Central conduction and autonomic nervous function in HMSN I.

CNS conduction and autonomic nervous function were investigated in 15 patients with HMSN I. Central motor conduction time (CMCT) was estimated with magnetic brain stimulation and electrical nerve root stimulation. Somatosensory evoked potential (SEP) and visual evoked potential (VEP) were used for assessment of central sensory and visual conduction. Autonomic effector organ functions were assessed with the R-R variation test for parasympathetic function, and the sympathetic skin response test (SSR) for skin sympathetic sudomotor activity. Five of the patients had prolonged CMCT. Central sensory conduction was normal in 3, and slightly prolonged in 1 of the patients, but could not be estimated in 11 due to lack of response from the cervical recording. VEP was abnormal in 2 patients. R-R variations during normal breathing were low in 8 of 15 patients, and low also during deep breathing in 1 of 15. The SSR test was pathological in 5 of 15 patients. Thus, impaired central conduction and/or autonomic dysfunction was not an uncommon finding in patients with HMSN I.     

Somatosensory evoked responses in the diagnosis of thoracic outlet syndrome.

A study was made of 11 patients with cervical rib, and one patient with Klippel-Fiel syndrome and enlarged transverse processes to determine whether evoked potentials recorded from both Erb's points and the cervical spine in response to median and ulnar nerve stimulation provided information additional to that obtained by EMG and peripheral conduction studies. It was found that in seven patients who had pain and paraesthesias but no objective neurological signs both the peripheral and central conduction studies were within normal limits. By contrast, of five patients who had objective signs, conventional EMG and conduction studies were abnormal in three patients, but abnormalities of the evoked potentials obtained from ulnar nerve stimulation were obtained in all five patients. It is suggested that this application of evoked potential estimation is a useful addition to the more conventional peripheral investigations.     

Evoked potential studies in Friedreich's ataxia and progressive early onset cerebellar ataxia

We recorded somatosensory evoked potentials (SEP) in 15 patients affected by Friedreich's ataxia (FA) and in 9 patients with progressive early onset cerebellar ataxia (PEOCA). Brainstem auditory evoked potentials (BAEP) were also recorded in 14 FA patients and in five PEOCA patients. SEP results showed clear differences between groups of FA, evidence of peripheral involvement was seen in all patients, with absence of the N9 potential or a major reduction of its amplitude. In patients in whom central responses could be recorded, conduction velocity was normal or near normal up to the brainstem but was reduced from brainstem to cerebral cortex. Four patients with PEOCA had SEP abnormalities similar to those seen in FA. In the five other patients, the amplitude and latency of N9 were normal but conduction velocity was reduced from brainstem to cerebral cortex. In FA, BAEP were abnormal in all patients with a disease duration of four years or more but were normal in four of the five PEOCA patients. Systematic evoked potential recording is useful in the investigation of hereditary ataxias.     

ROSS SYNDROME: CLINICAL AND LABORATORY EVALUATION OF TWO CASES

We describe two males, aged 41 and 55, come to our observation complaining of heat intolerance, abnormal increase in body temperature with minimal exercising, reduced sweating and, generalized fatigability; one of them had distal paresthesias. Neurologic evaluation showed bilateral Adie's tonic pupil and an absence of deep-tendon jerks. A diagnosis of Ross' Syndrome was advanced. Autonomic tests, nerve conduction study, H-reflex, computerized termoregulatory and pain thresholds, laser CO₂ cortical evoked potentials, and skin biopsy were performed. One of them performed a histamine test and hand photopletismography resulted positive for sympathetic impairment, and pilocarpine pupil test that showed a parasympathetic denervation hypersensitivity.
The following tests gave the same results in both patients: parasympathetic and most sympathetic tests were normal. Sympathetic skin response was absent and Minor test showed an almost complete absence of sweating. Sweating was possible only in two or three small areas. Positive pilocarpine test suggested a postganglionic involvement of sympathetic nervous system. Sensitive and motor nerve conduction velocities were normal, while H-reflex was not detectable. Termoregulatory and pain thresholds were abnormal. Laser CO₂ cortical evoked potentials showed the absence of C fibre potentials, whereas A-δ fibres response was abnormal in one of them. Hairy skin biopsy showed a definite reduction of sweat glands and of small vessel innervation; glabrous skin biopsy performed in one of them showed a reduced number of Meissner corpuscles. These findings suggest that in Ross' Syndrome the degenerative process can involve, besides the autonomic fibres, myelinated somatosensory fibres also.     

