Motor unit territories in juvenile myoclonic epilepsy patients.

In this study, the scanning EMG technique was implemented to investigate electrophysiological cross-sections of the motor unit (MU) territories in healthy volunteers and in subjects with juvenile myoclonic epilepsy and spinal muscular atrophy. Measurements were taken intramuscularly by means of two concentric needle electrodes from biceps brachialis muscles. 3-D maps of the MU territories were plotted for each MU to determine the lengths of MU cross-section and the maximum amplitudes of each MU. There was evidence of a preponderance of large MUs in patients with juvenile myoclonic epilepsy.

A comparative ID migraine screener study in ophthalmology, ENT and neurology out-patient clinics.

Migraine is more likely to be misdiagnosed in patients with comorbid diseases. Not only primary care physicians, but also specialists might misdiagnose it due to the lack of diagnostic criteria awareness. The ID migraine test is a reliable screening instrument that may facilitate and accelerate migraine recognition. This study aimed to compare the prevalence and characteristics of migraine in a large sample of patients admitted to clinics of ophthalmology (OC), ear, nose and throat diseases (ENTC) and neurology (NC), as well as to validate the use of the ID migraine test in OC and ENTC settings. This was a multicentre (11 cites) study of out-patients admitting either to NC, ENTC or OC of the study sites during five consecutive working days within 1 week. From each of the clinics, 100 patients were planned to be recruited. All recruited patients were interviewed and those having a headache complaint received an ID migraine test and were examined for headache diagnosis by a neurologist, blinded to the ID migraine test result. A total of 2625 subjects were recruited. Only 1.3% of OC patients and 5.4% of ENTC patients have been admitted with a primary complaint of headache, whereas the percentage of NC patients suffering from headache was 37.6%. Whereas 138 patients (19.3%) in OC, 154 (17.3%) in ENTC and 347 (34%) in NC were found to be ID migraine test positive, 149 patients (20.8%) in OC, 142 (16%) in ENTC and 338 (33.1%) in NC were diagnosed with migraine. The sensitivity, specificity, and positive and negative predictive ratios of the ID migraine test were found to be similar in all clinics. An important fraction of the patients admitted to NC, as well as to OC and ENTC, for headache and/or other complaints were found out to have migraine by means of a simple screening test. This study validated the ID migraine test as a sensitive and specific tool in OC and ENTC, encouraging its use as a screening instrument.

Validity of the ID-Migraine screener in the workplace.

OBJECTIVE: The impact of migraine on physical, social, and emotional performance is considerable, yet it remains an underdiagnosed disorder. ID-Migraine is a validated migraine-screening tool developed to facilitate diagnosis. This study evaluated the validity and use of the Turkish version of the ID-Migraine screener (ID-Ms) in the workplace, and measured the impact of headache on disability, productivity, and quality of life among the workforce. METHODS: A total of 465 employees from four companies were interviewed for screening with the ID-Ms. Subjects were included in the study if they reported two or more headaches in the past 3 months and gave a positive answer to one of the two ID-Ms prescreening questions. Eligible subjects completed the ID-Ms, the Migraine Disability Assessment Questionnaire, and the Medical Outcomes Study 36-Item Short Form Health Survey. Subjects were then evaluated for confirmation of their diagnosis according to the International Classification of Headache Disorders, 2nd edition (ICHD-2) criteria. RESULTS: A total of 227 subjects (mean age 31.9 +/- 5.9 years; 65.6% women) completed the study. Migraine was diagnosed in 106 of the 227 subjects (46.7%) according to the ID-Ms and in 117 of the 227 subjects (51.5%) according to ICHD-2 criteria. The sensitivity of the ID-Ms was 70.9%, specificity was 79.1% and Cohen kappa value was 0.50. Workdays lost over the previous 3 months due to headache amounted to 8.7 +/- 9.5 days for migraine-positive and 4.9 +/- 6.6 days for migraine-negative subjects. CONCLUSION: The Turkish version of the ID-Migraine screener is a valid tool for identifying subjects with migraine in the workplace.

