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.     

Progressive sensory nerve dysfunction in amyotrophic lateral sclerosis: a prospective clinical and neurophysiological study

Sensory nerve function was determined in 19 patients with amyotrophie lateral sclerosis (ALS), using a battery of clinical and neurophysiological tests. This assessment was repeated on 12 patients after intervals of 6–18 months. Twelve controls were also studied. In the ALS group, only 2 patients had noticed mild sensory symptoms and none had sensory signs. Between successive studies the vibration thresholds increased, but not to a significant degree. ALS patients showed a significant fall in amplitude of the sensory nerve action potentials in the median, radial, and sural nerves (P < 0.04); sensory nerve conduction velocity did not alter. The median nerve somatosensory evoked potential N19 latency showed a highly significant increase (P < 0.008). Significant subclinical deterioration in sensory nerve function occurs in ALS, and parallels the progressive motor decline. Neuronal degeneration in ALS is not restricted to motor neurons.     

Vasculitis-like neuropathy in amyotrophic lateral sclerosis unresponsive to treatment

Amyotrophic lateral sclerosis (ALS) is a fatal motor neuron disease with variable involvement of other systems. A pathogenetic role of immune-mediated mechanisms has been suggested. We retrospectively analyzed sural nerve pathology and the clinical course in 18 patients with ALS. These patients had undergone sural nerve biopsy because of clinical or neurophysiological signs indicating sensory involvement (ALS+). Eleven of the 18 ALS+ patients had inflammatory cell infiltrates (ALS_vasc) resembling infiltrates seen in patients with vasculitic neuropathy. Data were compared with the 7 patients without vasculitic infiltrates (ALS_nonvasc) and with those of 16 patients with isolated peripheral nerve vasculitis (NP_vasc). Biopsy specimens were processed with standard histological stains and with immunohistochemistry for a panel of inflammatory markers, with the hypothesis that the composition of infiltrates should differ between ALS_vasc and NP_vasc. Immunoreactive cells were quantified in a blinded manner. Unlike patients with NP_vasc, those with ALS_vasc had only minor neurophysiological abnormalities in the sural nerve and, except for the infiltrates, almost normal nerve morphology on semithin sections. The difference in epineurial T cell count was significant between ALS_vasc and ALS_nonvasc (p = 0.031). Surprisingly, the cellular composition of epineurial infiltrates in sural nerve biopsies was indistinguishable between ALS_vasc and NP_vasc despite a significant difference in fiber pathology (p < 0.0001). Standard immunosuppressive treatment did not prevent clinical progression of the motor neuron disease in any of the patients with ALS_vasc. ALS_vasc appears as a neuropathological subtype in ALS+ suggesting immune-mediated disease components but without response to standard immunosuppressive treatment.     

Electrophysiological studies in diabetic neuropathy

In 30 patients with diabetic neuropathy sensory potentials in the median nerve, motor conduction in the lateral popliteal and median nerves, and electromyographic findings in distal and proximal muscles were compared with the severity of symptoms and signs. All patients had abnormalities in at least one of the electrophysiological parameters. The sensory potentials were the most sensitive indicator of subclinical involvement; abnormalities were found in 24 patients, 12 of whom had no sensory symptoms or signs and five of whom had no other clinical or electrophysiological evidence of neuropathy in the upper extremities. This indicates that sensory nerve fibres may be affected before motor. The next most sensitive parameter was the presence of fibrillation potentials, found in more than half the distal muscles examined. Slowing in motor conduction in the lateral popliteal nerve was the only electrophysiological change correlated to the severity of the neuropathy, and no other electrophysiological parameter was correlated to the duration or the severity of the neuropathy or the diabetes. An onset of neuropathy before or simultaneously with the manifestations of the diabetes, as well as the frequent occurrence of asymptomatic changes in sensory conduction, support the evidence at hand that the neuropathy develops concomitantly with and as an integral part of the metabolic disturbance rather than as a consequence of the vascular complications of diabetes. Of three patients with clinical signs or symptoms of a diabetic amyotrophy, two had asymptomatic electrophysiological abnormalities in distal nerves and muscles, consistent with widespread involvement of the peripheral nerves. The third patient had electromyographic changes in the medial vastus muscles suggestive of a myopathy. Motor and sensory conduction in distal and proximal nerves were normal.     

