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Biomedical subjects

M H Rivner

Publications and source records attributed to M H Rivner.

16 recordsLinked to original sources

An open-label study of botulinum toxin A for treatment of tardive dystonia.

Tardive dystonia is a form of tardive dyskinesia for which there is little satisfactory treatment. We reviewed our experience at four movement disorder centers in the treatment of tardive dystonia with botulinum toxin A (BTX-A). Thirty-four patients with relatively localized tardive dystonia unresponsive to oral medications were treated with injections of BTX-A into dystonia muscles. Cervical dystonia was the most frequent manifestation of tardive dystonia in this group of patients. There was marked or moderate improvement in 29 of 34 patients. Eighteen of 24 patients with cervical dystonia showed either marked or moderate improvement. In this retrospective review, BTX-A provided useful symptomatic treatment for localized dystonia in patients with tardive dystonia unresponsive to other treatment. A controlled, prospective trial of BTX-A in tardive dystonia is warranted.

Botulinum Toxins, Type A

Statistical errors and their effect on electrodiagnostic medicine.

Failure to demonstrate abnormalities on diagnostic tests in patients felt certain to have a disease is all too common, especially when symptoms are mild to moderate. One strategy used in such cases is to perform multiple tests hoping that one will confirm the clinical suspicion. An example of this strategy is found in carpal tunnel syndrome where multiple tests are often used to confirm the diagnosis. Unfortunately, this approach is often erroneous. Since no diagnostic test can perfectly discriminate between normal and abnormal, critical values are set at levels where most subjects are correctly classified. Using this methodology, approximately 2.5% of patients who are normal will be mistakenly called abnormal. This type I error, is additive when additional independent tests are performed. Since no two tests for a single condition are completely independent, the total error is less than the sum of the individual errors for each test. Even after accounting for interdependency, the total error of combined tests may be unacceptably high. If a single, highly discriminating, test is not available and multiple tests are used, abnormalities in more than a single test are needed to distinguish between normals and abnormals.

Carpal Tunnel Syndrome

Toward more rational nerve conduction interpretations: the effect of height.

One hundred four normal subjects ranging in age from 17 to 77 years and in height from 115 to 203 cm underwent nerve conduction studies of sural, peroneal, tibial, and median nerves. Foot temperature was measured in each patient. A strong inverse correlation was found between height and sural (r = -0.7104), peroneal (r = -0.6842), and tibial (r = -0.5044) conduction velocities. These correlations were significant at the P less than 0.001 level. Median conduction velocity was not correlated with height. Height was correlated with the distal latencies of all nerves studied (sural r = 0.6518, peroneal r = 0.4583, tibial r = 0.7217, median r = 0.5440). These correlations were significant at the P less than 0.001 level. Age was inversely correlated with both tibial (r = -0.4071) and median (r = -0.3464) nerve conduction velocities but not with sural and peroneal conductions. There were no correlations between distal latencies and age. If the variation in conduction velocity accounted for by the linear relationship with height was removed, then age would be inversely correlated to all conduction velocity measurements with the exception of the sural. Temperature is inversely correlated with the sural (r = -0.2233), peroneal (r = -0.2102), and tibial (r = -0.2710) distal latencies. In all instances, the effects of age and temperature were minor determinants when compared with the effects of height. Diagnostic conclusions made from nerve conduction data without correcting for height may be invalid in patients taller and shorter than normal.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent

Kearns-Sayre syndrome and complex II deficiency.

A 25-year-old woman with Kearns-Sayre syndrome (KSS) had complete external ophthalmoplegia, short stature, ataxia, cardiac conduction defects, and pigmentary retinopathy. Muscle biopsy revealed ragged-red fibers. Electron microscopy showed increased numbers of mitochondria with disordered structure and paracrystalline inclusions. Enzymatic analysis revealed a deficiency of complex II of the mitochondrial respiratory chain, and, more specifically, a deficiency of succinic dehydrogenase, although both subunits of this enzyme proved to be present by immunologic analysis. Therapy with vitamin cofactors did not result in short-term improvement. This appears to be the first report of complex II deficiency in a patient with KSS.

Adult

Growth of skeletal muscle from patients with amyotrophic lateral sclerosis transplanted into nude mice.

We studied the fate of skeletal muscle obtained from patients with amyotrophic lateral sclerosis (ALS) after transplantation into immunodeficient nude mice. The transplanted muscle consistently survived in the nude mice without immunological rejection. The myofibers in these muscles underwent degeneration, followed by regeneration, maturation, and eventual functional innervation by the mouse motor neurons. The ability to grow diseased human muscle successfully over a prolonged period in nude mice offers an in vivo model to study the etiology of ALS and possibly of other neuromuscular disorders.

Aged

False positive electrodiagnostic tests in carpal tunnel syndrome.

Of 50 normal subjects, 23 (46%) had at least one false positive electrodiagnostic test for carpal tunnel syndrome (CTS). There were 30% of the subjects who exhibited an abnormal median to ulnar sensory amplitude ratio of less than 1.1. In 7 subjects 8 extremities (14%) revealed prolonged residual latencies, and 4 extremities in 4 subjects (8%) had a difference of 0.4 msec between the median and ulnar palmar sensory latencies. The results of this study indicate that certain reported criteria for CTS are abnormal in a high percentage of normal subjects, thereby making them of limited value in the diagnosis of CTS. Of all the criteria studied, it appears that the comparison of the median to ulnar sensory latency across the carpal tunnel is of greatest potential value. However, even here a more conservative difference of 0.5 msec between median and ulnar nerves must be used to avoid false positive tests for CTS.

Adult

Ice pack test for myasthenia gravis.

A common symptom of myasthenia gravis is eyelid ptosis. Often, the edrophonium test is negative, particularly in ocular myasthenia gravis. Myasthenic weakness is often improved by cold. We applied ice packs to the eye in 10 myasthenic patients and 7 disease controls. Eight of 10 patients with myasthenia gravis improved, whereas none of the controls improved. The ice pack test is useful in the diagnosis of myasthenia gravis.

Adolescent

Opsoclonus in Hemophilus influenzae meningitis.

We studied a 3-month-old boy who had opsoclonus in association with acute bacterial meningitis. The CSF IgG and IgM were elevated acutely, gradually returning to normal with clinical improvement. Correspondingly, CSF cytomorphology showed excessive plasmocytosis and a higher proportion of reactive lymphocytes than expected in an acute bacterial meningitis. These abnormalities in CSF cytology are effects of an abnormal immune response in the CNS, and provide evidence to support an immunopathic basis to opsoclonus.

Eye Movements