Evaluation and proposal for optimalization of neurophysiological tests in migraine: part 1--electrophysiological tests.

Neurophysiological testing has become a valuable tool for investigating brain excitability and nociceptive systems in headache disorders. Previous reviews have suggested that most neurophysiological tests have limited value for headache diagnosis, but a vast potential for exploring the pathophysiology of headaches, the central effects of certain pharmacological treatments and phenotype-genotype correlations. Many protocols, however, lack standardization. This meta-analytical review of neurophysiological methods in migraine was initiated by a task force within the EUROHEAD project (EU Strep LSHM-CT-2004-5044837-Workpackage 9). Most of the neurophysiological approaches that have been used in headache patients are reviewed, i.e. evoked potentials, nociception-specific blink reflex, single-fibre electromyography, neuroimaging methods (functional MRI, PET, and voxel-based morphometry) and the nitroglycerin attack-provoking test. For each of them, we summarize the results, analyse the methodological limitations and propose recommendations for improved methodology and standardization of research protocols. The first part is devoted to electrophysiological methods, the second to neuroimaging techniques and the NTG test.

Investigation of neuromuscular transmission in some rare types of migraine.

The aim of this study was to delineate any dysfunction of neuromuscular transmission (NMT) by single-fibre electromyography (SFEMG) in some rare types of migraine. Recent studies have shown subclinical dysfunction of NMT in migraine with aura and cluster headache by using SFEMG, whereas another recent study has shown NMT to be normal in familial hemiplegic migraine (FHM) with CACNA1A mutations. Thirty patients with rare primary headache syndromes [18 with sporadic hemiplegic migraine (SHM), six with FHM and six with basilar-type migraine (BM)] and 15 healthy control subjects without any headache complaints underwent nerve conduction studies, EMG and SFEMG during voluntary contraction of the extensor digitorum communis muscle. Ten to 20 different potential pairs were recorded and individual jitter values calculated. The results obtained from patient groups were compared with those from the normal subjects. Of 600 individual jitter values of the patients, 27 (4.5%) were abnormally high, whereas only 3/205 (1.5%) jitter values from normal subjects were abnormal. Abnormal NMT was found in 4/30 (13.3%) patients (three SHM and one BM), but in none of the control subjects. Only in SHM patients was the number of individual abnormal jitter values slightly but significantly different from normal controls. The present study demonstrates that subclinical NMT abnormality is slightly present in only SHM and BM patients, but not in FHM patients.

Subclinical neuromuscular transmission abnormality detected by single-fibre EMG is more pronounced in cluster headache than in migraine with aura.

The aim was to investigate neuromuscular transmission (NMT) by single-fibre EMG (SFEMG) in a large series of patients having migraine with aura (MA) or cluster headache (CH). Recent studies using SFEMG have shown subclinical dysfunction of NMT in MA and CH. Forty-three patients having MA, 51 with CH and 38 healthy control subjects underwent nerve conduction studies, EMG and SFEMG during voluntary contraction of the extensor digitorum communis muscle. Twenty different potential pairs were recorded and individual, mean and total abnormal individual jitter values were calculated. The results obtained from MA patients were compared with those from CH patients. In MA patients, 32 of 860 jitters were abnormally high, whereas 73 of 1020 of the jitters showed this abnormality in CH patients. None of the control subjects, five MA patients (11.6%) and 11 CH patients (21.6%) were designated as having subclinical NMT abnormality. Thus, patients having junction dysfunction were significantly more common in the CH group. The subclinical NMT abnormality shown by SFEMG is more common in CH than in MA. These two primary headache syndromes may have some shared functional abnormality of NMT constituents which is more evident in CH.

Humoral immune response against 38-kDa and 16-kDa mycobacterial antigens in tuberculosis.