Motor unit involvement in human acute Chagas' disease

Thirty five patients with acute Chagas' disease who demonstrated parasitaemia at the time of the investigation were submitted to a detailed electromyographical study. With their muscles at rest, 12 patients showed fibrillation potentials and/or positive sharp waves. On volitional contraction, 7 had short duration motor unit potentials (MUPs) and low polyphasic MUPs. On motor and sensory nerve fibers conduction studies, 20 disclosed values below the lower control limit within one or more nerves. Finally, 12 patients produced a muscle decremental response on nerve supramaximal repetitive stimulation. The findings signal that primary muscle involvement, neuropathy and impairement of the neuromuscular transmission, either isolated or combined, may be found in the acute stage of human Chagas' disease.     

Peripheral neuropathy in myotonic dystrophy type 1

Myotonic dystrophy 1 (DM1) is characterized by a wide range of clinical features. We aimed to verify the presence of peripheral nerve involvement in a large cohort of DM1 patients and to determine clinical consequences. A total of 93 patients underwent detailed neurological examination and nerve conduction studies. Additionally, balance impairment was assessed with the Berg Balance Scale and health status was evaluated with the SF-36 health survey. Sensory symptoms were not reported and mild sensory signs were found in six patients. Electrophysiological abnormalities consistent with a diagnosis of neuropathy were found in 16 patients (17%). Peripheral nerve involvement was significantly associated with decreased muscle strength (p = 0.001) and absence of Achilles-tendon reflexes (p = 0.003), but not with age or duration of neuromuscular symptoms. It had no significant effect on balance, mental or physical health. In conclusion, peripheral nerve involvement may be one of the multisystemic manifestations of DM1, but is usually subclinical. Other causes should be excluded when sensory symptoms or signs are severe.     

Motor nerve impairment in diabetic patients with symmetrical distal sensory polyneuropathy: A single nerve fiber conduction velocity study

Introduction: In this study we investigated the clinical utility of single fiber conduction velocity (SF‐CV) testing in the evaluation of motor nerve function in diabetic patients with signs and symptoms of symmetrical distal sensory polyneuropathy (DSP). SF‐CV findings were compared with conventional nerve conduction studies (NCS). Methods: Twenty‐eight consecutive type 2 diabetic patients with clinically diagnosed DSP were studied. Results: SF‐CV testing of the tibial nerve was abnormal in 16 (57.1%) patients. Twelve patients with normal conventional motor NCS had abnormal findings by tibial SF‐CV. SF‐CV testing of the tibial nerve was significantly superior to all other motor NCS. Conclusions: SF‐CV testing of the tibial nerve often demonstrates motor nerve impairment in diabetic patients with sensory DSP when conventional NCS are normal. Muscle Nerve 49 : 84–89, 2014     

Unusual neurophysiological features in Cockayne's syndrome: a report of two cases as a contribution to diagnosis and classification

To clarify the diagnostic value of neurophysiological investigations in patients with Cockayne's syndrome (CS). The study involved two patients with clinical diagnoses of classical and severe CS, who were neurophysiologically evaluated by means of: (1) multimodal visual (VEPs), brainstem auditory (BAEPs) and upper limb somatosensory (SEPs) evoked potentials; (2) electroretinography; and (3) nerve conduction and needle electromyography studies. Both patients showed multimodal evoked potential (EP) signs of central nervous system involvement that overlapped in severity and extent, and were consistent with demyelination along the central sensory pathways. Flash VEPs and SEPs were more altered than pattern VEPs and BAEPs. No signs of retinopathy or hearing loss of cochlear origin were detected. The nerve conduction and needle electromyography studies showed severe signs of sensory and motor demyelinating and axonal peripheral neuropathy. Peripheral neuropathy was clinically uncertain. There were no significant differences between the two patients. Our results show that combined multimodal EP and nerve conduction studies are diagnostically highly sensitive even in the early stage of CS, but their ability to distinguish classical and severe CS is limited. The unusual features were characterised by the absence of clinical and electrophysiological signs of otherwise common retinopathy and neurosensory hearing loss. BAEPs seem to be more useful than VEPs or SEPs in the diagnostic work-up of patients with suspected CS.     

