Electrodiagnostic methods to verify Guillain-Barré syndrome subtypes in Istanbul: A prospective multicenter study.

BACKGROUND AND AIMS: This study aimed to identify the clinical characteristics and electrodiagnostic subtypes of Guillain-Barré syndrome (GBS) in Istanbul. METHODS: Patients with GBS were prospectively recruited between April 2019 and March 2022 and two electrodiagnostic examinations were performed on each patient. The criteria of Ho et al., Hadden et al., Rajabally et al., and Uncini et al. were compared for the differentiation of demyelinating and axonal subtypes, and their relations with anti-ganglioside antibodies were analyzed. RESULTS: One hundred seventy-seven patients were included, 69 before the coronavirus disease 2019 pandemic (April 2019-February 2020) and 108 during the pandemic (March 2020-March 2022), without substantial changes in monthly frequencies. As compared with the criteria of Uncini et al., demyelinating GBS subtype diagnosis was more frequent according to the Ho et al. and Hadden et al. criteria (95/162, 58.6% vs. 110/174, 63.2% and 121/174, 69.5%, respectively), and less frequent according to Rajabally et al.'s criteria (76/174, 43.7%). Fourteen patients' diagnoses made using Rajabally et al.'s criteria were shifted to the other subtype with the second electrodiagnostic examination. Of the 106 analyzed patients, 22 had immunoglobulin G anti-ganglioside antibodies (14 with the axonal subtype). They had less frequent sensory symptoms (54.5% vs. 83.1%, p = 0.009), a more frequent history of previous gastroenteritis (54.5% vs. 22.9%, p = 0.007), and a more severe disease as compared with those without antibodies. INTERPRETATION: Serial electrodiagnostic examinations are more helpful for accurate subtype diagnosis of GBS because of the dynamic pathophysiology of the disease. We observed no significant increase in GBS frequency during the pandemic in this metropolis.

Automatic detection of F waves and F-MUNE in two types of motor neuron diseases.

INTRODUCTION/AIMS: Motor unit number estimation by F waves (F-MUNE) is an uncommonly used MUNE technique. Our aim in this study was to assess the sensitivity of F-MUNE values elicited with newly developed software in motor neuron diseases. METHODS: F waves were recorded by 300 submaximal stimuli from abductor digiti minimi and abductor pollicis brevis muscles of 35 patients with amyotrophic lateral sclerosis, 18 with previous poliomyelitis, and 20 controls. The software determined the surface motor unit action potentials (sMUAPs) and calculated the F-MUNE values. Compound muscle action potential scans were also recorded to obtain MScanFit. RESULTS: The sMUAP amplitudes were higher and F-MUNE values were lower in both muscles of the patients when compared with controls. F-MUNE values could distinguish patients from controls. Significant correlations were found between F-MUNE and MScanFit in the patient groups. DISCUSSION: The new F-MUNE software offered promising results in revealing motor unit loss caused by motor neuron diseases.

Compound muscle action potential scan and MScanFit motor unit number estimation during Wallerian degeneration after nerve transections.

BACKGROUND: Compound muscle action potential (CMAP) scan and MScanFit have been used to understand the consequences of denervation and reinnervation. This study aimed to monitor these parameters during Wallerian degeneration (WD) after acute nerve transections (ANT). METHODS: Beginning after urgent surgery, CMAP scans were recorded at 1-2 day intervals in 12 patients with ANT of the ulnar or median nerves, by stimulating the distal stump (DS). Stimulus intensities (SI), steps, returners, and MScanFit were calculated. Studies were grouped according to the examination time after ANT. Results were compared with those of 27 controls. RESULTS: CMAP amplitudes and MScanFit progressively declined, revealing a positive correlation with one another. SIs were higher in WD groups than controls. Steps appeared or disappeared in follow-up scans. The late WD group had higher returner% than the early WD and control groups. CONCLUSIONS: MScanFit can monitor neuromuscular dysfunction during WD. SIs revealed excitability changes in DS.

Prospective Analysis of the Swallowing Reflex After Sagittal Split Osteotomy: Comparison with Normal Volunteers.

