P63-S Insidious neuromuscular deterioration in polio survivors demonstrated by CMAP scan analysis

P63-S Insidious neuromuscular deterioration in polio survivors demonstrated by CMAP scan analysis

e110 Abstracts / Clinical Neurophysiology 130 (2019) e21–e116 P52-S State-dependent changes in cortical reactivity: comparison between direct cortic...

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Abstracts / Clinical Neurophysiology 130 (2019) e21–e116

P52-S State-dependent changes in cortical reactivity: comparison between direct cortical and peripheral stimulation—Simone Sarasso a, Silvia Casarotto a, Matteo Fecchio a, Camilla Derchi a, Alice Mazza a, Sasha D’Ambrosio a, Alessandro Viganò a, Adenauer Girardi Casali b, Renzo Comolatti b, Angela Comanducci a, Mario Rosanova a, Marcello Massimini a, Sara Parmigiani a,* (a University Of Milan, Milano, Italy, b Universidade Federal de São Paulo, Sao Jose dos Campos, Brazil) ⇑

Corresponding author.

Introduction: Peripheral as well as direct cortical stimulations have been classically used to probe the reactivity of thalamocortical circuits across brain states, showing consistent state-dependent modifications. Methods: Here we aim at directly comparing state-dependent changes across the wake/sleep cycle of the electroencephalographic (EEG) responses to transcranial magnetic stimulation (TMS – applied over premotor and parietal areas) and to electrical median nerve stimulation (EMNS - applied at an intensity able to reproducibly elicit thumb movements) in two groups of 8 healthy individuals each. Results: By tuning stimulation parameters, we roughly equalized the strength of brain activation elicited by TMS and EMNS during wakefulness and achieved a similar (p = 0.8) overall (0–600 ms) global mean field power (GMFP). The time-course of wakefulness GMFP significantly peaked (p < 0.05) at 0–50 ms for TMS and at 250–300 ms for EMNS. Compared to wakefulness, during NREM sleep: (1) the early (0–80 ms) as well as the late (80–600 ms) evoked EEG response significantly increased for TMS and decreased for EMNS (p < 0.05); (2) these changes were associated to specific voltage topographies for TMS and EMNS; and (3) the overall spatiotemporal complexity decreased for both stimulation approaches. Conclusions: Despite a common reduction of complexity during sleep, brain activation elicited by the two stimulation approaches reveals different state-dependent changes, highlighting the presence of cortical bistability in the case of TMS and of subcortical gating in the case of EMNS. doi:10.1016/j.clinph.2019.04.588

P53-S The effect of sleep deprivation on the parameters of visual evoked potentials in healthy volunteers—Rafal Rola *, Anna Kozica, Krzysztof Rozanowski (Military Institute of Aviation Medicine, Warsaw, Poland) ⇑

Results: No significant differences in the N75 and P100 latencies and amplitudes were found. N145 response latencies were significantly longer after 24 and 48 hours of sleep deprivation. Conclusions: 24 and 48 hours sleep deprivation induces prolongation of the N145 response, which may be a neurophysiological biomarker of visual perception disturbances in sleep deprivated persons. doi:10.1016/j.clinph.2019.04.589

P54-S Somatosensory and motor phenomena elicited by electrical stimulation of hippocampus: insight into the ictal network— Torsten Vinding Merinder a,*, György Rásonyi b, Ioannis Tsiropoulos c, Martin Fabricius b, Sándor Beniczky a,d a ( Department of Clinical Neurophysiology, Aarhus University b Hospital, Aarhus, Denmark, Department of Clinical Neurophysiology, Copenhagen University Hospital Rigshospitalet, Denmark, c Department of Neurology, Copenhagen University Hospital Rigshospitalet, Denmark, d Department of Clinical Neurophysiology, Danish Epilepsy Centre, Dianalund and Department of Clinical Medicine, Aarhus University, Aarhus, Denmark) ⇑

Corresponding author.

Background: Direct electrical stimulation of the cortex elicits responses according to the physiology of the stimulated area. In patients with drug resistant epilepsy evaluated for surgical therapy, this method is used for mapping the eloquent cortex and for triggering the patients’ habitual seizures, using intracerebral electrodes. Up to 11% of patients with mesial temporal lobe epilepsy have somatosensory aura, although these structures do not have any somatosensory physiological representation. Material and methods: We present the case of a patient with left mesial temporal lobe epilepsy who had somatosensory auras on the right side. Direct electrical stimulation of the left hippocampus, at 50 Hz, elicited the somatosensory auras, while stimulation at 1 Hz elicited myoclonic jerks time-locked to the stimulus. Results and conclusions: These unusual responses to cortical stimulation suggest that in patients with epilepsy aberrant neural networks are established, which have an essential role in ictogenesis. doi:10.1016/j.clinph.2019.04.590

Corresponding author.