Etiology of small-fiber neuropathy

The aim of this study was to evaluate the etiology in a group of 84 patients with painful sensory neuropathy with predominant small-fiber dysfunction (54 men and 30 women, median: 58; range: 25–83 years) recruited from a population of the South Moravian region of the Czech Republic. Involvement of small nerve fibers was verified by abnormal thermal thresholds and/or reduced intraepidermal nerve fiber densities. Motor signs or symptoms or significant clinical signs of sensory large-fiber involvement were exclusionary; 33 patients, however, had sensory nerve conduction abnormalities. For comparison, the prevalence of risk factors was assessed in a group of 47 asymptomatic age- and sex-matched controls (30 men and 17 women, median: 59; range: 29–85 years). The multivariate regression model disclosed that diabetes mellitus (odds ratio [OR] = 4.08), chronic alcoholism (OR = 5.31), and serum cholesterol levels (OR = 4.51) were the only parameters independently associated with small-fiber involvement. No possible etiology was detected in 19 patients (22.6%). In conclusion, the spectrum of risk factors and proportion of idiopathic cases in geographically defined small-fiber polyneuropathy sample is similar to that referred in large-fiber polyneuropathy.     

Peripheral neuropathy associated with polycythemia vera

Nerve conduction studies were performed on 26 patients with polycythemia vera, 11 of whom had sensory symptoms in the extremities and 3 of whom had clinical signs of peripheral neuropathy. There was significant impairment of sensory conduction in the ulnar and sural nerves and mild slowing of motor conduction in the lateral popliteal nerve. Sural nerve biopsies were performed on three patients. The pathological findings, including teased fiber studies, were consistent with mild chronic axonal degeneration. There is an association between polycythemia vera and peripheral neuropathy.     

Neuropathies and almitrine. 14 cases

Previously reported cases of peripheral neuropathies occurring during almitrine therapy had only a few weeks follow-up after having stopped the drug. We have studied clinical and electrophysiological data 6 to 12 months after almitrine had been given up in 9 patients from a group of 14 whose epidemiologic, clinical, electrophysiological and pathological data had been registered. In 7 of them, without any chronic respiratory deficiency, almitrine was administered as almitrine bismésilate and raubasine, and in 7 others (6 with chronic respiratory deficiency) as almitrine bismesilate alone. In patients who had another possible cause of neuropathy, clinical disorders appeared after a lesser total quantity of almitrine (p less than 0.05). Clinical data were suggestive of sensory peripheral neuropathies of feet and lower third of legs. Electrophysiological data suggested distal axonopathy in spite of the absence of denervation: amplitudes of sensory potentials were reduced and nerve conduction velocities were moderately decreased. Biopsies revealed mild neurogenic atrophy of muscles and distal axonopathy. Clinical improvement was very slow and 6 to 12 months later, most of the patients still presented decreased vibration sense and ankle reflexes loss, but all of them were still improving. Amplitudes of sensory potentials and sensory nerve conduction velocities were significantly improved (p less than 0.05) but motor nerve conduction velocities were not (p greater than 0.05). Our study shows: 1) clinical, electrophysiological and pathological data similar to those previously reported; 2) subclinical disturbances of motor functions in lower limbs and sensory functions in upper limbs; 3) some patients presented with unusual signs: posture tremor (3 cases), painful legs and moving toes (1 case); 4) peripheral neuropathies may occur during almitrine therapy even in patients without any chronic respiratory insufficiency; 5) peripheral neuropathies occurred with lower doses in patients with other factors predisposing to neuropathies; 6) patients' improvement was very slow; 7) in 9 cases the imputability of these peripheral neuropathies to almitrine is plausible. We suggest not to prescribe almitrine without caution, especially in patients with other factors of neuropathy. Treatment should be regularly interrupted.     