Several ELISA tests based on mycobacterial antigens have been used for the rapid diagnosis of tuberculosis (TB), although demonstration of Mycobacterium tuberculosis in a smear or culture is the most reliable method. In the present study, the diagnostic value of 16-kDa and 38-kDa mycobacterial antigens was investigated in patients who were diagnosed with tuberculosis by clinical and/or bacteriological findings in Turkey. The PATHOZYME-TB Complex Plus commercial ELISA kit was used for measuring immunoglobulin G against 38-kDa and 16-kDa recombinant antigens. Humoral immune response was analysed in a group of 179 TB patients (143 smear-positive, 19 smear-negative, eight lymphadenitis and nine pleuritis), 15 inactive TB cases and in control groups consisting of 40 healthy volunteers and 20 subjects with pulmonary diseases other than TB. The sensitivity, specifity, positive predictive value and negative predictive value of the test were determined at 52.5%, 93.3%, 95.9% and 39.7%, respectively in TB cases. Antibodies were detected at above cut-off level in three (20%) out of 15 subjects with inactive TB. In conclusion, the ELISA test has a very good specifity and an acceptable sensitivity and positive predictive value. It is thought that it could be used in combination with other methods to increase diagnostic accuracy, especially for culture-negative tuberculosis cases, which are difficult to diagnose.

Evaluation of neuromuscular transmission by using monopolar needle electrode.

OBJECTIVE: To evaluate the value of single-fibre electromyography (SFEMG) with monopolar electrode (MNPE) in revealing neuromuscular transmission dysfunction. MATERIAL AND METHODS: We examined the extensor digitorum communis muscle by using single-fibre electrode (SFE) and MNPE sequentially, in randomly assigned 20 healthy volunteers and in 17 patients with known myasthenia gravis (MG). The high-pass filter setting was 3 kHz for MNPE. Ten individual jitter values were calculated for each electrode in every muscle. Repetitive nerve stimulation (RNS) test on trapezius muscle was performed on 15 patients. RESULTS: In controls, the mean jitter values were 27 +/- 9 (10-59) micro s with SFE, and 21 +/- 7.2 (9-56) micro s with MNPE (P = 0.001). In the MG group, the mean jitter values were 52.4 +/- 38 (12-221) micro s with SFE, and 51.8 +/- 34.7 (12-179) micro s with MNPE. Both electrodes identified junction dysfunction in 14 patients. RNS revealed decrement in four patients but 11. CONCLUSION: SFEMG with SFE is still the gold standard; however, SFEMG with MNPE is superior to RNS like SFEMG with SFE.

Headache in Behçet's disease.

The aim of this study was to investigate the characteristics of headache in patients with Behçet's disease (BD) seeking neurological consultation. Consecutive patients with BD seen within 1 year at the neuro-Behçet's out-patient clinic were studied using an electronic database according to the classification criteria of the International Headache Society. During a 12-month period 118 BD patients were admitted, and 98 had headaches. Migraine was the most common type of primary headache diagnosed in 45 patients (46.4%) in the whole headache group, followed by tension-type headache (TTH) in 26 cases (26.8%). Thirty-seven patients had secondary headaches mainly due to cerebral venous thrombosis or parenchymal neurological involvement of BD. Of these patients, 15 had both primary and secondary headaches. The primary headaches of 13 patients were exacerbated with systemic BD flare-ups, and four patients had migraine attacks triggered only by systemic BD activation which showed a good response to the treatment of systemic inflammation. The majority of the headaches of patients with BD do not indicate any neurological involvement; they are usually due to migraine or TTH. In a minority of patients, migraine associated with systemic inflammation of BD is notable.

Optimum trace count necessary for jitter calculation in single-fiber electromyography.