The aim of this study was electromyographic description of changes in swallowing before and after bilateral sagittal split ramus osteotomy. In this prospective study, twenty-eight patients were divided into 3 groups according to the occlusion pattern: Group I (Angle Class III), Group II (Angle Class II), and Control (Class I). Serial cone-beam computed tomography analyses and electromyographic data were collected preoperatively, 1st and 6th months after setback surgery in Group I, and advancement surgery in Group II. Swallowing reflex with 3-20 ml water bolus were studied. Patients were further divided into two subgroups according to the magnitude of relapse. The mean setback of the mandible was 4.62 ± 1.92 mm in Group I, and the mean advancement was 4.19 ± 2.00 mm in Group II. Mandibular relapse rate was 17.40%. Oral preparation phase shortened after surgery in both study groups. Two subjects in Group II and one in Group I had piecemeal deglutition, and two of them became normal postoperatively. Most of the swallowing durations of the relapsed cases were longer than those of stabilized patients. Important clinical considerations are as follows: the oral preparation period becomes shorter after surgery; piecemeal deglutition may disappear after treatment; and individuals with a longer oral period and piecemeal deglutition may have increased tendency to skeletal relapse. This multidisciplinary study enhances our understanding of the adaptive response to the swallowing reflex after orthognathic surgery and provides novel insight into the association between the submental muscle activity and relapse in orthognathic patients.

Dropping Objects in Carpal Tunnel Syndrome: Clinical and Electrophysiological Features.

Background Dysfunction in both afferent sensory and efferent motor components of the median nerve may contribute to the manifestation of the symptom of dropping objects (DO) in carpal tunnel syndrome (CTS). The objective of this study was to compare the clinical and electrophysiological characteristics of CTS patients with dropping objects (wDO) and those without dropping objects (w/oDO). The study evaluated the correlation between DO symptoms and median partial conduction block, as well as the reduction in median motor conduction velocity at the wrist. Methodology An examination for CTS and the Boston Carpal Tunnel Syndrome Questionnaire (BCTQ) were performed. Median and ulnar sensory and motor nerve conduction studies were conducted in both upper extremities, and the percentage decrease in the median compound motor action potential amplitude at the wrist level was calculated. Results The study included 201 female participants aged between 22 and 88 years, comprising 57 patients with CTSwDO, 78 patients with CTSw/oDO, and 66 healthy controls. In the CTSwDO group, compared to the CTSw/oDO group, BCTQ scores were significantly higher, the prevalence of sensory deficits was more pronounced, and a larger number of hands, both dominant and non-dominant, were classified as stage 3 or higher in the clinical CTS classification. However, no correlation was found between the presence of DO symptoms and any neurophysiological findings. Conclusions DO may be a symptom of clinical severity in CTS, as previously reported. No neurophysiological parameter that could be associated with DO was identified.

Differentiation of Post-Polio Syndrome from Prior Poliomyelitis Sequela by Assessing Paraspinal Muscle Involvement in Magnetic Resonance Imaging.

Background/Objectives: Post-polio syndrome (PPS) affects former polio patients, manifesting decades after initial infection with progressive symptoms like pain, fatigue, and muscle weakness. Diagnosis relies on the clinical criteria and exclusion of other probable causes. The purpose of this study is to determine the scope and new diagnostic value of magnetic resonance imaging (MRI) in identifying muscle involvement in PPS and distinguishing it from prior poliomyelitis (PPM). Methods: This study was approved by the Koç University Ethics Committee with Approval No. 2023.409.IRB2.090. Electronic medical archives from two academic institutions were searched for records tagged with ICD code B-91 for poliomyelitis sequalae. The resulting search query of 291 records was manually sorted for PPS and PPM, medical history, clinical examination findings, and lumbar MR images down to 32 patients. Two independent radiologists evaluated the paraspinal musculature in the MRIs using the Mercuri scale. Inter-rater agreement, comparison of the paraspinal musculatures between groups, and their relationship to leg involvement were assessed with the resulting data. Results: Inter-rater agreement was found to be almost perfect across all muscles, except for the multifidus muscle. When clinical examination findings were included for these muscles, quadratus lumborum (QL) degradation was found in both right-side (p = 0.017) and left-side (p = 0.002) leg involvement. Conclusions: QL muscle deterioration may serve as a diagnostic marker for PPS, potentially guiding lumbar pain treatment through rehabilitation.

