Prolonged peroneal nerve dysfunction after high tibial osteotomy: pre- and postoperative electrophysiological study.

To evaluate electrophysiological incidence and the type of peroneal nerve lesions seen after high tibial osteotomy we conducted an electrophysiological study (electromyography and nerve conduction velocity studies) in 11 patients who were suffering from medial gonarthrosis and treated by Maquet barrel-vault type high tibial valgization osteotomy. All the patients were tested both pre- and postoperatively. Every patient was examined postoperatively for a minimum of a 6 months after surgery to eliminate spontaneously reversible lesions. Results obtained from nonoperated legs served as controls. Three patients (27%) with peroneal nerve lesions were detected electrophysiologically; one had only motor involvement, one only sensory involvement, and one both motor and sensory involvement. Clinically only one of these patients was symptomatic, and the other two were detected by electrophysiological means. Peroneal nerve lesions which may be overlooked by mild weakness and hypesthesia in the early postoperative period can be detected by electrophysiological means at a higher rate than expected. These lesions persist a relatively long time and even can be permanent despite the absence of clinical symptoms.

Use of levodopa to relieve pain from painful symmetrical diabetic polyneuropathy.

Levodopa has been used to treat some painful conditions and found to be effective in neuropathic pain due to herpes zoster in a double-blind study. From our anecdotal observations about the efficacy of levodopa on diabetic neuropathic pain, we designed a double-blind placebo-controlled study to test levodopa in painful diabetic neuropathy. Twenty-five out-patients with painful symmetrical diabetic polyneuropathy were admitted to the study. Fourteen patients were given 100 mg levodopa plus 25 mg benserazide to be taken three times per day for 28 days. Eleven patients were given identical placebo capsules. A blinded neurologist evaluated the patients clinically and performed Visual Analogue Scale (VAS) measurement every week from day 0 to day 28. The results seemed promising and levodopa may be a choice for the control of pain in neuropathy for which we do not have many alternative treatments.

Motor-evoked potentials from various levels of paravertebral muscles in normal subjects and in patients with focal lesions of the spinal cord.

STUDY DESIGN: This prospective study includes normal control subjects and patients with focal lesions of the spinal cord investigated by transcranial magnetic stimulation. OBJECTIVES: To establish a stable method to elicit motor evoked potentials from cervical to lumbar segmental levels and to apply the method that would allow the localization in patients with restricted cord lesion. Thirty-four healthy subjects (10 women, 24 men) and 17 patients with focal spinal lesions were admitted to this study. SUMMARY OF BACKGROUND DATA: The focal cord lesions and injuries were previously evaluated by the records of lower limb muscles after cortical stimulation, but this method did not demonstrate the vertebral levels at which the lesions were located. METHODS: The paravertebral myotomal-evoked potentials were recorded in different segmental levels (T1, T6, T12, and L3) from paravertebral muscles, using surface and needle electrodes by transcranial magnetic stimulation in normal control subjects and patients. RESULTS: In normal control subjects, paravertebral myotomal-evoked potentials were obtained from T1, T6, T12, and L3 paravertebral muscles with both recording techniques (surface and needle electrode). From T1 to L3 latencies of paravertebral myotomal-evoked potentials increased gradually (from 10 msec to 17 msec) in normal control subjects. The levels of spinal cord lesions were obtained reliably in 14 of 17 patients with thoracic-lumbar spinal cord lesions, by using both electrophysiologic methods. In 11 of 14 patients, the lesions produced total conduction block, at and below the lesion level. In the remaining 3 patients slowing of intersegmental conduction was observed along the focal cord lesion. CONCLUSIONS: The paravertebral myotomal-evoked potentials obtained by surface electrode from paravertebral muscles and by midline needle electrode in the intrinsic rotatory muscles of the spine were useful in localizing lesions in the spinal segments in most of the patients with thoracic-lumbar cord lesions.

A special kind of anterior horn cell involvement in juvenile myoclonic epilepsy demonstrated by macro electromyography.

