Reliability of resting intramuscular fiber conduction velocity evaluation.

Characterization of the least number of muscle fibers analyzed for a quick and reliable, evaluation of intramuscular fiber conduction velocity (MFCV) is of importance for sport scientists. The aim of this study was to evaluate the reliability of vastus lateralis' intramuscular MFCV measuring either 25 or 50 different muscle fibers per participant, as well as to compare intramuscular MFCV measured in 25 (C25 ), 50 (C50 ), or 140 (C140 ) muscle fibers. Resting vastus lateralis' MFCV was measured in 21 young healthy males (age 22.1±2.4 years) using intramuscular microelectrodes in different days. Test-retest reliability of MFCV's parameters was calculated for C25 and C50 , while MFCV was compared among C25 , C50 , and C140 . Significant differences of MFCV parameters were observed between C25 condition and those of C50 and C140 . The differences in MFCV values between conditions C50 and C140 were non-significant. A close correlation was found for MFCV between C50 and C140 (r=0.884-0.988, P=.000). All reliability measures of MFCV measured with 50 fibers were high (eg, ICC=0.813-0.980, P=.000), in contrast to C25 (eg, ICC=0.023-0.580 P>.05). In conclusion, an average of 50 different fibers per subject is sufficient to provide a quick and reliable intramuscular evaluation of vastus lateralis MFCV.

Electrodiagnosis and muscle biopsy in asymptomatic hyperckemia.

Purpose/aim of the study: An increased serum level of creatine kinase (CK) in asymptomatic individuals is a diagnostic challenge, as it may be associated with either physiological conditions, such as exercise or even signal an ominous neuromuscular disease at a presymptomatic stage. The electromyogram (EMG) and the muscle biopsy play a key role in the evaluation of asymptomatic hyperckemia. The objective of this study was to investigate asymptomatic individuals with increased CK levels. MATERIALS AND METHODS: We comparatively studied EMG, quantitative EMG and muscle biopsy in asymptomatic clinically normal individuals with repeatedly increased CK levels. RESULTS: Conventional EMG was abnormal in 76% of patients, while quantitative EMG showed abnormal results in 88.9%. Muscle biopsy was diagnostic in 28%, one patient had neurogenic findings, 40% showed non-specific changes and 28% had normal results. CONCLUSIONS: EMG and especially quantitative EMG are highly sensitive in detecting subclinical neuromuscular diseases, whereas muscle biopsy may better contribute in the final diagnosis. No strong correlations were found between histological abnormalities and electrophysiological data, but further research is needed.

Anti-myelin-associated glycoprotein polyneuropathy coexistent with CREST syndrome.

Clinical involvement of the peripheral nervous system in the calcinosis cutis, raynaud's phenomenon, esophageal dismotility, sclerodactyly and telangiectasia (CREST) variant of systemic sclerosis occurs infrequently and is characterized by axonal degeneration due to necrotizing vasculitis. We report a female patient with a known history of CREST syndrome, which developed a slowly progressive, distal symmetric demyelinating sensorimotor polyneuropathy (PN), with tremor and ataxia as prominent features, compatible with anti-myelin associated glycoprotein (MAG) PN. The diagnosis of PN was established by the presence of monoclonal immunoglobulin M anti-MAG antibodies (Thin-Layer Chromatography, Western Blot and enzyme-linked immunoabsorbent assay). Given the evidence that in CREST activation of T-helper cells is observed and that anti-MAG antibodies, despite the fact that they are T-cell-independent, may be influenced by an increase in T-helper function, the coexistence of these two rare autoimmune disorders in the same patient may not be incidental but related to the underlying immunological mechanisms involved.

Churg-Strauss syndrome complicated by neuropathy: a clinicopathological study of nine cases.

