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P 234. Transcranial direct current stimulation and Alzheimer’s disease
e178
Society Proceedings / Clinical Neurophysiology 124 (2013) e39–e187
Medicine, Departments of Neuropsychiatry, Assiut, Egypt, b Assiut University Faculty of Medicine, Assiut, Egypt, c UCL, Institute of Neurology, London, United Kingdom)
Fig. 1. TMS representation of the FDI in human (A) and monkey (B). Blue dots represent stimulation sites, the black dot the center of gravity. Colors indicate average MEP amplitudes from maximum (red; A: 1.85 mV, B: 1.22 mV) to minimum (blue; A: 0.01 mV, B: 0.03 mV).
Results: TMS Mapping sessions took about 80–90 min in each subject with a pulse interval of 8 s. Preparations lasted about 20 min. A closely spaced TMS representation of FDI could be identified in each subject within the precentral gyrus. The shape of the representation area resembled ovals with a mean maximum MEP amplitude of 1.35 mV (SD: 0.52). Mean stereotaxic coordinates of the centers of gravity were ( 36, 12, 67) in MNI152 space. In the animal experiment, the monkey adapted to the setup within 4 weeks. The preparation time for each session was about 10 min. Across all sessions muscle relaxation was present during 64% of the pulses. The pulse interval was 13.4 s. Four repetitions of a complete grid could be recorded in a single session of about 45 min duration. MEPs from contralateral FDI were elicited from a highly defined elliptical area (1 1.5 cm) within the precentral gyrus. Conclusion: Due to the combination of fast high-precision coil positioning and online head tracking, robot-assisted and imageguided TMS is exquisitely suited to perform randomized TMS mappings in the human with acceptable preparation times. In addition, this method allows for precise TMS mapping of the considerably smaller rhesus brain where high-precision coil positioning with a high inter-session reliability is required for multiple session mappings with grid sizes in the millimeter scale.
Fig. 1. doi:10.1016/j.clinph.2013.04.310
P 234. Transcranial direct current stimulation and Alzheimer’s disease—E. Khedr a, N. Foly El Gamal a, N. Abo El-Fetoh a, H. Khalifa a, A. Karim b, J. Rothwell c (a Assiut University Faculty of
Objective: This study was done to compare the effect of anodal, cathodal or sham transcranial direct current stimulation (tDCS) applied over the left dorsolateral prefrontal cortex (DLPFC) on cognitive function in patients with Alzheimer disease (AD). Material and methods: 34 AD patients with mild to moderate disease were randomly classified into three groups. The first group received anodal tDCS and 2nd group received cathodal tDCS and the 3rd group received sham tDCS stimulation over the left DLPFC, daily for 10 days (2 mA for 25 min every weekday for 2 weeks). Minimental State Examination (MMSE) and the verbal and performance scores of the Wechsler Adult Intelligent Scale (WAIS) were assessed before, after the 10 sessions, and then after 1, and 2 months later. Results: There were no significant differences between groups in any of the demographic, clinical data or the rating scales at baseline. A two factor ANOVA with GROUP (anodal, cathodal, sham) and TIME (before, after, 1, 2 months) as main factors showed a significant GROUP TIME interaction for the MMSE (df = 3,2, F = 3.2, p = 0.02) and a borderline significant effect for performance IQ (df = 3,2, F = XX, p = 0.044) but not verbal IQ. Post hoc paired comparisons of the groups showed that both anodal and cathodal TDCS improved MMSE by approx. 3 points versus sham. Only cathodal TDCS improved the performance IQ (by approx. 4 points). Conclusion: These results suggest that 10 daily sessions of either cathodal or anodal tDCS over the DLPFC can produce a sustained improvement in MMSE for at least 2 months in AD. There was a small effect of cathodal TDCS on performance IQ. doi:10.1016/j.clinph.2013.04.311