Prevalence of Carpal Tunnel Syndrome Symptoms Among Young Dentists.

Objectives Although age is a risk factor, carpal tunnel syndrome (CTS) can also affect younger individuals, particularly those involved in activities or occupations that require repetitive hand movements, forceful gripping, or prolonged wrist flexion/extension. This case-control study aimed to examine the prevalence of CTS symptoms and frequent object dropping among a group of young dentists who are exposed to CTS risk factors. Additionally, other reported risk factors for CTS, such as sex, obesity, and square wrist sign, were also investigated. Methods A total of 74 dentists (48 women, mean age 28.5 years), who are working at Istanbul Faculty of Dentistry, the largest dental school in Istanbul, which is the biggest city in Turkey, were included in the study. Additionally, 61 age- and sex-matched controls (38 women, mean age 27.9 years) were also recruited. The Edinburgh Hand Preference Questionnaire, Boston Carpal Tunnel Syndrome Questionnaire (BCTQ), a questionnaire for object dropping and occupational hand usage, anthropometric measurements of the hands, clinical neurologic examination, and electromyography intended for the detection of CTS were performed. Results The dentists had a higher total weekly hand usage duration compared to the controls (66.3 vs 44.8 hours, p<0.001). BCTQ scores and the frequency of object dropping were also significantly higher in dentists compared to controls (respective p values: 0.011, 0.003). Positive correlations were found between BCTQ scores, hand usage durations, and object dropping (respective p values: 0.001, <0.001). BCTQ scores were higher in women than in men (p=0.027). Electrophysiologic evidence of CTS was found in one dentist. Conclusions Symptoms of CTS may manifest in individuals at a younger age than predicted, primarily influenced by their occupation and the duration of hand usage. Dentists, in particular, report a higher incidence of complaints related to object dropping, which can be attributed to their frequent use of specialized tools and engagement in delicate tasks, resulting in heightened awareness. However, it can also potentially serve as an indicator of CTS.

Effects of sagittal split osteotomy on brainstem reflexes.

OBJECTIVES: This prospective study was designed to assess whether patients with skeletal deformities show characteristic masseter inhibitory reflex (MIR) and blink reflex (BR) patterns. A secondary aim was to investigate whether these reflexes change following bilateral sagittal split osteotomy (BSSO). MATERIALS AND METHODS: Fourteen consecutive patients who underwent single-jaw BSSO and 14 class I subjects who constituted the control group were enrolled into the study. MIR and BR, obtained by the stimulation of supraorbital (SBR) and mental nerves (MBR), were electrophysiologically recorded. Sensory impairment in the mental nerve distribution was clinically tested. Three evaluation periods were specified as immediately before (T0), 1 month (T1) and 6 months (T2) after surgery. RESULTS: MIR early silent period duration was significantly shorter in the patients at T0 (p < 0.001). Sensory deficits developed on 23 sides after BSSO, of which, 17 recovered after 6 months. At T1, MBR was inelicitable bilaterally in 3 patients and unilaterally in 2 patients. These responses were still unrecordable bilaterally in 1 patient, and unilaterally in 4 patients at T2. MIR were unrecordable on 18 sides at T1 and recovered on 11 sides at T2. There were no parallels between the clinical sensory deficits and the abnormal results of the reflexes. CONCLUSIONS: Shorter MIR in patients with dentofacial abnormalities may be a reflection of an adapted trigeminal reflex mechanism. Although MBR and MIR abnormalities do not develop parallel to the clinical sensory deficits, their course might provide insights into the disturbed trigeminal reflex pathways.

Continuous theta-burst stimulation in patients with drug-resistant epilepsy: A single-blind placebo-controlled cross-over pilot study.

