.
OBJECTIVE: To determine the incidence of entrapment neuropathy in patients with amyotrophic lateral sclerosis (ALS). Although it is well known that patients with motor neuron disease may have coexisting focal neuropathies, their prevalence has not been previously determined. METHODS: Electrophysiologic studies (EMG/NCS) were reviewed from 126 patients with ALS seen at a university-affiliated hospital from 1991 to 1994. Every patient had an EMG/ NCS consistent with motor neuron disease (i.e., active and chronic denervation in at least 3 body regions). RESULTS: Forty-three percent (54 patients) had evidence of a neuropathy. Abnormalities included median neuropathy at the wrist in 15 (12%), ulnar neuropathy at the elbow in 18 (14%), nonlocalized ulnar neuropathy in 10 (8%), and peroneal neuropathy at the fibular head in 2 (2%). Furthermore, 9 patients (7%) had a superimposed polyneuropathy. Of these 54 patients, 7 (13%) had clinical symptoms of their neuropathy. CONCLUSIONS: Coexistent focal or generalized neuropathies in ALS are not uncommon. Careful attention to these abnormalities may decrease morbidity in these patients.
Adult↗
Comparison of the flexed and extended elbow positions in localizing ulnar neuropathy at the elbow.
Electrophysiologic localization of ulnar neuropathy at the elbow often depends on demonstration of segmental slowing. Based on normative data obtained from 50 control subjects, we compared the utility of flexed and extended elbow positions in demonstrating focal slowing at the elbow as compared to the forearm segment in patients with ulnar neuropathy. We studied 35 patients with ulnar neuropathy with definite electrophysiologic localization to the elbow segment defined by conduction block across the elbow segment or by focal slowing demonstrated either in the flexed or extended position. Applying cutoff values from the control group, all 35 patients demonstrated focal slowing at the elbow in the flexed position, whereas only 5 of 35 (14%) patients did so in the extended position. We conclude that the flexed elbow position is more sensitive than the extended position in localizing ulnar neuropathy at the elbow and should be the preferred method when performing ulnar motor conduction studies.
Adult↗
The limitations of the dorsal ulnar cutaneous sensory response in patients with ulnar neuropathy at the elbow.
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Adult↗
Comparison of digital sensory studies in patients with carpal tunnel syndrome.
Electrodiagnosis of carpal tunnel syndrome (CTS) often depends on the demonstration of focal slowing of median sensory fibers across the wrist. We compared the relative sensitivity of the four median innervated digits in demonstrating focal slowing in patients with CTS. Antidromic sensory studies of digits 1, 2, 3, and 4 were performed on 30 control subjects to develop normative data. Fifty-nine consecutive patients with CTS were then studied to determine the sensitivity of focal slowing of each median innervated digit. In the 26 CTS patients with a normal distal motor latency (DML) to abductor pollicis brevis, digit 1 was abnormal in 81%, digit 2 in 42%, digit 3 in 54%, and digit 4 in 38%. In the 33 CTS patients with a prolonged DML, digit 1 was abnormal in 94%, digit 2 in 88%, digit 3 in 91%, and digit 4 in 88%. We conclude that in milder cases of CTS with a normal DML, digit 1 is the most sensitive in identifying focal slowing of sensory conduction across the wrist. However, in patients with a prolonged DML, the sensitivity of sensory conduction is not significantly different among the four digits.
Action Potentials↗
Electrophysiological and urodynamic studies to monitor surgical outcome in children with tethered spinal cords.
Children with myelodysplasia often develop tethering of their spinal cord within 2-3 years after correction of their initial birth defect, leading to either neurological or urological dysfunction. Surveillance of these children includes electrophysiologic/urodynamic (EMG/UDS) studies to monitor improvement or deterioration of their neurological function. We reviewed 39 patients who underwent surgical untethering from 1979 to 1994 to determine whether postoperative EMG/UDS studies were useful in assessing outcome after surgery. All patients had a complete neurologic examination and an EMG/UDS prior to and 3 months after surgery. Twenty patients (51%) showed improvement in their EMG/UDS study after untethering, 15 (39%) demonstrated no significant change, and 4 (10%) showed deterioration. Improvement consisted of either return of previously absent motor units, return of sacral reflexes, or improved bladder dynamics. In a further 3 patients, subsequent deterioration on serial postoperative EMG/UDS testing was the first indication of recurrent tethering. We conclude that serial EMG/UDS evaluation in patients at risk for tethering of the spinal cord may serve as a useful adjunct to close clinical observation.
Child↗
Electromyography: do the diagnostic ends justify the means?
BACKGROUND: Physicians are sometimes reluctant to refer patients for electrodiagnostic studies (electromyography with nerve conduction studies [EMG/NCS]) believing the test is too painful and of little benefit. METHODS: We performed two separate surveys on 126 and 100 consecutive patients referred to our laboratory to determine if EMG/NCS was beneficial to the referring physician and to compare the level of anxiety experienced by patients before the study with the pain actually experienced during the study. RESULTS: The electrodiagnosis was discordant from the referring diagnosis in 39% of the patients with an abnormal EMG/NCS. Pretest anxiety levels were low in 59% of the patients, medium in 27%, and high in 14%. After the tests, 82% of the patients said that the test was not as bad as expected, and was generally only mildly painful. Ninety-three responded that they would have the test performed again. CONCLUSIONS: EMG/NCS often suggest alternative diagnoses, and the actual pain experienced during an EMG/NCS study is significantly less than expected.
Adult↗
Neurophysiologic assessment of urinary dysfunction in children with thoracic syringomyelia.
Isolated syringomyelia of the thoracic portion of the spinal cord is relatively uncommon. In children, signs and symptoms may involve only the urinary system. Five children who presented for evaluation of urinary tract dysfunction were found to have syringomyelia of the thoracic cord not associated with any other central nervous system abnormality on radiographic imaging. Each child underwent a complete neurologic examination and a complete electrophysiologic/urodynamic evaluation. One patient underwent surgical drainage of the syrinx due to progression of neurologic deficit, with slight improvement; three patients were treated pharmacologically to control the urinary dysfunction.
Child↗
The median-ulnar latency difference studies are comparable in mild carpal tunnel syndrome.
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Adult↗
Median nerve function in patients undergoing carpal tunnel release: pre- and post-op nerve conductions.
Patients undergoing surgery for carpal tunnel decompression may improve clinically, however it is not well known as to how median nerve neurophysiology is altered following surgery. Fifty patients who underwent open carpal tunnel release were prospectively studied. Each patient underwent nerve conduction studies pre-op and at 6 months post-op. Patients were also asked to answer several questions regarding their clinical symptoms to see how they improved. 48/50 patients had clinical improvement based on their response (resolution of nocturnal paresthesias, decreased sensory complaints and pain). Average pre- and post-op parameters were as follows: distal motor latency (DML) (msec) 5.24/4.42; distal motor amplitude (mV) 8.28/8.64; sensory conduction velocity (m/sec) 38.9/41.0; sensory amplitude (uV) 10.94/15.61. We conclude that the DML and sensory amplitude showed significant improvement following surgery; the sensory conduction velocity remains slow.
Carpal Tunnel Syndrome↗
Levetiracetam induced polyneuropathy: a case report.
We report the first case of polyneuropathy induced by levetiracetam, an anti-epileptic medication. Follow up electrodiagnostic studies showed significant improvement after discontinuation of the medication.
Adult↗