OBJECTIVE: The purpose of this study was to investigate the clinical, electrophysiological and pathological features of Churg Strauss syndrome (CSS) neuropathy. METHODS: Biopsies were selected from over 700 sural nerve biopsies. The diagnosis of vasculitis was based on established clinicopathological criteria. Complete laboratory, clinical, electrophysiological and pathological studies were performed in all cases. RESULTS: Nerve biopsies of 9 patients were diagnosed as Churg-Strauss syndrome. The pathological features were vasculitis with predominant axonal degeneration and a varying pattern of myelinated fiber loss. The vasculitic changes were found mainly in small epineural blood vessels. Mononeuritis multiplex and distal symmetrical and asymmetrical sensorimotor neuropathy, were equally frequent. CONCLUSION: We conclude that, Churg-Strauss syndrome complicated frequently with polyneuropathy, and as remission depends on immunosuppressive therapy, it is important to recognize it in the early stage. The diagnosis of polyneuropathy is based on clinical and electrophysiologic studies, but precise histology, immunolohistochemistry and morphometric study of the peripheral nerve biopsy may be decisive in establishing the diagnosis.

Repetitive nerve stimulation of facial and hypothenar muscles: relative sensitivity in different myasthenia gravis subgroups.

AIM: To assess the utility of repetitive nerve stimulation (RNS) in facial and hypothenar muscles in the clinical groups of myasthenia gravis (MG). PATIENTS AND METHODS: We performed RNS study in the orbicularis oculi (O.O.), nasalis and abductor digiti quinti (ADQ) in 115 consecutive myasthenic patients and classified them according to the classifications of the Myasthenia Gravis Foundation of America. Patients were classified into three groups: group 1, group 2 (IIa, IIIa and IVa) and group 3 (IIb, IIIb and IVb). RESULTS: RNS was abnormal in 95 patients (82.6%): 78.3% in the O.O., 66.1% in the nasalis and 19.1% in the ADQ. Both facial muscles were statistically more sensitive than the ADQ in all groups of patients. RNS in the O.O. was more frequently abnormal than in the nasalis only in group 1. Sensitivity to acetylcholine antibodies in myasthenic patients was 84%. Acetylcholine receptor (AChR) and muscle-specific tyrosine kinase antibodies were present in 96.7% of the patients with abnormal RNS in both facial muscles. Single-fiber electromyogram (SFEMG) was abnormal in 91.3% of the tested patients. One of the three tests used for the diagnosis of MG (AChR antibodies, SFEMG, RNS) was abnormal in 99.1% of the patients. DISCUSSION: O.O. is the most sensitive muscle in all groups of MG followed by nasalis, while the ADQ is the muscle with the lowest sensitivity. Facial muscles, especially the O.O., should be the first to be tested in MG. The negativity of all tests (RNS, AChR antibodies, SFEMG) should question the diagnosis of MG, even in the presence of symptoms consistent with MG.

Central motor and sensory pathway involvement in an X-linked Charcot-Marie-Tooth family.

UNLABELLED: The aim of the present study was to investigate the subclinical involvement of the central nervous system (CNS) in an X-linked Charcot-Marie-Toth (CMTX) family. MATERIAL AND METHODS: Seven subjects, all members of one family with a C.462T > G connexin 32 (Cx32) mutation were investigated by Blink reflex, Somatosensory evoked potentials (SEP) and Transcranial magnetic stimulation (TMS). There were five clinically symptomatic for CMT neuropathy (four male and one female) and two asymptomatic (female) subjects. RESULTS: Subclinical CNS involvement was observed in all, symptomatic and asymptomatic subjects. CONCLUSION: This is the largest CMTX neuropathy family investigated for CNS involvement. Electrophysiological involvement of the CNS in every examined member of this family was observed, raising the question of a more systematic involvement of the CNS in CMTX disease.

Early detection of subclinical HIV sensory polyneuropathy using intraepidermal nerve fibre density quantification: association with HIV stage and surrogate markers.

The linear intraepidermal nerve fibre density (IENFD) and secondary branching were evaluated from skin biopsy of both the distal calf and the proximal thigh after staining with protein gene product 9.5 in 94 individuals of an HIV outpatient cohort. Possible correlations with clinical and electrophysiological evidence of distal sensory polyneuropathy (DSP), patients' demographics, antiretroviral history and HIV surrogate markers were analysed. Reduced IENFD was recognized in the majority of this population (mean +/- standard deviation [SD] IENFD in the calf and the thigh was 3.19 +/- 1.91 and 7.07 +/- 3.5 fibres/mm, respectively). One-third of the patients with low IENFD had no clinical or electrophysiological evidence of DSP. The level of prior immunosuppression as expressed by lower nadir CD4 count, more advanced HIV stage and prior exposure to combinations of neurotoxic antiretrovirals was associated with more decreased IENFD. Increased SB was associated with symptomatic DSP.