Comparison of IgM-MGUS and IgG-MGUS polyneuropathy

Objective – To compare the clinical and electrodiagnostic features and response to treatment in patients with IgM-MGUS and IgG-MGUS associated polyneuropathy. Material and methods – Retrospective review of 34 consecutive patients with MGUS associated neuropathy evaluated over 5 years. Results – There were 19 patients with IgM-MGUS and 15 with IgG-MGUS. There were no differences in age, duration of symptoms, or distribution of motor and sensory symptoms or signs. IgM-MGUS patients had prolonged distal latencies of the median and ulnar motor potentials, greater slowing of the peroneal nerve conduction velocity and more often absent ulnar sensory potentials. Half of the patients in both groups improved following immunotherapy. Conclusion – IgM-MGUS patients had more severe dernyelination on the nerve conduction studies, but there were no clinical features that differentiated the 2 groups. IgM and IgG-MGUS patients improved with plasma exchange and other immune therapies. Anti-MAG antibodies failed to distinguish a subgroup of patients with IgM-MGUS neuropathy     

Chronic idiopathic axonal polyneuropathy and successful aging of the peripheral nervous system in elderly people

BACKGROUND: Chronic idiopathic axonal polyneuropathy (CIAP) is a frequent neurologic disorder in elderly persons. In view of the aging population, it is important to know the long-term prognosis of CIAP. OBJECTIVES: To determine if CIAP is influenced by the superposition of the effects of aging and to evaluate the severity of CIAP according to the disease duration. DESIGN: Controlled cohort study. SETTING: Outpatient clinic for neuromuscular diseases at the University Medical Center Utrecht, Utrecht, the Netherlands. PARTICIPANTS AND METHODS: One hundred twenty-seven patients with CIAP and 108 age-matched control subjects were included. We defined CIAP on the basis of symmetrical distal sensory or sensorimotor symptoms and signs with evolution over at least 6 months, exclusion of causes by history taking, results of clinical and laboratory investigations, and electrophysiologic findings that agreed with the diagnosis of axonal polyneuropathy. RESULTS: No important neurologic or electrophysiologic differences were found between patients with early-onset (before the age of 65 years) and late-onset (at or after the age of 65 years) CIAP, but patients with early-onset CIAP who had a short disease duration (<10 years) experienced more disability than patients with late-onset CIAP who had a similar disease duration. Old controls (age of 65 years or older) more often had symptoms, sensory signs in the legs, absent ankle jerks, and lower mean distal amplitudes of compound muscle action potentials and sensory nerve action potentials than young controls (aged <65 years). Absence of the sural nerve sensory nerve action potentials or presence of spontaneous muscle fiber activity in the anterior tibial muscle was common in patients with CIAP (51% and 60%, respectively), but exceptional (both 2%) in controls. CONCLUSIONS: Neither aging of the peripheral nervous system nor disease duration affects CIAP to a considerable degree, but CIAP has a greater influence on the daily life of nonretired patients with early-onset CIAP. The diagnosis of axonal polyneuropathy is probably supported best by either the absence of the sural nerve sensory nerve action potentials or the presence of spontaneous muscle fiber activity in the anterior tibial muscle.     

Clinical and electrophysiologic study of the peripheral nerve in 28 cases of mitochondrial disease]

Twenty-eight patients with mitochondrial disease were systematically investigated on clinical and electrophysiological grounds for peripheral neuropathy (PN): 25 had predominant ophthalmoplegia (including 4 with Kearns-Sayre syndrome) and 3 had predominant central nervous system involvement. There were 11 men and 17 women, mean age 43 years. Nine of the 28 patients had signs of sensory polyneuropathy involving mainly the lower limbs. These 9 patients and another asymptomatic patient had electrophysiological abnormalities: in the lower limbs, sensory potentials were absent or decreased in amplitude in all cases. In peroneal nerves, motor conduction nerve velocities were decreased in 4/10 cases. These data were consistent with an axonopathy. No correlation was found between the presence of PN and the clinical features of the mitochondrial diseases or with the respiratory chain defect (studied in 14 cases).     