Comparison of sympathetic sudomotor and skin responses in alcoholic neuropathy

We evaluated sympathetic sudomotor and parasympathetic vagal function in 30 chronic alcoholic patients and 28 control subjects by means of silicone imprints, sympathetic skin responses (SSR), and cardiorespiratory reflex tests. Mean values from alcoholic patients were significantly lower than those from control subjects for all tests. The number of secreting sweat glands (SGN) was below normal in the foot of 18 patients, and in the hand of 7 patients; 16 patients had absent SSR on the sole, and 4 on the palm. Only two patients had both test results abnormal on the hand and 10 on the foot. The SGN did not correlate with the amplitude of the SSR in the subjects studied. There was no clear correlation of abnormalities found in cardiorespiratory tests and sympathetic tests. Abnormalities in sensory nerve conduction were associated with absent SSR, but not with decreased SGN. The silicone mold technique is a more specific test to detect abnormalities in sympathetic efferent fibers, as SSR may be influenced by sensory afferent fiber involvement. © 1993 John Wiley & Sons, Inc.     

Parasympathetic denervation of the iris in Chagas' disease

The parasympathetic innervation of the iris along with cardiovascular reflexes involving parasympathetic and sympathetic function were studied in 45 patients with Chagas' disease and in 36 controls. The autonomic features in Chagas' disease included 15 with cardiomyopathy, three with megaoesophagus and five with megacolon. None of the patients had orthostatic hypotension. Parasympathetic cardiac reflexes (deep breathing 30:15 ratio, Valsalva) were abnormal. There were exaggerated pupillary responses to dilute pilocarpine. These studies suggest iris parasympathetic denervation and favour more widespread cholinergic involvement in patients with Chagas' disease, than previously recognized.     

The sympathetic skin response in peripheral autonomic failure — evaluation in pure autonomic failure, pure cholinergic dysautonomia and dopamine-beta-hydroxylase deficiency

The sympathetic skin response (SSR) detects changes in the electrical potential in the skin in response to physiological and electrical stimuli and, therefore, may indicate the integrity of sympathetic cholinergic neural pathways to sweat glands. This has been evaluated in 21 patients with three different forms of peripheral autonomic failure. Of these, 15 had pure autonomic failure (PAF) without additional neurological features; investigations indicated both sympathetic and parasympathetic failure. Four patients had pure cholinergic dysautonomia (PCD), with clinical and laboratory features indicating only cholinergic failure. Two siblings had dopamine-betahydroxylase (DBH) deficiency with only sympathetic adrenergic failure. None was on drugs affecting cholinergic function. Ten normal individuals were aged-matched with PAF patients and studied as controls. The SSR was recorded from the palmar hand and plantar foot surfaces, using previously described techniques, in response to physiological (auditory, cough and inspiratory gasp) and electrical stimuli. Nerve conduction studies excluded an associated motor or sensory neuropathy.The SSR was present in all normal individuals, and in both patients with DBH deficiency who had preserved cholinergic and subdomotor function. It was absent in all 15 PAF and all four PCD patients with impaired cholimergic function. Therefore, we conclude that the SSR reflected sympathetic cholinergic function in these three different groups with peripheral autonomic failure. Clin Auton Res 8:133–138     

Evoked potentials show early and delayed abnormalities in children with congenital hypothyroidism

To evaluate the effect of congenital hypothyroidism (CH) on nervous system development, we performed evoked potential studies on 7 CH infants at 3-8 weeks of age before treatment and at four months or more after treatment began. All infants were screened using filter paper determination of T4 and TSH, confirmed by serum specimen determinations. These infants had serum TSH concentrations greater than 100 microU/ml (normal less than 7), and the serum T4 range was 4.1-8.5 micrograms/dl. All had thyroid tissue on 99Tc scan; five had ectopic thyroid tissue, and two had a thyroid gland in the normal location. Four older CH children were tested after 3-6 years of treatment. Brainstem auditory evoked potentials (BAEP) were abnormal in three of the 7 infants and showed bilateral conduction delays in caudal brainstem regions. The BAEP became normal after 6 months of thyroxine treatment. Visual evoked potentials (VEP) were abnormally delayed and had an immature pattern in the four patients tested at four weeks of age. At age 8 weeks, even in untreated patients, the VEP was normal and remained so. Somatosensory evoked potentials (SSEP) were normal at the time of diagnosis. However, seven patients tested after at least five months of therapy had prolonged central conduction times. We conclude that infants with relatively mild CH (serum T4 values greater than 4 micrograms/dl at 3-8 weeks of age) have evidence of delayed visual system maturation that becomes normal even without treatment and of abnormal caudal brainstem development that resolves slowly with replacement therapy.(ABSTRACT TRUNCATED AT 250 WORDS)     