OBJECTIVE: To clarify the optimum trace count for jitter calculation. MATERIALS AND METHODS: Single-fiber electromyography was performed during voluntary contraction (VC-SFEMG) of extensor digitorum muscle in six healthy and five myasthenic subjects. Twenty single-fiber action potential (SFAP) pairs were recorded from each subject. For each pair, 100 consecutive traces were recorded and stored for off-line analysis. Ten different jitters were calculated in 10 consecutive steps for each SFAP pair by increasing the number of traces included to analysis (from 10 to 100). The jitter calculated in each step was compared with that calculated from 100 traces. RESULTS: Sixty was the optimum number of trace count for both myasthenics and normal controls. Using less than 60 traces for jitter calculation revealed lower values. CONCLUSION: Jitter calculation should be performed from at least 60 traces in VC-SFEMG. Less numbers yield lower jitter and may cause diagnostic error.

Disposable concentric needle electromyography electrodes artifact discharge mimicking positive sharp waves.

OBJECTIVES: To determine a new artifact discharge produced from the disposable concentric needle (DCN) electromyography (EMG) electrodes. METHODS: We have recorded the activity obtained after the first insertion of 41 DCN (37 mm) and 36 DCN (50 mm) in several muscles during the rest. The number of the patients was 77 (26 males, 51 female). RESULTS: We observed an artifact discharge (AD) resembling positive sharp waves (PSWs) in 31 patients of 77 insertions. The AD occurred with 18 of 41 insertions of DCN 37 mm and 13 of DCN 50 mm. The artifact resolved when the needle has been moved in the muscle or in the adipose subcutaneous tissue. CONCLUSION: This AD should be recognized when using DCN electrodes to avoid confusion with PSWs. Recognizing these artifacts during needle EMG is important to avoid false positive results.

Stiff leg syndrome: case report.

We report on a 28-year-old woman with insulin-resistant diabetes mellitus with a 5-year history of progressive stiffness and painful spasms of the right leg, exaggerated by sudden auditory and tactile stimuli or by emotional stress. There were no signs of truncal rigidity or exaggerated lumbar lordosis. Anti-glutamic acid decarboxylase antibodies were positive in her serum. She improved substantially with clonazepam 4 mg/day. She presented with electrophysiological findings not previously reported in stiff leg syndrome, which may suggest increased inhibition in the uninvolved upper extremities.

F wave parameters and F tacheodispersion in mild diabetic neuropathy.

F tacheodispersion and some F wave parameters have previously been suggested to be useful in the detection of peripheral nerve involvement in diabetic patients with normal nerve conduction studies. In this study, ulnar and tibial F wave parameters of diabetic cases with normal motor and sensory nerve conduction studies (Group 1) were calculated, F tacheodispersion histograms were constructed and compared with the same parameters obtained from the normal controls (Control group) and diabetic cases with abnormal motor and sensory nerve conduction examinations (Group 2). There was a tendency towards lower conduction velocities in ulnar and tibial tacheodispersion histograms of Group 1 and Group 2, as compared to Control group. Most of the F wave values were significantly abnormal in Group 2 in comparison to other two groups, whereas statistically significant differences between Group 1 cases and Control group were found in minimum ulnar F wave conduction velocity (FCVmin), mean ulnar FCV (FCVmean), tibial FCVmin and tibial FCVmean values. Unlike other methods, F waves give information about the entire length of the motor nerve fiber. In mild neuropathies, in which nerve fibers are damaged uniformly, testing the whole length of a nerve with this method may be beneficial in detection of a mild conduction abnormality.

Analysis of gastrocnemius compound muscle action potential in rat after death: significance for the estimation of early postmortem interval.

