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146. Electroencephalographic abnormalities in spinocerebellar ataxia type 2 Cuban patients
Society Proceedings / Clinical Neurophysiology 119 (2008) e99–e164
We conclude that nerve conduction studies and F wave differentiate between GBS and CIDP patients. doi:10.1016/j.clinph.2008.04.160
145. Heat activation generates different effects on nerve conduction studies in patients with carpal tunnel syndrome and normal subjects—H. Herna´ndez, J.G. Gutie´rrez, G. Verea, E. Mendoza (Cuba) The effects of heat activation on median nerve conduction studies (NCS) in patients with carpal tunnel syndrome (CTS) are not clearly known. This paper is aimed to evaluate whether heat activation generates different effects on NCS in CTS patients and normal controls. Conventional NCS were recorded in 20 patients with electrophysiological confirmation of mild CTS and 20 age matched healthy subjects. Distal latencies and relative amplitudes of sensory and motor responses were measured in the median and ulnar nerves at 320 and 450 celsius skin temperatures. The percentage of change induced by heat activation on NCS was quantified for each variable. These were compared between normal subjects and CTS patients. The results show that heat activation (1) is significantly reduced: sensory latencies in the wrist-palm, palm-II digit and wrist-IV digit median nerve segments and in the wrist-IV digit segment of the ulnar nerve, (2) induced no significant differences between the temperature effects induced on latencies, (3) induced similar changes on median to ulnar latency difference, (4) reduced the amplitude of motor and sensory potentials in both groups but this was only significant in CTS group. These suggest that heat activation is not useful to increase the sensitivity of NCS in patients with mild CTS.
e135
147. The membrane bilayer pollution as possible cause of epilepsy—J.L. Herna´ndez Ca´ceres, R. Soria Risco, C.M. Martı´nez Ortiz, K. Valde´s Crespo, M. Sautie´ Castellanos (Cuba) For many years the idea has prevailed of a misbalance between synaptic excitation and inhibition as the cause of epilepsy. However, evidences do not support this idea. On the other hand, Altrup et al. postulated that epileptic activity arises as result of a ‘‘pollution” of the cell membrane with amphiphilic substances experiments carried out mainly on invertebrate nervous system. Following evidences with observations in humans and other mammals could support the ‘‘Membrane Pollution Hypothesis”. (1) The APOE 4 genotype is associated to an earlier onset and higher severity of different types of epilepsies. (2) Epilepsy induced in different experimental models leads to changes in brain lipid composition and faster lipid breakdown. (3) Valproic acid treatment leads to favorable changes in lipid metabolism. (4) Refractory epilepsies are associated to disturbances in glycoprotein P, responsible for the conveyance of amphiphilic substances into neurons (5) Ketogenic diet does alleviate untractable epilepsies, probably via acetin incorporation into the lipid bilayer. (6) Recent theoretical studies suggest that a mechanical soliton accompanies the action potential propagation, and lipid bilayer mechanical properties do influence this mechanism. This hypothesis is compatible with observations not only in invertebrate, but also in mammals’ brains. It may help in understanding epilepsy mechanisms and its treatment. doi:10.1016/j.clinph.2008.04.163
148. Survival analysis for the estimation of age at onset in spinocerebellar ataxia type 2 Cuban patients—L.M. Almaguer, N.F. Santos, Y.A. Rodrı´guez, Y.Z. Gonza´lez, L.P. Vela´zquez, E.G. Martı´nez, D.A. Cuello (Cuba)
doi:10.1016/j.clinph.2008.04.161
146. Electroencephalographic abnormalities in spinocerebellar ataxia type 2 Cuban patients—R.M. Pe´rez, L.C. Vela´zquez, N. Canales, L.E. Almaguer, Y. Medrano, G. Sa´nchez (Cuba) Spinocerebellar ataxia type 2 (SCA2) belongs to a group of neurodegenerative disorders of autosomal dominant inheritance. There are no published materials in which EEG alterations are described in this disease. In this study, a group of 51 patients with SCA2 molecularly confirmed were studied by means of conventional and quantitative EEG technique. These show that in 37 (72.5%) were found abnormal increases of the theta absolute and relative power, as well as diminishment of the total mean frequency. From this sample, 31 (83.7%) showed a wide-spread theta slow activity, and 6 (16.8%) had focal theta activity mostly in central and posterior brain areas. These results make evident electroencephalographic disturbances in SCA2 patients not described before, opening the way to new research in this field. doi:10.1016/j.clinph.2008.04.162
In this paper, we further characterize the association between CAG repeat length and age at onset in spinocerebellar ataxia type 2, and to determine the SCA2 gene penetrance. A large group of 870 affected and asymptomatic at-risk individuals with a CAG repeat expansion was analyzed. This was composed of 402 at-risk asymptomatic and 468 affected with a CAG repeat length of 25-79 units. Kaplan–Meier analysis has offered curves for determining the probability of onset at a given age, for each CAG repeat length is in the 34–45 range. The Kaplan–Meier curves were significantly different (p < 0,001), with fairly narrow 95% confidence intervals (95% CI) (±10%). No more than a fraction of those with a CAG repeat size of 32–36 showed signs or symptoms of SCA2 within a normal life span; complete penetrance was observed for CAG repeat sizes of ?37 units. We conclude that the CAG repeat number at the expanded alleles is the main determinant of the age at onset in SCA2 patients. There is a reduced penetrance range for SCA2 gene between 32 and 36 CAG repeats. These information concerning the odds of being affected with a particular CAG repeat length, and may be valuable in predictive-testing programs. doi:10.1016/j.clinph.2008.04.164
We conclude that nerve conduction studies and F wave differentiate between GBS and CIDP patients. doi:10.1016/j.clinph.2008.04.160
145. Heat activation generates different effects on nerve conduction studies in patients with carpal tunnel syndrome and normal subjects—H. Herna´ndez, J.G. Gutie´rrez, G. Verea, E. Mendoza (Cuba) The effects of heat activation on median nerve conduction studies (NCS) in patients with carpal tunnel syndrome (CTS) are not clearly known. This paper is aimed to evaluate whether heat activation generates different effects on NCS in CTS patients and normal controls. Conventional NCS were recorded in 20 patients with electrophysiological confirmation of mild CTS and 20 age matched healthy subjects. Distal latencies and relative amplitudes of sensory and motor responses were measured in the median and ulnar nerves at 320 and 450 celsius skin temperatures. The percentage of change induced by heat activation on NCS was quantified for each variable. These were compared between normal subjects and CTS patients. The results show that heat activation (1) is significantly reduced: sensory latencies in the wrist-palm, palm-II digit and wrist-IV digit median nerve segments and in the wrist-IV digit segment of the ulnar nerve, (2) induced no significant differences between the temperature effects induced on latencies, (3) induced similar changes on median to ulnar latency difference, (4) reduced the amplitude of motor and sensory potentials in both groups but this was only significant in CTS group. These suggest that heat activation is not useful to increase the sensitivity of NCS in patients with mild CTS.
