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ID 323 – Shortening of the cutaneous silent period duration in tibialis anterior after fatiguing eccentric exercise
Abstracts / Clinical Neurophysiology 127 (2016) e18–e132
ID 323 – Shortening of the cutaneous silent period duration in tibialis anterior after fatiguing eccentric exercise—O.C. Banea, J. Casanova-Molla, M. Morales, C. Cabib, R. Arca, M. Brum, J. VallsSolé (Department of Neurology, Hospital Clinic, Barcelona, Spain) Objective: Muscle afferent feedback (presumably mainly of spindle origin) contributes to the maintenance of alpha motoneuron firing during sustained muscle contraction. We aimed at investigating how a unilateral fatiguing eccentric exercise involving the tibialis anterior (TA) affects inhibitory control of muscle activity. Methods: In 8 healthy subjects, we assessed the TA silent period (SP) to cortical magnetic stimuli (round coil) and to cutaneous nerve electrical stimulation (superficial peroneal nerve at the ankle) before and after 5 min of eccentric exercise. Results: At baseline, SP duration was variable among subjects but cortical SP was always longer than cutaneous SP (111.6 ± 13.8 ms vs. 37.3 ± 10.2 ms). After exercise, there was a slight increase in background EMG activity. The cutaneous SP shortened significantly (24.3 ± 7.3 ms) at the expenses of onset latency delay (98.7 ± 14.0 ms in baseline to 112.2 ± 11.9 ms after exercise). There were no significant changes in cortical SP after exercise (106.2 ± 18.1 ms). Conclusions: Eccentric exercise leads to a delay in onset latency of the cutaneous SP with no changes in cortical SP. An effect of fatigue on small nerve fibers, which are known to contribute to the onset of cutaneous SP, may partly explain our results. doi:10.1016/j.clinph.2015.11.444
e131
ID 351 – Prognostic significance of A-waves as an isolated abnormity of nerve conduction studies—E. Vlckova, J. Bednarik (Central European Institute of Technology, Masaryk University, Brno, Czech Republic, Department of Neurology, University Hospital, Brno, Czech Republic) Background: A-waves represent a frequent type of late responses, generally considered as a non-specific electrophysiological finding with an unclear significance, particularly in tibial nerves. The aim of our study was to examine, if the occurrence of A-waves may predict increased probability of the development of other electrophysiological abnormalities in corresponding nerves in the future. Methods: The occurence of A-waves was assessed in 126 patients, who underwent repeated neurophysiological examination of the same part of the body at least 12 month apart and whose initial examination was assessed as normal (or with occurence of A-waves as the only abnormality). Results: New abnormality (polyneuropathy, mononeuropathy, radiculopathy) in a corresponding nerve at the second examination was found in 100% of ulnar, median and peroneal nerves with the occurence of A-waves at initial conduction studies, and in 62% of such a tibial nerves. In the distribution of nerves with no initial A-waves, new abnormality in second examination was found in 10%, 11%, 24% and 22% of median, ulnar, peroneal and tibial nerves, respectively (p < 0.001). Conclusions: Occurence of A-waves (even in tibial nerves) significantly increases the probability of the development of clear neurophysiological abnormalities in the future. doi:10.1016/j.clinph.2015.11.446
ID 346 – Transthyretin familial amyloid polyneuropathy (TTRFAP): Efficacy of liver transplant versus tafamidis in nerve fiber function—J. Castro, I. Conceição, M. de Carvalho (Translational and Clinical Physiology Unit, Instituto de Medicina Molecular, Faculty of Medicine, Lisbon, Portugal, Department of Neurosciences, Centro Hospitalar Lisboa Norte – Hospital de Santa Maria, Lisbon, Portugal) Objective: To evaluate the effect of Tafamidis versus liver transplant in nerve conduction studies of TTR-FAP patients over 24 months. Methods: Nerve conduction data from 48 stage I TTR-FAP patients was analysed retrospectively for 24 months after treatment. 26 patients (37.73 ± 9.19 years) submitted to liver transplant were compared to 22 patients on Tafamidis (40.00 ± 8.74). Sympathetic skin response, Motor and Sensory composed scores were obtained after respective summing of nerve amplitudes. Disease duration to baseline and Karnofsky index were also evaluated. Progression was evaluated using a Repeated Measures ANOVA. Results: Sensory composed score in the Tafamidis group was the single measure to progress significantly on the first 12 months, stabilizing afterwards. No other significantly differences were found between groups over time. Conclusions: Efficacy of Tafamidis on nerve fiber function of TTRFAP patients, seems to be similar to liver transplant, over 2 years, despite a slight progression on the first 6 months with stabilization afterwards. These findings are consistent with the clinical stabilization reported in the literature with both treatments. Key message: Efficacy of tafamidis is similar to liver transplant in the stabilization of the neuropathy.