Polyneuropathies in teenagers: a clinicopathological study of 45 cases.

The aim of the present study was to investigate the causes of polyneuropathy in teenagers and to describe some characteristic clinical, laboratory, electrophysiological and pathological features. Forty-five patients with peripheral nervous disorders aged 13-19 were studied. Hereditary polyneuropathy of different types was diagnosed in 28 patients (62%); nine showed chronic inflammatory demyelinating polyneuropathy (CIDP) and two showed vasculitic neuropathy. In two more cases polyneuropathy was attributed to toxic agents, while among the rest, one was diagnosed as metachromatic leucodystrophy (juvenile type), one as adrenoleucodystrophy, one as porphyric neuropathy and one as Fabry disease. The high incidence of hereditary neuropathies in teenagers differs from that in adults, but is similar to that encountered in children. In our study, CIDP appears to be a frequent cause of neuropathy in teenagers, while the other causes are broadly similar to those found in studies concerning children rather than adults.

Distal sensory polyneuropathy in HIV-positive patients in the HAART era: an entity underestimated by clinical examination.

The aim of this study was to determine the prevalence of distal sensory polyneuropathy (DSP) in our HIV-positive patients under highly active antiretroviral therapy (HAART) and to investigate correlations with clinical, laboratory and demographic factors. One hundred consecutive HIV-positive patients underwent clinical and electrophysiological evaluation for DSP. Correlations with HIV stage, CD4 count, nadir CD4 count, viral load (VL), disease duration, age, sex and type of antiretrovirals were examined. Thirty-six percent of the patients had DSP (13% clinical, 23% subclinical diagnosed by electrophysiology). The prevalence of DSP was affected in a statistically significant manner by the diagnosis of AIDS (P = 0.00033), age (P = 0.0102), nadir CD4 count (P = 0.0087) and exposure to two neurotoxic antiretrovirals (P = 0.0189). Advanced HIV stage, sex, time from diagnosis, current CD4 count and VL did not seem to affect the prevalence of DSP. Clinical examination plus electrophysiology reveals that DSP affects 36% of patients under HAART, although subclinical in 2/3 of cases. Age, severe prior immunosuppression and the combined use of zalcitabine (ddC), stavudine (d4T) and didanosine (ddI) are important risk factors.

Denervation pattern of three mimic muscles in Bell's palsy.

OBJECTIVE: To explore the presence and grade of denervation in three mimic muscles in facial nerve palsy. METHODS: The frontalis, orbicularis oculi (OO), and mentalis muscles were explored in 54 patients with Bell's palsy, after 30 days from the beginning of symptoms. Concentric needle electromyography, including fibrillation detection, was performed in the three muscles on the affected side. Compound muscle action potentials (CMAP) were recorded on both sides and a CMAP ratio was calculated from each muscle. The House-Brackman scale was used to assess the initial clinical evaluation and the follow-up until recovery. RESULTS: Fibrillation was recorded in 32 patients on the 30th day after the onset and was present in 100% of mentalis and in 90% of frontalis, but in only 34% of OO, a statistically significant difference. The grade of fibrillation in OO was also statistically lower from those in the other two muscles. The 32 patients were grouped according to the presence (A) or not (B) of fibrillation in OO. In group A, CMAP ratios (affected/normal side) did not differ significantly among the three muscles. However, in group B they were significantly greater in OO and frontalis than in mentalis. In between-group comparison, group B muscles had significantly higher CMAP ratios, lower degree of fibrillation, and better functional recovery. CONCLUSION: In facial palsy, the presence and grade of fibrillation in OO are lower than in frontalis and mentalis muscles and prognosis is more favorable for the non-fibrillating OO group of patients.

Ulnar Neuropathy at the Elbow in Chronic Alcohol-Dependent Subjects.