OBJECTIVES: To evaluate the effect of continuous theta-burst stimulation (cTBS) in patients with drug-resistant epilepsy (DRE). METHODS: Twelve patients with DRE (five with idiopathic generalized and seven with focal epilepsy) were included in this cross-over design study and randomized to either first sham or first active stimulation, each applied for 5 consecutive days. A round coil over the vertex was used in generalized epilepsy or a figure-of-8 coil over the "epileptogenic area" in focal epilepsy. Sham stimulation was given by placing the coil 90° perpendicular to the head. The number of seizures, electroencephalography findings, Quality of Life in Epilepsy Inventory (QOLIE-84), and Symptom Check List (SCL-90) scores evaluated during the 8-12 weeks before and after active and sham stimulations were compared statistically. RESULTS: Eight patients could complete both active and sham stimulation periods of 5 days and two patients completed active stimulation sessions, without any significant adverse effects. The number of seizures significantly reduced after active cTBS, but not after sham stimulation, when compared with those recorded before the stimulation period. QOLIE scores were increased, but interictal epileptiform discharges and SCL-90 scores showed no difference after cTBS. Active stimulation was stopped in one patient after he experienced an aggravation of myoclonic seizures. CONCLUSIONS: cTBS seemed to be relatively safe and gave promising results in reducing the frequency of seizures in patients with both generalized and focal DRE. This time-saving technique may ease the introduction of repetitive transcranial magnetic stimulation into the routine practice of busy epilepsy clinics.

Cutaneous allodynia and thermal thresholds in chronic migraine: The effect of onabotulinumtoxinA.

OBJECTIVE: Cutaneous allodynia (CA) is a common symptom in migraine. Its incidence is more frequent in the chronic migraine (CM). CA usually occurs during pain attacks. However, it can also be interictal and its frequency and severity seem to be correlated with the duration of the disease. Several quantitative sensory testing (QST) studies have revealed variable results about mechanical and thermal allodynia accompanying migraine. This study aimed to investigate the effects of CA and onabotulinumtoxinA (BoNT-A) injection on the thermal thresholds measured by QST in patients with CM. The effects of BoNT-A on headaches, CA, and other accompanying symptoms of migraine were also evaluated. METHODS: Single BoNT-A injections were performed in 22 female cases (mean age: 38.1 ± 7.2 years) with CM. Patients were evaluated at 1-7 days before, 28-35, and 84-91 days after the injection. The 22 healthy women in the control group (mean age: 36.6 ± 7.6 years) were examined once. Headache and its characteristics, medication intake, allodynia, presence of anxiety, and depression symptoms were evaluated through relevant scales. The heat (HDT) and cold (CDT) detection thresholds on the forehead and hand were measured bilaterally with QST. The presence of brush allodynia for patients was examined by applying a 4 × 4 gauze pad over the same areas. RESULTS: The patients in the CM group had migraine for an average of 22.5 ± 6.1 years and CM for 6.1 ± 3.2 years. The average number of painful days per month was 22.1 ± 4.0 days. All the patients had migraine attacks with CA (mean 5.6/month). The average allodynia symptom checklist (ASC-12) score was 7.8 ± 6.2. Thermal thresholds measured in the patients with CM were similar to those of the controls. Thermal thresholds did not show significant differences between the symptomatic and the asymptomatic sides at the last migraine attack. There was also no correlation between the allodynia revealed by the physical examination and the thermal thresholds detected by QST. The ASC-12 score decreased significantly with BoNT-A injection (p = 0.030), but no significant change was observed in thermal thresholds after this treatment. CONCLUSION: There was no significant correlation between CA and thermal thresholds. BoNT-A was successful in relieving headache and other associated symptoms, including CA, but had no significant effect on QST parameters.

Corticomotor Excitability in Two Kinds of Motor Neuron Diseases: A Study on the Patients With Amyotrophic Lateral Sclerosis and Poliomyelitis Survivors.

PURPOSE: To examine upper motor neuron functions comparatively in patients with amyotrophic lateral sclerosis (ALS) and poliomyelitis survivors using transcranial magnetic stimulation (TMS) methods. METHODS: Single- and paired-pulse TMS with conventional methods and the triple-stimulation technique were performed by recording from the abductor digiti minimi and abductor pollicis brevis muscles in 31 patients with ALS, 18 patients with poliomyelitis survivors, and 21 controls. Nine patients were diagnosed as having postpoliomyelitis syndrome after a 6-month follow-up. RESULTS: Triple-stimulation technique and some of conventional TMS studies were able to distinguish ALS from both poliomyelitis survivors and controls. A reduced ipsilateral silent period in abductor pollicis brevis muscles was the only parameter to show a significant difference when comparing thenar and hypothenar muscles in ALS. No significant difference was present in any TMS parameters between the postpoliomyelitis syndrome and non-postpoliomyelitis syndrome groups. CONCLUSIONS: Conventional TMS and particularly triple-stimulation technique studies are helpful in disclosing upper motor neuron dysfunction in ALS. The results of this study might favor the cortical hypothesis for split hand in ALS, but they revealed no significant indication for upper motor neuron dysfunction in postpoliomyelitis syndrome.