Juvenile myoclonic epilepsy (JME) is not an uncommon seizure disorder, occurring in 5-10% of epileptic patients. A subclinical anterior horn cell involvement has been suggested in some JME patients by concentric needle electromyography (EMG) and turn/amplitude analysis. In this study, 22 JME patients and 17 normal control subjects have been studied with macro EMG, which is a sensitive method to assess the size of motor units. Most JME patients (19 of 22) had a pathologically increased number of individual large macro motor unit action potentials (MUAPs) compared to control subjects. For both biceps brachii and tibialis anterior muscles, means of median macro MUAP amplitudes were significantly greater than those of normal controls, whereas the fiber density values were only slightly increased. This suggested another kind of anterior horn cell involvement in JME than seen in motor neuron diseases.

A stable late soleus EMG response elicited by cortical stimulation during voluntary ankle dorsiflexion.

Transcranial electrical or magnetic stimulation was performed in 47 experiments on 42 normal adult subjects. Surface compound muscle action potentials were recorded from the antagonistic tibialis anterior (TA) and soleus (SOL) muscles. A stable late response recorded from SOL during voluntary ankle dorsiflexion is described and called soleus MEP-80. Its origin has been studied with different experimental procedures. (1) It is only obtained during active voluntary dorsiflexion of the ankle within 70-100 msec (mean 86.9 +/- 6.4 msec) whereas passive dorsiflexion does not promote such a response. The size of SOL MEP-80 was always bigger than the primary SOL response. (2) A similar constant response has not been obtained during voluntary plantar flexion from SOL and TA muscles. (3) SOL MEP-80 is not changed significantly by the Jendrassik manoeuvre. (4) It is not obtained or is suppressed when the subject is sitting with the feet free in space. On the other hand, it is obtained when the subject is standing, especially when standing is made difficult. (5) SOL MEP-80 has not been obtained by brain-stem, spinal cord or root stimulation. (6) A later response of longer than 100 msec latency was sometimes obtained at rest but such an S100 soleus response was abolished or transformed to the SOL MEP-80 immediately during ankle dorsiflexion. (7) It is concluded that SOL MEP-80 is a polysynaptic extensor response related to postural mechanisms and originating through convergence of descending motor commands and peripheral sensory feedback.

Prognostic value of transcranial magnetic stimulation in acute stroke.

BACKGROUND AND PURPOSE: The aim of this study is to evaluate the role of motor-evoked potentials (MEPs) in predicting functional recovery of hemiparesis and hemiplegia in acute stroke patients. METHODS: Twenty-seven acute stroke patients were evaluated clinically and electrophysiologically within the first week and 3 to 6 months after the event. Clinical assessment included a quantitative evaluation of motor ability and activities of daily living. MEPs were recorded from the abductor pollicis brevis and tibialis anterior muscles bilaterally. Correlations between clinical parameters and MEPs were assessed. RESULTS: In the acute period, no MEP could be detected in 17 of 27 patients. In these 17 patients, the clinical scores were worse than in the patients whose MEPs could be elicited. However, in the follow-up period (3 to 6 months), no significant differences in motor function were observed between the two groups. CONCLUSIONS: In the acute phase of stroke, neurophysiological parameters were correlated with the clinical findings, but MEPs had no value in predicting the outcome of hemiparesis and hemiplegia.

Diagnostic value of electrical stimulation of lumbosacral roots in radiculopathies.

Needle electrical stimulation of the lumbosacral roots at the laminar level of the Th12-L1 or L1-2 intervertebral spaces were performed in 24 normal subjects and 58 patients with various kinds of lumbar radiculopathy (unilateral L4, L5 and S1 herniated nucleus pulposus and lumber stenosis). The root stimulation method was compared with conventional needle EMG. Lumber electrical stimulation showed root abnormalities objectively in 80% of patients while the diagnostic value of needle EMG was 65%. Therefore, electrical root stimulation is superior to routine EMG for localizing lumbar root involvement. However, the only needle EMG demonstrated the root pathology in 7 cases (12%) and single electrophysiological abnormality was found by the root stimulation in 16 cases (27%). Thus, both electrophysiological methods should be complementary to each other in evaluation of the lumbar radioculopathy.

Comparison of magnetic coil stimulation and needle electrical stimulation in the diagnosis of lumbosacral radiculopathy.