OBJECTIVES: To evaluate the occurrence of Ulnar neuropathy at the elbow (UNE) among alcohol dependent subjects. METHOD: The study sample comprised 99 consecutive alcohol dependent subjects treated for detoxification voluntarily in the specialized unit of the Athens University Psychiatric Clinic in an inpatient basis. RESULTS: UNE was found in 51 subjects (51.5%): in 40.4% on the right side, in 44.6% on the left and in 20.1% on both. Polyneuropathy was diagnosed in 41.4% of the total sample. Statistical analysis showed UNE significantly associated with age of the subjects, age at alcohol dependence onset and duration of alcohol dependence. Was more frequent in men and the probability of UNE was lower in obese subjects. CONCLUSIONS: UNE is frequent among alcohol dependent subjects and they must be instructed to avoid abnormal postures and to protect their elbow while working with the elbows flexed and resting on a hard object.

Patients with ocular symptoms referred for electrodiagnosis: how many of them suffer from myasthenia gravis?

The aim of this study was the diagnosis of patients with isolated ocular manifestations (ptosis and/or diplopia) referred for electrophysiological evaluation to the electrodiagnostic laboratory of a University Neurological Department. Examination was performed either in inpatient status or in outpatient basis. We analyzed the clinical, electrophysiological and other laboratory data in 79 subjects. Myasthenia gravis (MG) was diagnosed in 38 %, 45.6 % in other diseases (Graves disease, blepharospasm, IIId cranial verve palsy, multiple sclerosis, stroke, etc.), while in 16.5 %, the cause remained unidentified. Symptoms fluctuation was significantly more frequent in the myasthenic patients, compared to patients with other diseases. The presence of both diplopia and ptosis are more likely due to MG rather than other pathology.

Hereditary neuropathy with liability to pressure palsies: the same molecular defect can result in diverse clinical presentation.

Hereditary neuropathy with liability to pressure palsies (HNPP) is a peripheral nerve disorder characterized by autosomal dominant inheritance, recurrent pressure palsies, reduced motor and sensory conduction velocities and sausage-like swellings (tomacula) of myelin sheaths in nerve biopsy. Two young adult patients are reported as index cases of two families in which HNPP was diagnosed. The first patient presented with recurrent pressure palsies, whereas the second suffered from fasciculations and myokymias in his right hand, with difficulty in writing, and upper and lower limb paraesthesias of 3 years' duration. Electrodiagnostic studies revealed slowing of conduction primarily in common sites of compression in both patients. Sural nerve biopsy revealed the characteristic tomaculous swellings in both patients. DNA analysis showed that both patients have a deletion in chromosome 17p11.2 which is found in the majority of HNPP cases. In light of the common molecular defect, the different clinical symptomatology of the two patients is discussed.

Differential presence of fibrillation in mimic muscles in Bell's palsy.

The presence of fibrillation in mimic muscles in Bell's palsy was investigated during a clinical and electrophysiological follow-up study. Fibrillation was present in 58,82% of the frontalis and mentalis, but only in 29,41% of the orbicularis oculi (OO) muscles tested. Furthermore, the amount and the time course of fibrillation were also different, without any significant differences concerning the EMG pattern among the three muscles. The compound muscle action potential (CMAP) of the OO was negatively correlated with the presence of fibrillation. The recovery of OO was slightly better than that of the others muscles. An attempt of interpretation of these findings is made on the line of a possible sparing of the OO nerve fibers and the unique histochemical properties of the OO. On these grounds, fibrillation in the OO in Bell's palsy is less frequent than as in the other mimic muscles, and its absence is not necessarily indicating a good prognosis.

The tendon reflexes in the electrodiagnosis of sciatica.

In order to determine the diagnostic value of the electromyographically tested tendon reflexes (ETR) in lumbosacral radiculopathies, we compared the latency and amplitude of the knee (EKTR) and Achilles tendon reflex (EATR) to their clinical testing and to the EMG and H reflex values in 200 non selected patients (126 men, 74 women) aged 24-68 years (48.6 +/- 9.4). The control group was composed of 50 healthy volunteers (28 men, 22 women) aged 25-60 yrs (44 +/- 8.5). The combined electrophysiological reflex examination was abnormal in 45% of the affected limbs, being the most frequent pathological finding. EMG was abnormal in 34.4% and H reflex in 30.4% of the affected limbs. Furthermore, the EATR taken separately was more sensitive than the H-reflex (42.8% versus 30.4%). Pathological ETR were elicited in a considerable percentage of the clinically normal tendon reflexes (TR): 7.3% of the knee and 14.1% of the Achilles TR. On the other hand 65% of the clinically absent ATR were recorded electrically producing abnormally low and delayed muscle evoked potentials.

