Ali Emre Oge

Peripheral nerve hyperexcitability syndromes.

Abstract Peripheral nerve hyperexcitability (PNH) syndromes can be subclassified as primary and secondary. The main primary PNH syndromes are neuromyotonia, cramp-fasciculation syndrome (CFS), and Morvan’s syndrome, which cause widespread symptoms and signs without the association of an evident peripheral nerve disease. Their major symptoms are muscle twitching and stiffness, which differ only in severity between neuromyotonia and CFS. Cramps, pseudomyotonia, hyperhidrosis, and some other autonomic abnormalities, as well as mild positive sensory phenomena, can be seen in several patients. Symptoms reflecting the involvement of the central nervous system occur in Morvan’s syndrome. Secondary PNH syndromes are generally seen in patients with focal or diffuse diseases affecting the peripheral nervous system. The PNH-related symptoms and signs are generally found incidentally during clinical or electrodiagnostic examinations. The electrophysiological findings that are very useful in the diagnosis of PNH are myokymic and neuromyotonic discharges in needle electromyography along with some additional indicators of increased nerve fiber excitability. Based on clinicopathological and etiological associations, PNH syndromes can also be classified as immune mediated, genetic, and those caused by other miscellaneous factors. There has been an increasing awareness on the role of voltage-gated potassium channel complex autoimmunity in primary PNH pathogenesis. Then again, a long list of toxic compounds and genetic factors has also been implicated in development of PNH. The management of primary PNH syndromes comprises symptomatic treatment with anticonvulsant drugs, immune modulation if necessary, and treatment of possible associated dysimmune and/or malignant conditions.

Cortical excitability in Duchenne muscular dystrophy

OBJECTIVE To investigate the probable cortical excitability changes in DMD by electrophysiological means. METHODS Sixteen cases with DMD, 10 age-matched control children (CC) and 10 healthy adult volunteers (AC) were studied with a transcranial magnetic stimulation (TMS) test battery composed of central conduction time, cortical silent period and paired TMS paradigm. RESULTS There were no significant differences between DMD and CC groups except for lower amplitude motor responses in DMD cases. These two groups showed a similar pattern of excitability with less short interval intracortical inhibitions and shorter silent period durations as compared to the AC subjects. CONCLUSIONS The electrophysiological tests performed in our DMD patients did not reveal abnormalities caused particularly by the disorder. SIGNIFICANCE TMS excitability studies performed in DMD boys may not provide findings other than those related to the developmental age.

Assessment of excitability at the brainstem and cortex in primary headaches with allodynia.

Purpose: The aims were to assess the excitability of motor cortex and trigeminal structures in patients with primary headaches experiencing allodynia and to investigate the alterations in interictal allodynia and blink reflex excitability after repetitive transcranial magnetic stimulation (rTMS). Methods: Patients with strictly lateralized primary headaches were included, and Allodynia Symptom Checklist was used to detect allodynia. Paired transcranial magnetic stimulation and blink reflex recovery studies were performed on both sides. Ten Hertz or sham rTMS was applied on the motor cortex in patients with interictal allodynia. Allodynic symptoms were registered quantitatively, and blink reflex study was repeated after these trials. Results: Seventeen of 34 patients with headache described allodynia. Our findings showed bilateral hyperexcitability of cortical and trigeminal structures in the allodynic group. Interictal allodynia, detected in 13 allodynic patients, improved after rTMS as compared with sham stimulation, and this effect appeared to be more evident in the late period. Conclusions: Bilateral increases in the cortical and trigeminal excitability were shown in patients with allodynia, and rTMS was effective for reducing clinical allodynia. The authors suggest that allodynic condition of the patients should be taken into account in the planning and evaluation of electrophysiological studies, and rTMS may be considered as a treatment alternative for troublesome allodynia.

Motor unit number estimation in transected peripheral nerves

Abstract Objectives: To study motor unit number estimation (MUNE) in acutely transected peripheral nerves, and to retest our previous observation which had revealed a discordance between the loss of compound muscle action potential (CMAP) size and decrease in MUNE during Wallerian degeneration. Methods: In eight patients with nine transected median or ulnar nerves, a total of 18 electrophysiological studies were performed before the complete nerve degeneration ensues. CMAP recordings and incremental MUNE studies were performed by stimulation of the nerves at the wrist level and recording from the appropriate hand muscles. The same studies repeated on the contralateral side. Results: Injury side to intact side ratios of the MUNEs were significantly higher than the CMAP ratios. Mean step areas in MUNE studies were found to be lower on the transected sides after 72 hours post-injury. Discussion: These findings support the existence of an electrophysiologically observable asynchrony in neuromuscular synapse dysfunction during Wallerian degeneration.

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.

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.

Quantitative electromyography of the frontalis muscle.