e135
147. The membrane bilayer pollution as possible cause of epilepsy—J.L. Herna´ndez Ca´ceres, R. Soria Risco, C.M. Martı´nez Ortiz, K. Valde´s Crespo, M. Sautie´ Castellanos (Cuba) For many years the idea has prevailed of a misbalance between synaptic excitation and inhibition as the cause of epilepsy. However, evidences do not support this idea. On the other hand, Altrup et al. postulated that epileptic activity arises as result of a ‘‘pollution” of the cell membrane with amphiphilic substances experiments carried out mainly on invertebrate nervous system. Following evidences with observations in humans and other mammals could support the ‘‘Membrane Pollution Hypothesis”. (1) The APOE 4 genotype is associated to an earlier onset and higher severity of different types of epilepsies. (2) Epilepsy induced in different experimental models leads to changes in brain lipid composition and faster lipid breakdown. (3) Valproic acid treatment leads to favorable changes in lipid metabolism. (4) Refractory epilepsies are associated to disturbances in glycoprotein P, responsible for the conveyance of amphiphilic substances into neurons (5) Ketogenic diet does alleviate untractable epilepsies, probably via acetin incorporation into the lipid bilayer. (6) Recent theoretical studies suggest that a mechanical soliton accompanies the action potential propagation, and lipid bilayer mechanical properties do influence this mechanism. This hypothesis is compatible with observations not only in invertebrate, but also in mammals’ brains. It may help in understanding epilepsy mechanisms and its treatment. doi:10.1016/j.clinph.2008.04.163
148. Survival analysis for the estimation of age at onset in spinocerebellar ataxia type 2 Cuban patients—L.M. Almaguer, N.F. Santos, Y.A. Rodrı´guez, Y.Z. Gonza´lez, L.P. Vela´zquez, E.G. Martı´nez, D.A. Cuello (Cuba)
doi:10.1016/j.clinph.2008.04.161
146. Electroencephalographic abnormalities in spinocerebellar ataxia type 2 Cuban patients—R.M. Pe´rez, L.C. Vela´zquez, N. Canales, L.E. Almaguer, Y. Medrano, G. Sa´nchez (Cuba) Spinocerebellar ataxia type 2 (SCA2) belongs to a group of neurodegenerative disorders of autosomal dominant inheritance. There are no published materials in which EEG alterations are described in this disease. In this study, a group of 51 patients with SCA2 molecularly confirmed were studied by means of conventional and quantitative EEG technique. These show that in 37 (72.5%) were found abnormal increases of the theta absolute and relative power, as well as diminishment of the total mean frequency. From this sample, 31 (83.7%) showed a wide-spread theta slow activity, and 6 (16.8%) had focal theta activity mostly in central and posterior brain areas. These results make evident electroencephalographic disturbances in SCA2 patients not described before, opening the way to new research in this field. doi:10.1016/j.clinph.2008.04.162
In this paper, we further characterize the association between CAG repeat length and age at onset in spinocerebellar ataxia type 2, and to determine the SCA2 gene penetrance. A large group of 870 affected and asymptomatic at-risk individuals with a CAG repeat expansion was analyzed. This was composed of 402 at-risk asymptomatic and 468 affected with a CAG repeat length of 25-79 units. Kaplan–Meier analysis has offered curves for determining the probability of onset at a given age, for each CAG repeat length is in the 34–45 range. The Kaplan–Meier curves were significantly different (p < 0,001), with fairly narrow 95% confidence intervals (95% CI) (±10%). No more than a fraction of those with a CAG repeat size of 32–36 showed signs or symptoms of SCA2 within a normal life span; complete penetrance was observed for CAG repeat sizes of ?37 units. We conclude that the CAG repeat number at the expanded alleles is the main determinant of the age at onset in SCA2 patients. There is a reduced penetrance range for SCA2 gene between 32 and 36 CAG repeats. These information concerning the odds of being affected with a particular CAG repeat length, and may be valuable in predictive-testing programs. doi:10.1016/j.clinph.2008.04.164