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.

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.

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.

Concurrent bilateral projection and activation of motor cortices in a patient with congenital mirror movements: a TMS study.

OBJECTIVES: Mirror movements (MMs) are unintended and unnecessary movements accompanying voluntary activity in homologous muscles on the opposite side of the body, particularly in distal arm muscles. Congenital MMs may be sporadic or familial. Several mechanisms have been proposed to explain persistent congenital MMs. Hypothesis 1 assumes the existence of an ipsilateral corticospinal pathway, and Hypothesis 2 the activation of both motor cortices. We report a new case of congenital mirror movements in a healthy woman. METHODS: Electromyographic recordings and focal transcranial magnetic stimulation (TMS) were used for neurophysiological evaluation. RESULTS: Voluntary contraction of either abductor pollicis brevis (APB) elicited mirror activation of the other APB. Focal TMS of either M1 elicited motor evoked potential (MEP) of normal latency and amplitude in both resting APB. TMS of the left cortex upon maximal contraction of the right APB and mirror contraction of the left APB produced interhemispheric inhibition (IHI) in the former and silent period (SP) in the later. CONCLUSIONS: The electrophysiological evaluation using transcranial magnetic stimulation provides evidence of the concurrent action of both mechanisms in this patient. SIGNIFICANCE: The combination of more than one hypothesis could be more appropriate for understanding the underlying mechanism in some MM cases.

Nomogram for determining lower limit of the sural response.

OBJECTIVE: Age and height influence on sural sensory nerve action potential (SNAP) have been studied separately. Our aim was to develop an equation for predicting the lower normal limits as a function of both these factors. METHODS: One hundred fifty-eight healthy volunteers, 63 male, with mean age 45.8 and mean height 167.3 without symptoms or signs of peripheral neuropathy participated in the study. The sural SNAP was recorded at the level of the ankle joint, just posterior to the lateral malleolus, using surface electrodes. Antidromic supramaximal stimulation was performed 13 cm proximally at the posterior midcalf. RESULTS: The mean sural SNAP amplitude was 19.9+/-6.89 microV. Pearson linear correlation showed a negative correlation of the SNAP amplitude with age (R=-0.22, p=0.005) and height (R=-0.19, p=0.03). The multiple linear regression model was applied for both parameters of age and height with SNAP amplitude as the dependent parameter, producing the following equation: SNAP amplitude=62.45-0.1447 x Age-0.2147 x Height. CONCLUSIONS: Using our normal data, the computed lower limits of the 95% prediction interval for the sural SNAP amplitude of an individual subject, depending on his age and height, were calculated. SIGNIFICANCE: The individualized normal values provided by our equation are essential for the correct interpretation of sural nerve studies.

The two sensory branches of the superficial peroneal nerve: electrophysiological differences and correlations with gender, age, height and BMI.

AIMS OF THE STUDY: To detect amplitude differences between the sensory nerve action potentials (SNAP) obtained by simultaneous recording of the two main branches of the superficial peroneal sensory nerve (SPSN), the medial and intermediate dorsal cutaneous sensory nerves (MDCN, IDCN); to investigate whether these differences, if any, are correlated with gender, age, body mass index (BMI), and height of normal subjects; to discuss their clinical significance. POPULATION AND METHODS: Seventy-six healthy volunteers (36 males) were included (mean age: 36.5 years, range 20-80). Simultaneous MCND and IDCN recordings were performed via surface electrodes placed at precise positions on the intermalleolus line. Stimulation was performed 14 cm proximally on two different sites over the anterolateral aspect of the right leg. RESULTS: Responses were obtained for both nerve branches in all subjects. Median value and lower normal limit for the amplitude of the greater among both MDCN and IDCN responses was 10.95 microV and 4.9 microV, respectively. Statistically significant differences were found between the two branches in median amplitude and frequency of the greater value. These differences were not correlated with gender, age, BMI, or height. CONCLUSION: We propose simultaneous recording of the two main branches of the superficial peroneal sensory nerve, placing the recording electrodes and stimulation device on precise positions and measuring the amplitude of the best of both responses. This method is an improvement of an already existent one, and may be clinically useful in detecting abnormal responses of the SPSN.

Stereoanesthesia or astereognosia?

This case attempts to explicit the importance of clinical examination in the differential diagnosis of two similar clinical entities namely astereognosia and stereoanesthesia. The patient presented below involves a multiple sclerosis patient whose symptoms were considered at first to be a case of astereognosia since she mainly complained of an inability to recognize and name the form and nature of objects by touch. However, a thorough clinical examination and the results of neurophysiological and neuroimaging testing demonstrated that it involved a case of stereoanesthesia due to a demyelinating lesion at the cervical region of the spinal cord.