Repeater F-waves in amyotrophic lateral sclerosis: Electrophysiologic indicators of upper or lower motor neuron involvement?

OBJECTIVE: To extract insight about the mechanism of repeater F-waves (Frep) by exploring their correlation with electrophysiologic markers of upper and lower motor neuron dysfunction in amyotrophic lateral sclerosis (ALS). METHODS: The correlations of Frep parameters with clinical scores and the results of neurophysiological index (NI), MScanfit MUNE, F/M amplitude ratio (F/M%), single and paired-pulse transcranial magnetic stimulation (TMS), and triple stimulation technique (TST) studies, recorded from abductor digiti minimi (ADM) and abductor pollicis brevis (APB) muscles of 35 patients with ALS were investigated. RESULTS: Frep parameters were correlated with NI and MScanfit MUNE in ADM muscle and F/M% in both muscles. None of the Frep parameters were correlated with clinical scores or TST and TMS measures. While the CMAP amplitudes were similar in the two recording muscles, there was a more pronounced decrease of F-wave persistence in APB, probably heralding the subsequent split hand phenomenon. CONCLUSION: Our findings suggest that the presence and density of Freps are primarily related to the degree of lower motor neuron loss and show no correlation with any of the relatively extensive set of parameters for upper motor neuron dysfunction. SIGNIFICANCE: Freps are primarily related to lower motor neuron loss in ALS.

Laboratory and clinical correlates of brain atrophy in Neuro-Behçet's disease.

Background: Diagnostic evaluation of patients with parenchymal Neuro-Behçet's disease (NBD) requires magnetic resonance imaging (MRI), neuro-ophthalmologic, and neuropsychological evaluation. In this study, we aimed to find out the ideal diagnostic method that most closely reflects the progress in cognitive disability and brain atrophy in NBD. Methods: In this matched case-control study, we included patients with parenchymal NBD, Behçet's disease without neurological involvement (BD), rheumatoid arthritis, and healthy controls. Detailed ophthalmological examination, pattern-reversal visual evoked potentials (prVEP) test, optical coherence tomography (OCT), brain MRI volumetry and cognitive evaluation tests were performed. Disability status was assessed by revised EDSS. Results: Sixty-eight individuals (35 female, 33 male) were recruited. Mean ACE-R scores were significantly lower in the NBD group (NBD vs. healthy, 80±14.4, 93±4.9, p=0.002). prVEP values were similar across groups, but retinal nerve fiber layer thickness (RNFLT) were more frequently abnormal in the NBD group. We found considerable volume reduction in the brainstem, cerebellum, hippocampus, and thalamus in the NBD group. Regarding prVEP, 120 minutes P100 amplitude (p<0.001, r=0.97) and 60 minutes P100 amplitude values (p=0.006, r=0.90) were positively correlated with the total cerebral white matter volume. Conclusion: Our results confirmed previous observations on cognitive dysfunction in patients with NBD. We reported MRI volumetry data of patients with parenchymal neuro-Behçet's disease for the first time and elucidated novel brain regions with atrophy. Clinically determined scores and OCT failed to predict the status of brain atrophy. prVEP P100 amplitude may be used as a surrogate marker of cerebral white matter involvement in NBD.

Effect of the brain-derived neurotrophic factor gene Val66Met polymorphism on sensory-motor integration during a complex motor learning exercise.