Background: Sleep deprivation causes a number of negative effects on cognitive functions. It disturbs the processes of attention and concentration. It reduces visual vigilance and reduces the ability to recognize complex visual information. The aim of our study was to determine the effect of 48 hours sleep deprivation on visual processes evaluated with visual evoked potentials Material and methods: We examined 17 healthy volunteers aged from 21 to 24 years old, 7 men and 10 women who underwent controlled sleep deprivation for 48 hours. Basic vital parameters were monitored in all subjects. Visual evoked potentials were induced before and after 24 and 48 hours of sleep deprivation. The study was approved by the local bioethics committee. All participants gave written consent to participation in the study. Latencies and amplitudes of N75, P100 and N145 responses were analyzed.

P63-S Insidious neuromuscular deterioration in polio survivors demonstrated by CMAP scan analysis—Bahar Erbas a, Nermin Gorkem Sirin a,*, Emel Oguz Akarsu a, Elif Kocasoy Orhan a, Mehmet Baris Baslo a, Aysegul Ketenci b, Ali Emre Oge a (a Istanbul University Istanbul Medical Faculty, Neurology Department, Istanbul, Turkey, b Istanbul University Istanbul Medical Faculty, Physical Therapy and Rehabilitation Department, Istanbul, Turkey) ⇑

Corresponding author.

Background: This study aimed to explore the subtle motor unit (MU) changes in asymptomatic muscles of poliomyelitis survivors (PS) using CMAP Scan analysis. Material and method: Nineteen PS cases and 21 controls were recruited. CMAP Scan recordings were obtained from asymptomatic thenar and hypothenar muscles. CMAP Scan parameters indicating nerve excitability [stimulus intensities producing 50%, 95% and 5%

Abstracts / Clinical Neurophysiology 130 (2019) e21–e116

of the CMAP amplitude (SI%5, SI%50, SI%95), absolute range width (ARW) (SI%95-SI%5), relative width (RW) (SI95 SI5)/SI5], all step parameters and D50 which reflect the MU motor unit loss and reinnervation were analyzed. The new motor unit number estimation (MUNE) method, MscanFit was also calculated. Results: There were no significant differences in ages, maximum CMAP amplitudes and MScanFit MUNE between the groups. PS group median and ulnar D50 values (46.76 ± 10.98, 46.19 ± 12.42 respectively) were lower than control group (37.21 ± 17.37, 36.44 ± 11.99) (p < 0.05). Median nerve,excitability parameters of patients (SI 5%; 14.81 ± 6.97, SI 50%; 19.07 ± 9.2, SI 95%; 24.06 ± 11.52), ARW (9.26 ± 5.79), RW (0.65 ± 0.31) were higher than those of the controls (SI 5%; 9.64 ± 2.57, SI 50%; 11.64 ± 3.27, SI 95%; 13.64 ± 3.66, ARW; 4.00 ± 1.56, RW; 0.42 ± 0.13) (p < 0.05). Median and ulnar nerve step size parameters, step number and step% in the patients were also significantly higher (p < 0.05). Conclusions: CMAP Scan can show reduced axonal excitability and reveal insidious MU loss and reinnervation in presumably unaffected muscles of PS, regardless of the decrease in CMAP amplitudes or a significant reduction in MUNE values. doi:10.1016/j.clinph.2019.04.591

P64-S Reduced phosphene prevalence in ALS despite normal threshold—Bülent Cengiz *, Halt Fidancı, Hande Baltacı, Ece Türksoy, Reha Kuruog˘lu (Gazi University Medical Faculty Department of Neurology Neurology Division, Ankara, Turkey) ⇑

Corresponding author.