Purpose: Identification of abnormal motor unit potentials (MUP), in particular those caused by myopathic processes, is generally difficult in facial muscles because the MUPs are already low in amplitude and short in duration. Therefore, quantitative measures for the limits of abnormality are needed more frequently for these muscles, especially for the pathological processes predominantly affecting the craniofacial area. In this study, we aimed to determine some quantitative values that may help us to differentiate “myogenic” and “neurogenic” processes in periocular muscles. Methods: The frontalis muscle was examined unilaterally with multi-MUP and interference pattern analyses in 32 normal subjects, 31 patients with different types of myopathy, and 13 patients with facial palsy. Abnormality limits were calculated by using five previously suggested methods, two of which were based on group means and the other three on determining the outlier values. The sensitivity and specificity of multi-MUP and interference pattern parameters in discriminating abnormal findings by using these different methods were analyzed. Results: Statistically significant differences for all MUP parameters, except for the frequency, was found between the groups (P < 0.001). Motor unit potential duration, size index, and amplitude were the most valuable parameters for distinguishing the individual abnormalities. However, their discriminating power was higher for neuropathies than for myopathies. Interference pattern analysis was found not to have any superior sensitivity to MUP analysis. In this study, the outlier analysis that depends on the 5th to 95th percentile limits of the pooled data provided the best power for the discrimination of both neuropathies and myopathies from normal subjects. Conclusion: Multi-MUP analysis seems to be helpful in differentiating the patients with neurogenic and—to a lesser extent—myogenic facial muscle involvement.

S101. A novel automatized F-wave MUNE method: A preliminary analysis

Introduction The aim of this study was to test a novel automatized F-wave MUNE method by comparing its results with those elicited with the manual method performed in patients with amyotrophic lateral sclerosis (ALS) and healthy controls. Methods Ninety F-waves elicited with supramaximal stimuli were recorded from thenar and hypothenar muscles in 10 ALS patients and 4 healthy controls. For manual analysis, F-waves with the same amplitude, latency and shape were selected visually by the same examiner. For automatized analysis, similar signals were grouped according to latencies of negative and positive peaks and peak-to-peak amplitudes in MATLAB by using the original software developed for this study. The mean amplitudes of F-waves repeating more than once were defined as sMUPs and MUNE value for each case was calculated by dividing the CMAP amplitude by mean sMUP amplitude. Results Data of two healthy controls and 1 ALS patient were excluded from the analysis since no repeater F-waves were detected by one of the methods. sMUP and F-wave MUNE values calculated by both methods were found to be highly correlated (Spearman’s rho, p μ V and 406.55  μ V, respectively in thenar muscles and 412.53  μ V and 332.77  μ V in hypothenar muscles). Similar F-wave MUNE values were also calculated by using both methods (26.00 and 28.58, respectively in thenar muscles and 36.04 and 30.18 in hypothenar muscles). Conclusion Our automatized F-wave MUNE method seems to be promising in reflecting motor unit numbers in the hand muscles in patients with ALS and healthy controls.

T40. Comparison of MScanFit MUNE and other parameters derived from the CMAPScan in ALS patients

Introduction The aim of this study was to analyse MScanFit MUNE, D50 and step% values elicited from the CMAP scan curves of thenar and hypothenar muscles in patients with amyotrophic lateral sclerosis (ALS) and healthy controls. Methods Thirty-four ALS patients (31 definite, 1 probable and 2 possible, according to Awaji criteria) and 24 healthy controls were included. CMAP scan curves were recorded from both thenar and hypothenar muscles by applying 500 stimuli. Step% and D50 values were calculated semi-automatically and MScanFit MUNE was calculated by using the freeware version of Qtrac software. Results Mean MScanFit MUNE and D50 values were lower and step% values were higher significantly in patients (48.8, 25.0, 32.5 in thenar muscles and 66.5, 28.9, 17.0 in hypothenar muscles, respectively) as compared to healthy controls (112.5, 45.6, 4.0 in thenar muscles and 124.5, 46.6, 1.1 in hypothenar muscles; p p Conclusion Step% and MScanFit MUNE are parameters correlated with each other and they are sensitive tools in revealing the severities and the courses of the electrophysiological abnormalities in ALS.

F52. Repeater F-waves: Electrophysiologic manifestations of upper or lower motor neuron involvement?

Introduction The aim of this study is to compare repeater F-wave parameters with CMAP amplitudes recorded from the hand muscles (as indicators of the amount of lower motor neuron [LMN] loss) and with the triple stimulation technique (TST) ratios in the same muscles (as indicators of upper motor neuron [UMN] involvement) in 19 patients with amyotrophic lateral sclerosis (ALS). Methods Ninety F-waves were recorded from thenar and hypothenar muscles by supramaximal stimuli applied to the relevant nerves at the wrist level. Repeater F-waves (F rep ) were visually defined as those presented with the same amplitude, latency and shapes. Repeater neuron (RN) index, F rep index, persistances of F-waves, F/M amplitude ratio and the neurophysiologic index (NI) were calculated. By depending our laboratory normals, TST ratio values lower than 82% and 86% were accepted as abnormal showing UMN involvement in thenar and hypothenar muscles respectively. Results TST ratios were abnormal in 13 thenar and 11 hypothenar muscles. None of the F rep parameters showed any significant relationship with the abnormal TST ratios, except the lower F rep index in thenar muscles, in patients with UMN involvement according to low TST ratios. However, there was a strong negative correlation with the CMAP amplitudes and F rep index and RN index values in hypothenar muscle (Spearman’s rho, p Conclusion These findings imply that repeater F waves might be a manifestation of LMN loss more than being a result of UMN involvement.