ID 397 – EMG and clinical outcome of Leechavenvong’s transfer, preliminary results—S. Brusakova b, I. Humhej a, J. Cee a, M. Sames a (a Neurosurgery, Masaryk Hospital, Ústí nad Labem, Czech Republic, b Neurology, Masaryk Hospital, Ústí nad Labem, Czech Republic) Purpose: The aim of the study is to analyse the results of Leechavenvong’s transfer – long head triceps branch of radial nerve to axillary nerve neurotization. Matherial and methods: Group of 5 patients (4 men, 1 woman, mean age 44, mean time from injury to surgery 5 months), who underwent Leechavenvong’s transfer in last two years was analysed. The main inclusion criterium was irreparable axillary nerve injury (simple or as a part of brachial plexus injury) with complete dennervation in deltoid muscle preoperatively. We assessed motor recovery according to MRC Scoring system and EMG reinnervation signs every 3 months after surgery. We set the total follow-up time for 18 months. Results: All patients have evidence of partial muscle reinnervation on electrodiagnostic studies after 6 months. There is no impairment of the triceps brachii function. Conclusion: Our preliminary results in small group show that long head triceps branch of radial to axillary nerve neurotization can successfully provide reinnervation. We found better outcome by patients with the first signs of reinnervation in 3 months after surgery. doi:10.1016/j.clinph.2015.11.447
doi:10.1016/j.clinph.2015.11.445
ID 323 – Shortening of the cutaneous silent period duration in tibialis anterior after fatiguing eccentric exercise—O.C. Banea, J. Casanova-Molla, M. Morales, C. Cabib, R. Arca, M. Brum, J. VallsSolé (Department of Neurology, Hospital Clinic, Barcelona, Spain) Objective: Muscle afferent feedback (presumably mainly of spindle origin) contributes to the maintenance of alpha motoneuron firing during sustained muscle contraction. We aimed at investigating how a unilateral fatiguing eccentric exercise involving the tibialis anterior (TA) affects inhibitory control of muscle activity. Methods: In 8 healthy subjects, we assessed the TA silent period (SP) to cortical magnetic stimuli (round coil) and to cutaneous nerve electrical stimulation (superficial peroneal nerve at the ankle) before and after 5 min of eccentric exercise. Results: At baseline, SP duration was variable among subjects but cortical SP was always longer than cutaneous SP (111.6 ± 13.8 ms vs. 37.3 ± 10.2 ms). After exercise, there was a slight increase in background EMG activity. The cutaneous SP shortened significantly (24.3 ± 7.3 ms) at the expenses of onset latency delay (98.7 ± 14.0 ms in baseline to 112.2 ± 11.9 ms after exercise). There were no significant changes in cortical SP after exercise (106.2 ± 18.1 ms). Conclusions: Eccentric exercise leads to a delay in onset latency of the cutaneous SP with no changes in cortical SP. An effect of fatigue on small nerve fibers, which are known to contribute to the onset of cutaneous SP, may partly explain our results. doi:10.1016/j.clinph.2015.11.444
e131
ID 351 – Prognostic significance of A-waves as an isolated abnormity of nerve conduction studies—E. Vlckova, J. Bednarik (Central European Institute of Technology, Masaryk University, Brno, Czech Republic, Department of Neurology, University Hospital, Brno, Czech Republic) Background: A-waves represent a frequent type of late responses, generally considered as a non-specific electrophysiological finding with an unclear significance, particularly in tibial nerves. The aim of our study was to examine, if the occurrence of A-waves may predict increased probability of the development of other electrophysiological abnormalities in corresponding nerves in the future. Methods: The occurence of A-waves was assessed in 126 patients, who underwent repeated neurophysiological examination of the same part of the body at least 12 month apart and whose initial