Pupillography refines the diagnosis of diabetic autonomic neuropathy

Although diabetic autonomic neuropathy involves most organs, diagnosis is largely based on cardiovascular tests. Light reflex pupillography (LRP) non-invasively evaluates pupillary autonomic function. We tested whether LRP demonstrates autonomic pupillary dysfunction in diabetics independently from cardiac autonomic neuropathy (CAN) or peripheral neuropathy (PN). In 36 type-II diabetics (39-84 years) and 36 controls (35-78 years), we performed LRP. We determined diameter (PD), early and late re-dilation velocities (DV) as sympathetic parameters and reflex amplitude (RA) and constriction velocity (CV) as parasympathetic pupillary indices. We assessed the frequency of CAN using heart rate variability tests and evaluated the frequency of PN using neurological examination, nerve conduction studies, thermal and vibratory threshold determination. Twenty-eight (77.8%) patients had abnormal pupillography results, but only 20 patients (56%) had signs of PN or CAN. In nine patients with PN, only pupillography identified autonomic neuropathy. Four patients had pupillary dysfunction but no CAN or PN. In comparison to controls, patients had reduced PD, late DV, RA and CV indicating sympathetic and parasympathetic dysfunction. The incidence and severity of pupillary abnormalities did not differ between patients with and without CAN or PN. LRP demonstrates sympathetic and parasympathetic pupillary dysfunction independently from PN or CAN and thus refines the diagnosis of autonomic neuropathy in type-II diabetics.     

Sensitivities of sensory nerve conduction study parameters in carpal tunnel syndrome.

It is generally accepted that median sensory nerve conduction studies are more sensitive than motor nerve conduction studies in the electrodiagnostic evidence of carpal tunnel syndrome (CTS). This study was conducted to compare the sensitivities of various parameters of sensory nerve conduction studies in the diagnosis of CTS.This prospective study included 88 consecutive patients (151 hands) with CTS and 106 control subjects. CTS was diagnosed clinically by two neurologists. Median sensory nerve responses with wrist stimulation were determined. The onset and peak latencies, peak-to-peak amplitudes, negative peak duration, and area were measured. The differences between the peak and onset latencies were also calculated as a measure of waveform temporal dispersion. Among each measured parameter, values between the 2.5th and the 97.5th percentile range of the control subjects served as the normal limits.Among the 151 hands with suspected CTS, five (3.3%) had normal electrodiagnostic studies and 146 (96.7%) had at least one abnormal electrodiagnostic study. Among the 146 hands with an abnormality, 138 had abnormal onset latency, 143 had abnormal peak latency, and 88 had abnormal difference between peak and onset latency. In addition, 87 had abnormal amplitude, 70 had abnormal duration, and 59 had abnormal area. The sensitivity was 91.4% for onset latency, 94.7% for peak latency, 58.3% for difference between peak and onset latency, 57.6% for amplitude, 46.4% for duration, and 39.1% for area.Our study shows that in patients with CTS, the most sensitive sensory nerve conduction parameter is the peak latency. Studying various additional sensory nerve conduction parameters did not significantly increase the diagnostic yield.     

Use of SEPs to localize degeneration in a rare polyneuropathy: Studies on polyneuropathy associated with pigmentation,hypertrichosis, edema,and plasma cell dyscrasia

Peripheral and central nerve conduction were studied in five patients who had polyneuropathy associated with pigmentation, hypertrichosis, edema, and plasma cell dycrasia by using the short-latency somatosensory evoked potential (SEP) to electrical stimulation of the median nerve at the wrist. The clavicular component N9 was markedly reduced inamplitude, and its latency was moderately prolonged. The interpeak latency from N9 to the cervical component N13 was significantly prolonged, indicating a conduction delay in the dorsal root. The interpeak latency from N13 to the cortical component N20 was normal, suggesting normal central conduction. These Physiological findings were consistent with the pathological findings, which showed degeneration of axons and segmental demyelination and remyelination in the sural nerve and extensive segmental demyelination and remyelination in the dorsal root but normal posterior columns of the spina cord. SEP is a noninvasive method of localizing the site of axon or myelin disorder in a peripheral neuropathy.     

Motor conduction velocity in the human spinal cord: slowed conduction in multiple sclerosis and radiation myelopathy.