Superficial siderosis of central nervous system mimicking multiple sclerosis.

INTRODUCTION: Superficial siderosis of the central nervous system is a neurologic disorder mainly characterized by cerebellar involvement, myelopathy, neurosensory hearing loss, and possibly progressive cognitive impairment. Root avulsion due to traumatic plexus injury has been recognized as an extremely rare cause of hemosiderin deposition on leptomeninges and subpial layers of brain and spinal cord parenchyma. CASE REPORT: A 49-year-old man presented with progressively evolving ataxia and spastic paraparesis. CSF oligoclonal bands were indicative of an underlying inflammatory process and raised the possibility of a demyelinating disorder. However, spinal cord and brain MRI revealed hemosiderin deposition along the entire neuraxis. A rigorous electrophysiologic study confirmed a functional impairment in many different levels of the nervous system. CONCLUSION: The demonstration of CSF oligoclonal bands in the reported patient implies that inflammation might be involved in the pathogenesis of superficial siderosis. The diagnosis of this newly recognizable entity needs a high clinical suspicion, but further research is needed to fully elucidate the involved mechanisms.

Sudomotor dysfunction is associated with foot ulceration in diabetes.

AIM: To examine the relationship between sudomotor dysfunction and foot ulceration (FU) in patients with diabetes. METHODS: Ninety patients with either Type 1 or Type 2 diabetes [30 without peripheral sensorimotor neuropathy (PN), 30 with PN but without FU and 30 with FU] were recruited in this cross-sectional study. Assessment of PN was based on neuropathy symptom score (NSS), neuropathy disability score (NDS) and vibration perception threshold (VPT). Sudomotor dysfunction was assessed using the sympathetic skin response (SSR). Cardiac autonomic nervous system activity was assessed by the battery of the classical autonomic function tests. RESULTS: Patients with foot ulcers had longer duration of diabetes, higher values of VPT and NDS and lower values of the autonomic functions tests in comparison with the other study groups. Sudomotor dysfunction and cardiac autonomic neuropathy were significantly more common in the FU group. Multivariate logistic regression analysis after adjustment for gender, body mass index, duration of diabetes and glycated haemoglobin (HbA(1c)) demonstrated that the odds ratio (95% confidence intervals) of FU increased with measures of neuropathy such as NDS >or= 6 (10.2, 6.2-17.3) and VPT >or= 25 volts (19.8, 9.9-47.5), but was also significantly increased with absent SSR (15.3, 5.3-38.4). CONCLUSIONS: Sudomotor dysfunction is associated with increased risk of FU and should be included in the screening tests for identification of diabetic patients at risk of ulceration.

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.

Spastic paretic hemifacial contracture in multiple sclerosis: a neglected clinical and EMG entity.

BACKGROUND: Spastic paretic hemifacial contracture (SPHC) is an uncommon condition, originally described as a sign of brainstem neoplasia, characterized by sustained unilateral contraction of the facial muscles associated with mild ipsilateral facial paresis. SPHC has only rarely been reported in the context of multiple sclerosis (MS). To further study and assess the frequency of SPHC in patients with MS. METHODS: We screened clinically 500 consecutive patients with MS for the presence of SPHC and further studied electrophysiologically any cases identified. RESULTS: We identified two patients who developed the condition during the course of an MS relapse. The estimated frequency of the condition was 0.4%. Both patients had relapsing-remitting MS. SPHC was characterized on Electromyography (EMG) by continuous resting activity of irregularly firing motor unit potentials, associated with impaired recruitment of motor units on voluntary contraction. Myokymic discharges were not present. Blink reflex studies were partly consistent with midpontine lesions in the vicinity of the facial nucleus ipsilateral to SPHC. MRI showed lesions in the ipsilateral dorsolateral midpontine tegmentum. CONCLUSIONS: SPHC constitutes a rare but distinct clinical and EMG entity in patients with MS.

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.

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.

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.

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.

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.

Cognition in epilepsy: a multichannel event related potential (P300) study.

Auditory event-related potentials (AERP) were elicited in 68 epileptic patients and 30 age-matched controls. Epileptic patients had significantly prolonged N2 and P300 (P3) latencies compared with controls. Seven patients were above the range of 3 standard deviations from the control mean values. Amongst epileptics, patients with temporal lobe epilepsy had significantly prolonged P3 latencies compared to patients with idiopathic generalized epilepsy. Patients with abnormal EEGs had significantly prolonged P3 latencies compared to those with normal EEGs. Patients on anticonvulsant monotherapy had shorter P3 latencies, compared to patients taking a combination of two or more anticonvulsants. Patients on shorter duration of treatment had less prolonged P3 latencies compared to those on longer anticonvulsant treatment.