Lambert-Eaton myasthenic syndrome. Clinical and electrophysiological findings in seven cases.

We report the clinical and electrophysiological findings in seven patients with Lambert-Eaton myasthenic syndrome (LEMS). All patients were males aged 40-73 years old. Six presented proximal muscle weakness and one both proximal and distal. The tendon reflexes were absent in four patients, depressed in two and normal in one patient. Three patients presented ophthalmic and four autonomic symptoms. The syndrome was diagnosed 3-12 months after the onset of symptoms in six patients and 4 years later in one. Acetylcholine receptor antibodies were negative in all patients. Voltage-gated calcium channel antibodies (VGCC) were measured in five patients and were positive in four. All patients had low compound muscle action potential (CMAP) at rest, a decrement in CMAP amplitude of 20-47% at 3 Hz repetitive nerve stimulation, and an increment of 200-700% at 40 Hz. In three patients the syndrome was associated with histologically verified small-cell lung cancer (SCLC). In the younger patient (40 years old), a lymph node biopsy performed nine years before the diagnosis of LEMS, had shown an atypical microcellular cancer of undetermined origin, which was treated with chemotherapy. LEMS 9 years after the diagnosis of cancer has not been described previously. The fifth patient had a two years history of bladder cancer (grade II). Three years after the diagnosis of LEMS he presented chronic lymphogenic leukemia. No malignancy was found in the remaining 2 patients.

Electrophysiological recording of tendon reflexes in cervical myelopathy.

Twenty-six patients with unequivocal, clinically and radiologically confirmed cervical myelopathy were investigated electrophysiogically using needle electromyography (EMG), motor and sensory conduction velocity, F-wave latency and the electromyographic recording of the tendon reflexes (TR) of the biceps brachii, brachioradialis and triceps brachii muscles. Normal latency and amplitude values of the reflex evoked compound muscle potentials (T-wave) were calculated from 74 healthy volunteers. Pathological TR were found in 73.1% of the patients, while EMG--which was the next more effective method--was positive in 38.5% of the cases. Eight pathologically delayed T-waves were recorded from muscles with clinically normal or even exaggerated reflexes. TR recording appears to be a useful method in the assessment of segmental functional disturbance in cervical myelopathy.

Sensory nerve conduction studies of the less frequently examined nerves.

The normal values of latency, amplitude and conduction velocity of the sensory nerve action potentials of a group of infrequently or even rarely examined nerves, are reported. A number of preliminary testings was made in order to establish the most appropriate and practical stimulation and recording procedures for the study of the axillary, lateral antebrachial cutaneous, medial antebrachial cutaneous, lateral femoral cutaneous, saphenous, superficial peroneal and medial plantar nerves. The examination techniques and the normal data obtained from their application on 30 healthy subjects, 20 to 36 years of age, at constant skin temperature, are discussed and compared to those already existing in the available literature.

The effect of Jendrassik manoeuvre on the latency, amplitude and left-right asymmetry of tendon reflexes.

In order to determine the effect of the Jendrassik manoeuvre (JM) on the latency and amplitude of the electrically recorded compound action potentials of the tendon reflexes (TR) as well as on their left-right asymmetry, the above parameters of the knee (KR) and Achilles (AR) TR were measured in 52 normal subjects (32 men and 18 women) aged 18-74 years (33 +/- 12.2) both at rest and during the JM, using a commercially available tendon hammer connected with the electromyograph. The left-right difference of the latencies was not statistically significant under both conditions. The knee reflex latency--on both sides--was shortened during the JM, while that of the Achilles tendon reflex was not significantly altered. The difference of the TR amplitude between the two sides in percentage of the lower value was not significant at rest and showed a marked diminution during JM. The manoeuvre caused also a net increase of the absolute values of the compound action potentials amplitude of both reflexes.