Introduction: Although ALS is one of the most common degenerative diseases of the motor neuron system, symptoms, and findings of the disease are not always restricted solely to the motor system. Certain clinical and electrophysiological findings observed in ALS patients imply some sensorial abnormalities. The aim of this study to investigate whether visual sensorial involvement occurs in ALS patients. For this, we investigated occipital cortex excitability with the phosphene threshold method. Method: Twenty-one ALS patients and 16 healthy controls were included in the study. Visual cortex TMS was performed using a standard round coil. TMS was performed in a semi-dark room. Eyes of participants were closed with an eye mask. Coil was placed vertically to 7 cm above the inion. Right, and left occipital cortices were stimulated at the same session. Short interval intracortical inhibition (SICI) and resting motor threshold (RMT) were also studied as well as ALSFRS-R scores in patients. Results: Phosphenes were elicited in 13 (81.2%) of controls, 9 (42.9%) of ALS patients (p = 0.041). Mean phosphene thresholds obtained with the occipital TMS was no difference between two groups (p > 0.05). No correlation was found between the phosphene threshold and ALSFRS-R scores, SICI, RMT (p > 0.05) Discussion: Results of this study indicated a reduced prevalence of phosphene in connection with decreased occipital cortex excitability in ALS patients for the first time. This finding may indicate the loss of function of V1, V2/V3 or abnormal connectivity between V1 and V2/ V3, regardless of clinical status or motor cortex excitability of the patients. doi:10.1016/j.clinph.2019.04.592

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P65-S Impaired short and long latency afferent inhibition in ALS—Bülent Cengiz *, Halit Fidancı, Yeliz Kıyak Keçeli, Hande Baltacı, Reha Kuruog˘lu (Gazi University Medical Faculty, Ankara, Turkey) ⇑

Corresponding author.

Objective: To test the hypothesis of impaired cholinergic activity in amyotrophic lateral sclerosis (ALS), we studied the short latency (SAI) and long latency (LAI) afferent inhibition. Methods: Transcranial magnetic stimulation (TMS) was delivered to the left M1. Central motor conduction time (CMCT) and motor action potential (MEP) latency were obtained. Right ulnar nerve was stimulated at the wrist preceding the TMS 21 ms for SAI and 200 ms for LAI. Results: Twenty-one ALS patients and 17 healthy controls participated in the study. Mean CMCT (p = 0.009) and MEP latency (p = 0.02) were significantly prolonged in patients. The SAI paradigm resulted in inhibition in all healthy individuals (100%), whereas inhibition was observed in 13 out of 21 (62%) patients. Mean SAI and LAI (p < 0.05) values were significantly reduced in patients. Conclusion: LAI as well as SAI, modulated by the cholinergic system, are impaired in ALS, probably unrelated to increased cortical excitability or cognitive dysfunction. doi:10.1016/j.clinph.2019.04.593

P66-S Corticospinal function in poliomyelitis survivors—Nermin Gorkem Sirin a,*, Bahar Erbas a, Gulsah Gula b, Emel Oguz-Akarsu a, Hava Ozlem Dede a, Elif Kocasoy-Orhan a, Mehmet Baris Baslo a, Aysegul Ketenci b, Halil Atilla Idrisoglu a, Ali Emre Oge a (a Istanbul University, Istanbul Faculty of Medicine, Department of Neurology, Istanbul, Turkey, b Istanbul University, Istanbul Faculty of Medicine, Department of Physical Medicine and Rehabilitation, Istanbul, Turkey) ⇑

Corresponding author.

Background: Poliomyelitis survivors (PS) become candidates to post-polio syndrome (PPS) in their later lives. The mechanism of PPS has been suggested to be multifactorial involving cortical, spinal and peripheral mechanisThe aim of this study was to evaluate TMS parameters in PS and to compare them with those of amyotrophic lateral sclerosis (ALS) patients and controls. Material and methods: Single and paired TMS, contralateral and ipsilateral silent period (SP) and triple stimulation technique (TST) were performed by recording from abductor digiti minimi (ADM) and abductor pollicis brevis (APB) muscles of 18 PS, 31 ALS patients and 21 controls. The results were compared with mixed ANOVA and nonparametric independent tests. Results: No significant difference was present for within and between subject factors except those for the different interstimuli intervals. Resting motor threshold and MEP/M% in ADM, MEP amplitudes and latencies and TST% in both ADM and APB were significantly different. In posthoc analyses, MEP latencies were higher and TST% were lower in both ADM and APB in ALS group (20.7 ± 4.2 ms, 22.4 ± 5.0 ms, 83.1 ± 42.2, 72.3 ± 29.9) as compared to PS (18.3 ± 1.0 ms, 19.2 ± 2.0 ms, 101.6 ± 15.9, 98.1 ± 14.9), MEP/M% in ADM were lower in PS group (56.0 ± 13.4) as compared to controls