The estimation of postmortem interval is of great importance in forensic medicine. Changes in the properties of excitable tissue provide another possible means by which the time of death can be estimated. This paper reports the monitorization of the compound action potentials recorded from gastrocnemius muscle by means of sciatic nerve stimulation in rats before and after death. The sciatic nerve was stimulated using rectangular impulses of 0.1ms duration and intensities ranged between 1 and 100mA while the rat was alive. Subsequently, the rat was killed by cervical dislocation. The similar measurement procedure was performed at the moment of death and every 5min after sequentially. There was a progressive decline in amplitude values that began 10min after death. The decrease in the amplitude of the compound muscle action potentials (CMAP) was most prominent especially when elicited with lower stimulus intensities. The mean area of the CMAPs also began to decrease beginning from 15min after death. Fifteen minutes after death, the motor latencies began to prolong. Thirty-five minutes after death, the decline in amplitude and area of mean CMAP was most prominent as the mean motor latency. At the 40th minute, most of the CMAPs were unelicitable. During the early postmortem interval, these amplitude, area and motor latency alterations decrease in the amplitude and area, prolongation of motor latency seems to be well correlated with each other and this was statistically significant. These findings are discussed as possible basis of a forensic method for postmortem interval estimation.

Concentric needle electrode for neuromuscular jitter analysis.

We used a concentric needle electrode (CNE) with 2 kHZ low-cut filter and a single fiber electrode (SFE) in the same subjects for neuromuscular jitter measurement in the extensor digitorum communis (EDC) and orbicularis oculi (OOc) muscles. At the same session, 20 jitter values were obtained from each subject with each electrode. For EDC (during voluntary contraction), mean jitter values with SFE and CNE were 23.4 +/- 8 micros and 23.3 +/- 8 micros in 10 normals; and 56.8 +/- 28 micros and 57.4 +/- 33 micros in 10 myasthenics. For OOc (during electrical stimulation), mean jitter values with SFE and CNE were 17.9 +/- 5 micros and 16.3 +/- 4 micros in 11 normal subjects, and 41.2 +/- 29 micros and 36.7 +/- 27 micros in 10 myasthenics. For both muscles, the numbers of individual abnormal jitter values with SFE and CNE were highly comparable. Both needles labeled the same patients as having "normal" or "abnormal" neuromuscular transmission. CNE may be an alternative to SFE in neuromuscular jitter analysis.

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

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

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

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

Surface stimulation single-fiber electromyography.

Stimulation single-fiber electromyography (S-SFEMG) is an alternative method to SFEMG during voluntary contraction (VC-SFEMG). S-SFEMG is preferred to VC-SFEMG in uncooperating patients, children, and patients having severe weakness. Surface stimulation is a viable alternative to needle stimulation in S-SFEMG. In the present study, surface versus needle stimulation of facial nerve has been tested by recording from the orbicularis oculi and frontalis muscles. Jitter values obtained by both methods have been found to be nearly equal.

Effects of bolus volume on oropharyngeal swallowing: an electrophysiologic study in man.

OBJECTIVE: Different variables of oropharyngeal swallowing change in response to bolus volume and consistency as determined by manometric/videofluoroscopic studies. But the subject is debatable especially from the physiologic point of view. No electrophysiologic studies are available on human subjects. METHODS: The effects of bolus volume and viscosity on different variables of oropharyngeal swallowing were investigated using electrophysiologic methods. Mechanical upward and downward laryngeal movements and submental electromyographic (SM-EMG) activity of the laryngeal elevator muscles were recorded during dry and 3-, 10-, and 20-ml water swallowing in 14 normal subjects. Cricopharyngeus (CP) muscle was investigated during 3- and 10-ml water swallowing in 10 normal subjects. Semisolid and liquid swallowing were compared in eight normal subjects. RESULTS: The total duration of SM-EMG, time necessary for larynx elevation, CP-EMG pause related with upper esophageal sphincter opening and swallowing variability (jitter) all increased significantly with increasing bolus volume. Laryngeal superior relocation time and CP-EMG pause were shorter for semisolid swallowing compared with swallowing the same amount of liquid. CONCLUSION: The duration of SM-EMG activity, laryngeal upward-downward movements, and CP-EMG pause are affected by sensory inputs such as volume and viscosity of the bolus swallowed. The results indicate that sensory input modifies the central swallowing pattern although basic events remain the same in normal human subjects.

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

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