Electrophysiological findings in a Danish family with Machado-Joseph disease

Machado—Joseph disease (MJD) is a neurodegenerative disorder with autosomal dominant inheritance. We have carried out electrophysiological studies in 8 individuals belonging to a Danish family with several affected members. Five had an expanded trinucleotide (CAG) repeat sequence in the MJD1 gene on chromosome 14, indicating MJD, while 3 unaffected individuals had normal repeat lengths. Three individuals with repeat expansion had clinical symptoms and signs of the Machado or “type III” phenotype, whereas 2 had slight symptoms and signs only. Electrophysiological evaluation included visual, somatosensory, and auditory brain stem evoked potentials, quantitative electromyography, and nerve conduction studies. In the patients with clinical MJD, evoked potential studies showed multimodal abnormalities, electromyography showed neurogenic changes, and nerve conduction studies showed signs of severe loss of motor and sensory nerve fibers. Of the 2 patients with slight symptoms and signs, 1 had evidence of peripheral and central affection, while the other had slight signs of a central affection. This study provides insight into the distribution and character of electrophysiological abnormalities in MJD of putative importance for an understanding of the pathogenesis of the disease, and for monitoring disease progress or the outcome of a possible treatment. © 1996 John Wiley & Sons, Inc.     

Central and peripheral SEP defects in neurologically symptomatic and asymptomatic subjects with low vitamin B12 levels

Somatosensory evoked potentials (SEPs) following median nerve stimulation were abnormal in 7 patients with sensory impairment due to vitamin B12 deficiency. Extensor plantar reflexes indicated a central sensory pathway lesion in 4 cases and absent tendon jerks suggested peripheral neuropathy in 4, but median nerve SEPs indicated a predominantly central lesion without marked peripheral nerve involvement in 6 and an axonal neuropathy without CNS involvement in 1. The latter had evidence of central slowing of conduction in SEPs following posterior tibial nerve stimulation. Consequently, it is suggested that the brunt of sensory pathway involvement usually falls on the CNS, although peripheral neuropathy may occur as the major abnormality in some cases. In 2 patients SEPs showed a marked improvement following treatment with vitamin B12 injections, one consistent with restored central conduction and the other with recovery from peripheral neuropathy. No peripheral or central SEP abnormalities were seen in 18 dairy-produce eating vegetarians with low vitamin B12 levels, although 6 reported mild sensory symptoms suggestive of peripheral neuropathy and 3 had corroborative clinical signs.     

Long-term clinical and electrophysiological results of local steroid injection in patients with carpal tunnel syndrome

The aim of this study was to evaluate the effects of local steroid injection on both the clinical symptoms and motor and sensory conduction of the median nerve in carpal tunnel syndrome (CTS). Using a standard evaluation and treatment protocol, we prospectively studied steroid injection in 32 hands in 24 patients (mean age: 50.7 +/- 10 years; 23 women and 1 man). To determine the normal median nerve values, 42 normal controls (mean age: 39.1 +/- 10.5 years; 21 women and 21 men) were also studied. At follow-up, clinical symptom scores and signs of CTS, as well as electrophysiological variables of the median nerve, showed a significant trend towards improvement with respect to baseline values (p < 0.01). By the end of the one-year follow-up period, the symptoms had remitted completely or partially in 27 hands (84.4%). In addition to the relief of the symptoms, motor nerve conduction abnormalities had improved in 62.6% of hands, and anti-dromic sensory nerve conduction abnormalities in 62.5%. In cases where a sensory nerve action potential (SNAP) could be obtained, the efficacy of this treatment was found to be relatively higher than in cases in which SNAP was absent (p < 0.01).     