Transcutaneous electrical stimulation of the central nervous system was used to measure motor conduction velocity in the human spinal cord in 21 subjects aged 22 to 75 years (mean 55 years), none of whom had neurological disease. The motor conduction velocity between the sixth cervical (C6) and first lumbar (L1) vertebral levels was 67.4 +/- 9.1 m/s. This probably represents conduction velocity in the corticospinal tracts. In these subjects the motor conduction velocity in the cauda equina, between the first lumbar (L1) and fourth lumbar (L4) vertebral levels, was 57.9 +/- 10.3 m/s. In four of five patients with multiple sclerosis, all with corticospinal signs in the legs, motor conduction velocity between C6 and L1 was slowed (41.8 +/- 16.8 m/s), but cauda equina conduction was normal (55.8 +/- 7.8 m/s). Similar slowing of spinal cord motor conduction was found in a patient with radiation myelopathy. This method should provide a relevant, simple clinical test in patients with spinal cord disease.     

Neurological risk profile in organic erectile impotence.

Thirty men who presented with erectile impotence to the urological department underwent a thorough urological, angiological, and neurological examination with complementary neurophysiological tests of somatosensory and sympathetic and parasympathetic function. Most had vascular and neurological abnormalities. Clinical findings and electrophysiological tests for autonomic dysfunction had the highest yield of abnormal results. Nerve conduction studies and pudendal nerve somatosensory evoked potentials were far less informative. The lack of correlation between vascular and general neurological abnormalities emphasises that patients must be screened for both vascular and neurological dysfunction to prevent unrewarding vascular operation in impotent men.     

Unnoticed dysautonomic syndrome of the face: Harlequin syndrome

Harlequin sign and harlequin syndrome, which are used interchangeably in the literature, are characterized by sudden onset of hemifacial sweating and flushing, induced by exercise and heat. Hemifacial sweating and flushing with normal ocular sympathetic innervation, known as harlequin syndrome, is rarely associated with tonic pupils, parasympathetic oculomotor lesion and pre- or postganglionic sudomotor sympathetic deficit. In the literature, hemifacial sweating and flushing in patients with apparently abnormal ocular sympathetic innervation has been defined as harlequin sign. To date, a few reports of excessive hemifacial sweating and flushing in structural lesion have been documented. Herein, we report five patients with excessive hemifacial sweating and flushing, two of whom had a syrinx. In presenting the patients, we have attempted to distinguish harlequin syndrome from harlequin sign. With this in mind, Case 1 can be described as harlequin syndrome resembling Ross syndrome, Case 2 as harlequin syndrome with normal ocular sympathetic innervation, Case 3 as harlequin sign with congenital Horner syndrome, Case 4 as harlequin sign with sympathetic and parasympathetic denervation sensitivity, and Case 5 as harlequin syndrome associated with occult sympathetic denervation sensitivity. These cases are discussed together with a review of the literature.     

Short-latency somatosensory-evoked potentials from radial, median, ulnar, and peroneal nerve stimulation in the assessment of cervical spondylosis. Comparison with conventional electromyography

A study of data on 30 patients with cervical spondylosis was carried out to determine whether short-latency somatosensory-evoked responses (SEPs) to median, ulnar, radial, and peroneal nerve stimulation provided additional information to that obtained by electromyography (EMG), late responses, and peripheral conduction studies. Peripheral studies, EMG results and SEPs were within normal limits in ten patients with pain, but without objective neurological deficit. By contrast, of ten patients who had objective signs of root compression, conventional EMG results were normal in nine, but abnormalities of the SEPs from radial nerve stimulation were obtained in only five patients, and were normal from ulnar and median nerve stimulation. In ten patients with clinical features of myelopathy, seven had abnormal median SEPs and all had abnormal peroneal SEPs, whereas EMG results were abnormal in only five patients. It is suggested that SEPs and EMG are both of limited use in patients with only symptoms of root compression. In patients with signs of root compression, EMG is the most sensitive procedure; however, some additional information can be obtained from superficial radial SEPs. In patients with cervical myelopathy, SEP was the most useful procedure, especially when upper and lower limbs were studied.     

Electrophysiological findings in entrapment of the median nerve at wrist and elbow

In 117 consecutive patients with carpal tunnel syndrome and 11 patients with a compression syndrome of the median nerve at elbow, motor and sensory conduction along the median and ulnar nerves and quantitative electromyography were compared with findings in 190 normal controls of the same age. In 25% of patients with carpal tunnel syndrome in whom motor conduction and EMG were normal, the lesion was located from abnormalities in sensory conduction. The fact that conduction along the same fibres was moderately slowed from digit to palm, severely slowed across the flexor retinaculum, and normal from wrist to elbow indicates that slowing was due to demyelination at the site of compression. Fifteen per cent of the patients with carpal tunnel syndrome had clinical and electrophysiological signs of ulnar involvement. In the other patients conduction along the ulnar nerve was as in 100 normal controls. Compression at the elbow was located by electromyographical findings rather than by abnormalities in conduction.     