examination was assessed as normal (or with occurence of A-waves as the only abnormality). Results: New abnormality (polyneuropathy, mononeuropathy, radiculopathy) in a corresponding nerve at the second examination was found in 100% of ulnar, median and peroneal nerves with the occurence of A-waves at initial conduction studies, and in 62% of such a tibial nerves. In the distribution of nerves with no initial A-waves, new abnormality in second examination was found in 10%, 11%, 24% and 22% of median, ulnar, peroneal and tibial nerves, respectively (p < 0.001). Conclusions: Occurence of A-waves (even in tibial nerves) significantly increases the probability of the development of clear neurophysiological abnormalities in the future. doi:10.1016/j.clinph.2015.11.446
ID 346 – Transthyretin familial amyloid polyneuropathy (TTRFAP): Efficacy of liver transplant versus tafamidis in nerve fiber function—J. Castro, I. Conceição, M. de Carvalho (Translational and Clinical Physiology Unit, Instituto de Medicina Molecular, Faculty of Medicine, Lisbon, Portugal, Department of Neurosciences, Centro Hospitalar Lisboa Norte – Hospital de Santa Maria, Lisbon, Portugal) Objective: To evaluate the effect of Tafamidis versus liver transplant in nerve conduction studies of TTR-FAP patients over 24 months. Methods: Nerve conduction data from 48 stage I TTR-FAP patients was analysed retrospectively for 24 months after treatment. 26 patients (37.73 ± 9.19 years) submitted to liver transplant were compared to 22 patients on Tafamidis (40.00 ± 8.74). Sympathetic skin response, Motor and Sensory composed scores were obtained after respective summing of nerve amplitudes. Disease duration to baseline and Karnofsky index were also evaluated. Progression was evaluated using a Repeated Measures ANOVA. Results: Sensory composed score in the Tafamidis group was the single measure to progress significantly on the first 12 months, stabilizing afterwards. No other significantly differences were found between groups over time. Conclusions: Efficacy of Tafamidis on nerve fiber function of TTRFAP patients, seems to be similar to liver transplant, over 2 years, despite a slight progression on the first 6 months with stabilization afterwards. These findings are consistent with the clinical stabilization reported in the literature with both treatments. Key message: Efficacy of tafamidis is similar to liver transplant in the stabilization of the neuropathy.
ID 397 – EMG and clinical outcome of Leechavenvong’s transfer, preliminary results—S. Brusakova b, I. Humhej a, J. Cee a, M. Sames a (a Neurosurgery, Masaryk Hospital, Ústí nad Labem, Czech Republic, b Neurology, Masaryk Hospital, Ústí nad Labem, Czech Republic) Purpose: The aim of the study is to analyse the results of Leechavenvong’s transfer – long head triceps branch of radial nerve to axillary nerve neurotization. Matherial and methods: Group of 5 patients (4 men, 1 woman, mean age 44, mean time from injury to surgery 5 months), who underwent Leechavenvong’s transfer in last two years was analysed. The main inclusion criterium was irreparable axillary nerve injury (simple or as a part of brachial plexus injury) with complete dennervation in deltoid muscle preoperatively. We assessed motor recovery according to MRC Scoring system and EMG reinnervation signs every 3 months after surgery. We set the total follow-up time for 18 months. Results: All patients have evidence of partial muscle reinnervation on electrodiagnostic studies after 6 months. There is no impairment of the triceps brachii function. Conclusion: Our preliminary results in small group show that long head triceps branch of radial to axillary nerve neurotization can successfully provide reinnervation. We found better outcome by patients with the first signs of reinnervation in 3 months after surgery. doi:10.1016/j.clinph.2015.11.447
doi:10.1016/j.clinph.2015.11.445