The brain-derived neurotrophic factor (BDNF) gene Val66Met polymorphism may cause impairment in short-term motor learning by reducing activity-dependent BDNF expression, which causes alterations in synaptic plasticity by changing glutamatergic and GABAergic synaptic transmissions. Sensory-motor integration (SMI) plays an important role in motor learning. In this study, we investigated the role of this polymorphism on SMI during a complex motor learning practice. Forty-three healthy participants performed standardized 5-day basketball shooting exercises under supervision. Electrophysiologic SMI studies were performed before the first day exercise (T0) and after the first and fifth day exercises (T1 and T2, respectively). SMI was studied using electrical median nerve stimulation at the wrist, followed by transcranial magnetic stimulation (TMS) of the contralateral motor cortex with various inter-stimulus intervals (ISIs). Recordings were made from the thenar and forearm flexor muscles. Participants were divided into two groups according to their BDNF genotype. Group 1 consisted of 26 subjects with the Val66Val genotype and group 2 included 17 subjects with the BDNF Met allele. Group 2 had a lower increase in basketball scores at day 5. Moreover, they had higher afferent facilitation for the responses recorded from both thenar and forearm flexor muscles at T1, but these changes could not be maintained until T2. This non-persistent early hyper-responsivity of the sensory-motor cortex in subjects with the BDNF Met allele might be explained by a transient upsurge of cortical excitability to compensate the insufficient cortical plasticity during motor learning, which could be considered as a sign of lower performance in motor skill learning.

Trigeminal Hyperexcitability in Idiopathic Intracranial Hypertension: A Blink Reflex Study.

PURPOSE: To compare blink reflex examination findings in patients with idiopathic intracranial hypertension (IIH) with migraineurs and controls and to investigate the role of blink reflex data in the follow-up by evaluating their relationship with clinical symptoms. METHODS: We included 23 patients with IIH, 15 migraineurs, and 16 controls. Blink reflex was studied with bilateral paired stimulations, and the 2R2/1R2 and 2R2c/1R2c area ratios, 1R2, 2R2, 1R2c, and 2R2c latencies were compared (R2:ipsilateral R2 response, R2c:contralateral R2 response). RESULTS: 2R2/1R2 area ratios at 200, 300, and 500 ms interstimulus intervals were significantly higher in the IIH group compared with the controls, and significantly higher 2R2/1R2 area ratio at 200 ms interstimulus interval was also detected in the IIH group compared with the migraine group. Significantly shorter 2R2 latencies were found at 500 and 800 ms interstimulus intervals in IIH group compared with the migraine group and controls. Significantly higher 2R2/1R2 area ratios at 500, 800 ms, and 2R2c/1R2c area ratios at 300, 500, and 800 ms were detected in patients with IIH in remission compared with patients with attacks. CONCLUSIONS: The significant increase in R2 recovery rates in patients with IIH in remission suggests that there is an increased excitability in the trigeminal pathways. Our findings may provide a new perspective for IIH mechanism related to trigeminal hyperexcitability and evaluating new management strategies.

Assessment of Blink Reflex in Genetic Generalized Epilepsy Patients With Eyelid Myoclonia.

Eyelid myoclonia (EM) with or without absences are a rare type of generalized seizures associated with a variety of epilepsy syndromes with an unknown pathophysiology. The aim of this study was to investigate the possible contribution of the brainstem structures in this underrecognized special type of seizures. Sixteen consecutive patients with EM, diagnosed with genetic generalized epilepsy (GGE) according to International League Against Epilepsy 2010 criteria were included. Brainstem excitabilities were examined by blink reflex (BR) studies. The results of BR studies in GGE patients with EM were statistically compared with 2 control groups; namely age- and gender-matched healthy volunteers and juvenile myoclonic epilepsy (JME) patients without any absences and using similar antiepileptic drugs. There were no statistical differences between the thresholds of the BR studies and the BR recovery curves in terms of amplitudes and areas of healthy subjects, JME patients and GGE patients with EM. Our findings do not support a profound interictal hyperexcitability in the BR-related brainstem structures of the GGE patients with EM. It can be considered that EM may be associated with excitability changes of the occipital cortex and other cortical areas.

Jitter Values on Voluntary Active Periocular Muscles of Healthy Subjects with Conventional (37 mm) Concentric Needle Electrode.