Electrical stimulation (ES) of lumbosacral nerve roots using a needle electrode inserted to the laminar level at the midline of Th12-L1 or L1-2 intervertebral interspace, was compared with magnetic stimulation using a 9-cm diameter coil (MCS) at the L3-4 or L4-5 spine levels, Compound muscle action potentials (CMAP) were superficially recorded from homologous muscles in both sides in 15 normal control subjects and in 20 patients with lumbosacral radiculopathy. Soleus muscles were used for S1, tibialis anterior (TA) for L5, and rectus femoris (RF) muscles for L4 roots. According to the clinical or radiological diagnosis (CAT, MRI and/or myelography) conventional needle EMG was capable to localise the root lesion in 16 of 20 patients (80%) and ES localised the root involvement in 18 of 20 patients (90%); the diagnostic value of MCS was lower, about 65% (13 of 20 patients). Although ES is uncomfortable and invasive, it is superior to needle EMG in localising unilateral or multiple lumbosacral root involvement. At present, MCS is not suitable for the diagnosis of lumbar radiculopathy.

Ice test as a simple diagnostic aid for myasthenia gravis.

It is known that myasthenia gravis is improved by cold. In two previously reported studies performed on a limited number of myasthenic patients and controls, local cold application to the eyelid was suggested for use as a diagnostic test for ocular myasthenia gravis. In this study, ice test to the eyelid was evaluated as a diagnostic test on 12 myasthenic patients and 15 controls with blepharoptosis and the results were compared with those of edrophonium test.

Subclinical anterior horn cell involvement in juvenile myoclonic epilepsy.

Although clinical signs of muscle wasting and weakness were not present, electromyographic (EMG) evidence of subclinical anterior horn cell involvement of spinal cord was noted in 5 patients with juvenile myoclonic epilepsy (JME). Quantitative interference pattern analysis of EMG recorded from the anterior tibial muscle showed that the ratio (amplitude:turn/turn:second, A:T/T:S) was significantly increased in 10 patients with JME and 12 patients with lower motor neuron disorders (LMND) as compared with those of 22 normal subjects and 15 patients with frequent generalized tonic-clonic seizures (GTC). Subclinical anterior horn cell involvement detected by EMG techniques can be related to a genetically determined component of JME.

Early-onset cerebellar ataxia with retained tendon reflexes.

The authors report a clinical review of 16 childhood cases with early-onset cerebellar ataxia with retained tendon reflexes. The preservation of tendon reflexes distinguishes this disorder from Friedreich's ataxia. The mean age of onset of symptoms was 7.1 years. The main presenting symptom was abnormal gait (100%). Ataxia of gait and limbs and normal or increased tendon reflexes were found in all cases. This disorder is associated with dysarthria, pyramidal signs in the limbs, and in some instances, sensory loss. Other important differences from Friedreich's ataxia are absence of optic atrophy, diabetes mellitus, cardiomyopathy and severe skeletal deformity. Sensory nerve conduction was found to be normal, excluding one case. This finding constitutes another aspect of the syndrome different from Freidreich's ataxia. CT scans were normal in 2 of the 4 cases. The remaining two cases showed cerebellar atrophy. Inheritance is probably autosomal recessive in the majority of cases.

Friedreich's ataxia: a clinical review of 20 childhood cases.

The authors report the clinical review of 20 childhood cases with Friedreich's ataxia. The mean age at onset of symptoms was 6.1 years. The main presenting symptom was abnormal gait (100%). Ataxia of gait and limbs and depressed or absent tendon reflexes were found in all cases. Clinical findings are in accordance with the findings of Harding and Werdelin. Neurophysiological studies (especially sensory) are important in the confirmation of the diagnosis. Of the 10 cases in which sensory nerve conduction velocity measurements were performed, 7 had absent sensory action potentials, 2 had decreased potentials and one was normal. In our study, it is shown that in patients having ataxic gait, ataxia of limbs and tendon reflexes depression or loss, Friedreich's ataxia may be diagnosed with the help of electrophysiological studies.

Recurrent multiple cranial nerve palsies (Tolosa-Hunt plus?).

Twelve patients with recurrent cranial nerve palsies in whom no focal cause was found were seen during a period of 4 years. The literature is reviewed, and the relationship and similarity to Tolosa-Hunt syndrome is discussed. Early recognition is important since the response to steroids, although not specific, is rapid in most patients, and the prognosis for complete recovery is relatively good.