Restless legs syndrome in hemodialysis patients in India: a case controlled study

OBJECTIVE: To assess the prevalence of restless legs syndrome (RLS) in Indian patients on hemodialysis as compared to controls. METHODS: One hundred and twenty-one consecutive hemodialysis patients and 99 controls were evaluated using a standard predesigned questionnaire. The control group comprised completely normal healthy adults who were being evaluated as renal donors. Nerve conduction studies were done in those patients diagnosed with RLS. RESULTS: RLS was present in eight hemodialysis patients (6.6%) and none of the controls. Patients (87.5%) with RLS had delayed sleep onset. Nerve conduction showed evidence of sensori-motor neuropathy in five patients and a normal study in one patient. When we compared the patients with RLS to those without RLS, there was no significant difference in their age, duration of hemodialysis, hemoglobin, blood urea, creatinine, serum ferritin or use of erythropoeitin. CONCLUSIONS: The prevalence of RLS was 6.6% in patients on hemodialysis; and 0% in controls, which is much lower than that reported from the West.     

I-123 MIBG cardiac scintigraphy and autonomic test evaluation in multiple sclerosis patients

Autonomic symptoms are common in multiple sclerosis (MS) patients and may cause significant disability. The purpose of this study was to evaluate direct cardiac sympathetic denervation in MS patients with I-123 MIBG cardiac scintigraphy compared with other parasympathetic electrophysiological examinations of autonomic dysfunction. Ten patients with MS and 7 age- and sex-matched control subjects were prospectively evaluated. The neurological deficit and disability stages of the patients were rated according to the Kurtzke Expanded Disability Status Scale (EDSS). Autonomic tests included the R-R interval, Valsalva ratio and standup test. All patients and control subjects had planar and SPECT cardiac scintigraphy with I-123 MIBG injection. Seven MS patients had relapsing-remitting (R-R) type and three had secondary progressive type (SP). A pathological MIBG cardiac washout rate was found in 3/10 MS patients, all of them with SP-MS. The other seven had normal washout rates. No correlation was found between the scan and the individual parasympathetic autonomic test results. I-123 MIBG myocardial scintigraphy may detect direct disturbances of the sympathetic cardiac function in patients with MS in addition to parasympathetic dysfunction tests and can be an important additional means of assessing autonomic pathways. Determination in MS of the co-existence of autonomic dysfunction, especially the cardiac sympathetic involvement in the SP type, may aid in evaluation of disease severity and cardiac function follow-up. All departments are affiliated with the Sackler Faculty of Medicine, Tel Aviv University, Israel.     

Diphtheritic neuropathy, an analysis based on muscle and nerve biopsy and repeated neurophysiological and autonomic function tests.

A patient with diphtheritic neuropathy was investigated with repeated tests of parasympathetic and sympathetic vasomotor and sudomotor functions for one year after the onset of symptoms. Somatic nerve function was tested with nerve conduction studies and an index based on ten variables was used to follow the course of the neuropathy. Sural nerve and anterior tibial muscle biopsies were performed. A severe but shortlasting impairment of the parasympathetic vagal reflex arc was found. The recovery of this function paralleled the clinical course. Sympathetic functions were normal. The neurophysiological variables of somatic nerve function showed signs of a mainly demyelinating mixed sensory/motor neuropathy. The recovery of these variables was slow. The nerve and muscle biopsies demonstrated mild changes consistent with a mixed, demyelinating, non-inflammatory neuropathy.     

Electrodiagnostic abnormalities in 113 consecutive patients with Guillain-Barré syndrome

We performed electrodiagnostic tests on 113 consecutive patients with acute Guillain-Barré syndrome (103 within 3 weeks of onset). The most common motor conduction abnormalities were proximal conduction block alone (27%), proximal block associated with a distal lesion (27%), and generalized slowing (22%). Other combinations of abnormalities each occurred in fewer than 10% of patients. Thirty-seven percent of patients initially had normal sensory nerve conduction study results, most often in association with proximal conduction block. The characteristic early electrodiagnostic changes in Guillain-Barré syndrome were often present when cerebrospinal fluid protein concentration was still normal. Extensive early fibrillations occurred in 10 patients, 6 of whom recovered well. Patients with early generalized slowing of motor nerve conduction velocity, combined abnormalities, or low muscle action potential amplitudes in ulnar, median, and peroneal nerves generally, but not always, had poorer outcomes than patients with conduction block in one nerve segment. There was no consistent relationship between results of electrophysiologic studies and overall clinical grade or limb power, except that none of the patients with an isolated proximal block had virtual or complete paralysis in the same limb.