INTRODUCTION: The aim of this study was to re-evaluate jitter values of healthy subjects in whom pairs of single-fiber-like potentials were recorded from voluntary activated periocular muscles using a disposable 37-mm concentric needle electrode (CNE) with 2-kHz low-cut filtering. METHODS: We reviewed the recordings of 129 subjects (85 women; 44 men; mean age, 43.8±15.3 years). The m. frontalis group included 116 subjects, and the m. orbicularis oculi group included 18 subjects. Jitter values were expressed as the mean consecutive difference (MCD) of 20 different pairs. RESULTS: The mean MCD (n=2680) was 22.5±9.7 µs (range, 5-121 µs), and the upper 95% confidence limit (CL) was 39 µs. The mean of 134 MCD values for each subject was 22.5±3.7 µs (range, 15-33 µs), and the upper 95% CL was 30 µs. The outer limit of the 18th highest MCD values out of 20 recordings for each subject was 31.3±6.5 µs (range, 18-53 µs), with an upper 95% CL of 43.3 µs. CONCLUSION: Using a conventional 37-mm CNE with 2-kHz low-cut filtering may be a cost effective alternative to a single-fiber electrode in periocular muscles if strict criteria are used for acceptable signals. Jitter values of >44 µs that were calculated from single-fiber-like action potential pairs should alert the physician regarding the possibility of neuromuscular junction disorders and constitute an indication for a further diagnostic investigation.

Autosomal Dominant Cortical Tremor, Myoclonus, and Epilepsy Syndrome mimicking Juvenile Myoclonic Epilepsy.

INTRODUCTION: Autosomal dominant cortical tremor, myoclonus, and epilepsy (ADCME) syndrome is a genetically heterogeneous and under-recognized disease characterized by tremulous movements mimicking essential tremor, myoclonus, and rare generalized tonic-clonic seizures. Here we described the clinical and electrophysiological features of three siblings with ADCME syndrome mimicking juvenile myoclonic epilepsy (JME). METHODS: Three siblings (two females and one male) diagnosed with ADCME were analyzed by electroencephalogram (EEG), somatosensory evoked potentials, and accelerometric recordings. The results were compared with 14 JME patients without tremor and 14 with essential tremor (ET). RESULTS: The shared features of the siblings were cortical tremor, myoclonia, epilepsy, migraine, and psychiatric symptoms. In all siblings, tremor had started before myoclonic epilepsy associated with 4-6 Hz generalized spike and wave discharges. The N20-P25 and P25-N35 amplitudes were substantially higher in the three siblings with ADCME. Although tremor frequencies were similar to those of the ET group, the siblings had mild interrupting low-amplitude myoclonus, suggestive of cortical tremor, in the accelerometric analysis. CONCLUSION: We presented a detailed clinical evaluation with electrophysiological confirmation of ADCME syndrome in a Turkish family. This rare clinical picture might be misdiagnosed as JME and should be kept in mind to ensure correct diagnosis and to provide a homogenous group for genetic studies.

Analysis of the tremor in juvenile myoclonic epilepsy.

PURPOSE: We aimed to investigate juvenile myoclonic epilepsy (JME) patients complaining of tremor unrelated to valproate (VPA) treatment and evaluate if there were differences between JME patients with and without tremor and essential tremor (ET) patients to exclude comorbidity. METHODS: Fifteen JME cases with the complaint of tremor, 14 JME patients without tremor, 14 patients with ET and 14 healthy subjects (HS) were included. Regularity, frequency and amplitude of the tremor and superimposed myoclonia were assessed by accelerometric analysis. Cortical SEPs evoked by the stimulation of the median nerve were recorded bilaterally. Clinical and neurophysiologic features were statistically compared between the groups. FINDINGS: Amplitude of postural tremor of the left hand was significantly increased in the ET group compared to JME patients with tremor, but there were no differences regarding to frequency. Strikingly, there were superimposed irregular, low-amplitude inconstant myoclonic jerks located to distal part of the fingers in JME group with tremor. Initial frequency of myoclonic seizures was also significantly higher in this group compared to JME patients without tremor but this difference disappeared after treatment. The group of JME with tremor had the highest N20-P25 and P25-N35 amplitudes, followed by JME without tremor, ET and HS, respectively. CONCLUSION: Tremulous hand movements in JME resembled ET, but their amplitude was lower and characterized with accompanying irregular myoclonic jerks. The presence of tremor in JME patients should be taken into consideration to create more homogeneous groups in genetic and pathophysiological studies of JME.