Antidromic sensory nerve conduction studies of medial and lateral plantar nerves in normals.

A reliable sensory nerve conduction study for the most distal lower extremities is needed in routine clinical electromyography. This paper reports a study of 150 medial and lateral plantar nerves in the foot in normals. An antidromic technique was used with stimulation at the ankle and recording from the small and large toes. Recordable responses were obtained in 149 instances. Conduction velocity in the medial branch distal to the tarsal tunnel was 40.5 +/- 4.0 m/sec and significantly slower than conduction in the lateral branch by 4.3 m/sec. The amplitude of the evoked response from the big toe was 3.46 +/- 2.2 microV and significantly larger than that in the small toe by 1.34 microV. Evoked response amplitude in the medial branch was greater in younger subjects.

Baclofen-induced dyskinesia.

Baclofen (Lioresal) is a derivative of the inhibitory neurotransmitter gamma-aminobutyric acid (GABA). It is used to treat spasticity particularly for the relief of flexor spasms, pain, clonus, and muscular rigidity. There have been many rare neurologic side effects reported with its use. These side effects, in particular, hallucinations and seizures, have been observed predominantly following precipitous withdrawal of the drug. We present a case demonstrating a muscular dyskinetic side effect when baclofen treatment was first initiated. The mechanism by which baclofen affects spasticity and how the resulting side effect of dyskinesia developed in our patient is not known. They are, however, most probably related to dopamine receptor hypersensitivity and the resulting imbalance of the dopaminergic/cholinergic systems. Clinicians should be aware of this additional adverse effect of muscular dyskinesia, with the use of baclofen, and its reversibility when baclofen is discontinued.

Evoked electromyography and idiopathic facial paralysis.

The purpose of this study was to standardize and evaluate the results of evoked electromyography (EEMG) in normal patients and in patients with acute idiopathic facial paralysis. A comparison of the amplitude of response to EEMG from one side of the face to the other in 288 normal patients yielded a great variability in results. The amplitude difference was not greater than 50%, and therefore a difference of less than 50% was considered normal. Test-retest variability of the percentage difference in amplitude in 10 subjects showed a 10% variation in seven patients and up to a 20% variation in the remaining three patients. Fifty patients with acute idiopathic facial paralysis were seen within 14 days of onset. A favorable prognosis was based on an EEMG amplitude of more than 25% of the normal side. With this criterion EEMG was accurate in predicting complete recovery in 36 (92%) of 39 patients. When EEMG was 25% of normal or less, incomplete recovery occurred in 9 (82%) of 11 patients. The response was 0% to 10% in six patients; four had a poor recovery and the remaining two had a fair recovery. The technique, interpretation of results, avoidance of pitfalls, and shortcomings of this test are discussed.

Acute Bell's palsy: prognostic value of evoked electromyography, maximal stimulation, and other electrical tests.

Thirty-seven patients with acute Bell's palsy who had complete unilateral facial paralysis were selected for this study. Evoked electromyography, conduction latency, electromyography, and nerve excitability testing was done by one author while the maximal stimulation test was done by another on each patient. The patients were examined within ten days of onset of facial paralysis and evaluated six months after onset to determine the degree of recovery of facial motor function. The results of the tests were correlated with the degree of recovery of facial motor function in each patient. Evoked electromyography and maximal stimulation tests were the most accurate electrical tests for predicting the course of acute facial paralysis when they were performed serially within the first ten days after onset. When the results of the maximal stimulation test were equal on the involved and uninvolved sides of the face, there was a 92 percent chance of complete recovery of facial function on the involved side. In those patients in whom the response to the maximal stimulation test was markedly reduced or absent, there was an 86 percent chance of incomplete recovery of facial function. When the response to evoked electromyography on the involved side was 30 percent or greater of that on the normal side, 84 percent of the patients had complete recovery of facial function; however, when the response was 25 percent or less of normal, there was an 88 percent chance of incomplete recovery. The results of evoked EMG and the maximal stimulation test agreed in 89 percent of cases in predicting the ultimate outcome of facial paralysis.

Herpes zoster oticus: surgery based upon prognostic indicators and results.

We studied 28 patients with herpes zoster oticus prospectively over the six-year period between August 1974 and June 1980. We found that the results of measuring tear production, submandibular salivary flow, the response to maximal stimulation, and evoked electromyography gave us sufficient information to group these patients according to prognosis--either unfavorable or favorable--for spontaneous return of facial function. When the test results were 26% or more of normal, 100% of the patients had complete recovery without treatment; when the test results were 25% or less of normal, 69% had incomplete recovery: 19% had fair and 50% had poor recovery. Of the 31% with complete recovery, 4 were operated upon. The natural history of herpes zoster oticus in patients with a poor prognosis was improved if a transmastoid extralabyrinthine subtemporal decompression of the labyrinthine segment of the facial nerve was performed within 10 days of onset of the paralysis. The decision to perform this surgery was based upon the results of the prognostic tests mentioned above.

Bell's palsy: surgery based upon prognostic indicators and results.

We studied 164 patients with Bell's palsy prospectively over the six-year period between August 1974 and June 1980. We found that the results of measuring tear production, submandibular salivary flow, the response to maximal stimulation, and evoked electromyography gave us sufficient information to group these patients according to prognosis--either unfavorable or favorable--for spontaneous return of facial function. When the test results were 26% or more of normal, 90% of the patients had complete recovery of function; these patients were given a favorable prognosis on the basis of the results of tests described above. The natural history of Bell's palsy in patients with an unfavorable prognosis could be improved if a transmastoid facial nerve decompression to the labyrinthine segment were performed. The results were better with this approach than with supportive or steroid therapy or transmastoid vertical-horizontal surgical decompression of the facial nerve.

Facial paralysis in children: differential diagnosis.

The differential diagnosis in 170 patients between birth and 18 years of age is reviewed. There are a number of obvious physical findings and historical features that allow one to make a diagnosis rather quickly. Pain, vesicles, a red pinna, vertigo, and sensorineural hearing loss suggest herpes zoster oticus. Slow progression beyond three weeks, recurrent facial paralysis involving the same side, facial twitching, weakness, or no return of function after six months indicate a neoplasm. Bilateral simultaneous facial paralysis indicates a cause other than Bell's palsy, such as Guillain-Barré syndrome, pseudobulbar palsy, sarcoidosis, and leukemia. Recurrent facial paralysis associated with a fissured tongue, facial edema, and a positive family history should suggest Melkersson-Rosenthal syndrome.

Complications of total ischiectomy for the treatment of ischial pressure sores.

Five patients are reported, 4 of whom had total ischiectomies and the other an extensive partial ischiectomy. In each, recurrent ulcers, extending into the perineum, developed subsequently. One patient had a urethrocutaneous fistula as a result of his perineal ulcer, and he had to undergo an ileal loop diversion. Following a unilateral ischiectomy, the pressure is shifted to the opposite ischium, and this favors the development of another ischial pressure sore on the opposite side. After bilateral ischiectomy there is much more pressure on the perineum, and these patients may go on to develop a perineal pressure sore--particularly if there is a dislocated hip. Recurrent pressure sores which extend into the perineum are difficult to treat, and usually they appear to be related to a previous extensive removal of the ischia.