Hallazgos electrofisiológicos precoces en síndrome Fisher-Bickerstaff

IntroductionThe term Fisher-Bickerstaff syndrome (FBS) has been proposed to describe the clinical spectrum encompassing Miller-Fisher syndrome (MFS) and Bickerstaff brainstem encephalitis. The pathophysiology of FBS and the nature of the underlying neuropathy (demyelinating or axonal) are still subject to debate. This study describes the main findings of an early neurophysiological study on 12 patients diagnosed with FBS.Patients and methodsRetrospective evaluation of clinical characteristics and electrophysiological findings of 12 patients with FBS seen in our neurology department within 10 days of disease onset. Follow-up electrophysiological studies were also evaluated, where available.ResultsThe most frequent electrophysiological finding, present in 5 (42%) patients, was reduced sensory nerve action potential (SNAP) amplitude in one or more nerves. Abnormalities were rarely found in motor neurography, with no signs of demyelination. The cranial nerve exam revealed abnormalities in 3 patients (facial neurography and/or blink reflex test). Three patients showed resolution of SNAP amplitude reduction in serial neurophysiological studies, suggesting the presence of reversible sensory nerve conduction block. Results from cranial MRI scans were normal in all patients.ConclusionAn electrophysiological pattern of sensory axonal neuropathy, with no associated signs of demyelination, is an early finding of FBS. Early neurophysiological evaluation and follow-up are essential for diagnosing patients with FBS.     

Symptom duration and clinical features in painful sensory neuropathy with and without nerve conduction abnormalities

BACKGROUND: The term "small fiber sensory neuropathy" (SFSN) refers to an axonal sensory polyneuropathy predominantly affecting cutaneous sensory modalities, often associated with pain and with no evidence of large fiber involvement. We hypothesized that, in most patients, SFSN is the earliest manifestation of a nonspecific axonal neuropathy and will usually progress to involve larger, heavily myelinated sensory and motor fibers. We sought indirect evidence of this through an analysis of the correlation between symptom duration and large fiber involvement in patients with painful sensory neuropathy (PSN). METHODS: A clinical diagnosis of PSN was supported by nerve conduction studies or measurement of epidermal nerve fiber (ENF) density in 43 patients. Symptom duration was correlated with the frequency of large fiber loss as measured by nerve conduction abnormalities. The severity and extent of clinical signs and symptoms were also evaluated in subjects with and without electrodiagnostic abnormalities. RESULTS: Patients with large sensory axon involvement had symptoms of longer duration than patients with SFSN. The frequency of electrodiagnostic abnormalities increased in direct proportion to disease duration. Patients with electrodiagnostic abnormalities also had more extensive pinprick sensory deficits, suggesting that small fiber loss was more advanced in this group as well. CONCLUSIONS: In PSN, the incidence of large fiber involvement appears to increase in proportion to symptom duration. This represents indirect evidence that SFSN usually progresses to involve both large and small fibers within 2-10 years.     

Usefulness of electrophysiological studies in the diagnosis of lumbosacral root disease

Clinical, electrophysiological, and myelographic findings were correlated in 57 patients with the clinical diagnosis of lumbosacral root disease. Conventional motor and sensory (including sural nerve) conduction studies were normal in all patients. Electromyography, late response studies in different muscles of the lower extremity, the myelogram, or combinations of these tests were abnormal in 44 patients (77%). Of 36 patients (63%) with abnormal myelograms, 14 had normal electrophysiological studies. Twenty-nine (51%) had an abnormal electrophysiological or myelographic finding; although 8 patients in this group had a normal myelogram, 2 had an abnormal discogram and 1 an abnormal epidurogram. Electrophysiological or myelographic findings, in some cases both, correlated well with clinical signs and symptoms in 41 patients (72%). H-reflex and F response studies, when abnormal, helped in localizing a lesion in the appropriate root distribution.