P 235. Focal EEG effects of High Definition tDCS (HD-tDCS) detected by EEG photic driving—V.V. Lazarev a, T. Tamborino a, M. Bikson b, M.L. Ferreira a, L. deAzevedo a, E.M. Caparelli-Dáquer c (a Fernandes Figueira Inst., FIOCRUZ, Rio de Janeiro, Brazil, b The City College of New York of CUNY, Department of Biomedical Engineering, New York, United Kingdom, c UERJ, Dpt. Ciências Fisiológicas, Rio de Janeiro, Brazil) HD-tDCS using a 4 1-ring configuration has been proposed as an alternative to conventional tDCS, capable to restrict effective current to an area within the ring perimeter. Previously we observed that HD-tDCS stimulation achieves changes in TMS-evoked motor responses comparable to conventional tDCS. In order to investigate focality predicted by computational models, here we used EEG to detect neuronal changes both inside and outside stimulated region. On 15 normal subjects (5 males, 21–57 years), an EEG cap with special electrode holders arranged according to the 4 1-ring configuration was placed with the central electrode holder over central area of the left hemisphere (C3). The peripheral holders were spaced 5 cm radially around the central holder at the corners of a square. Monopolar EEG (linked earlobes reference, eyes closed) was recorded inside stimulation area in the central 4 1 (anode-AnC3), post-central (medial cathode-Ct-C3p), pre-central (between the anode and two anterior cathodes-Int-C3a) positions, outside the stimulation area in the left occipital lead (O1) and at the homologous right hemisphere points (C4a, C4, C4p and O2). EEG recordings were performed during intermittent photic stimulation (IPS) of fixed frequencies 3, 5, 10 and 21 Hz with 30s intervals between stimulation runs as well as during 3 min resting states before (1st) and after (2nd background) IPS sessions. After the initial EEG recording of 9.5– 10 min duration, stimulation was delivered through a battery-driven
Society Proceedings / Clinical Neurophysiology 124 (2013) e39–e187
Medicine, Departments of Neuropsychiatry, Assiut, Egypt, b Assiut University Faculty of Medicine, Assiut, Egypt, c UCL, Institute of Neurology, London, United Kingdom)
Fig. 1. TMS representation of the FDI in human (A) and monkey (B). Blue dots represent stimulation sites, the black dot the center of gravity. Colors indicate average MEP amplitudes from maximum (red; A: 1.85 mV, B: 1.22 mV) to minimum (blue; A: 0.01 mV, B: 0.03 mV).
Results: TMS Mapping sessions took about 80–90 min in each subject with a pulse interval of 8 s. Preparations lasted about 20 min. A closely spaced TMS representation of FDI could be identified in each subject within the precentral gyrus. The shape of the representation area resembled ovals with a mean maximum MEP amplitude of 1.35 mV (SD: 0.52). Mean stereotaxic coordinates of the centers of gravity were ( 36, 12, 67) in MNI152 space. In the animal experiment, the monkey adapted to the setup within 4 weeks. The preparation time for each session was about 10 min. Across all sessions muscle relaxation was present during 64% of the pulses. The pulse interval was 13.4 s. Four repetitions of a complete grid could be recorded in a single session of about 45 min duration. MEPs from contralateral FDI were elicited from a highly defined elliptical area (1 1.5 cm) within the precentral gyrus. Conclusion: Due to the combination of fast high-precision coil positioning and online head tracking, robot-assisted and imageguided TMS is exquisitely suited to perform randomized TMS mappings in the human with acceptable preparation times. In addition, this method allows for precise TMS mapping of the considerably smaller rhesus brain where high-precision coil positioning with a high inter-session reliability is required for multiple session mappings with grid sizes in the millimeter scale.
Fig. 1. doi:10.1016/j.clinph.2013.04.310
P 234. Transcranial direct current stimulation and Alzheimer’s disease—E. Khedr a, N. Foly El Gamal a, N. Abo El-Fetoh a, H. Khalifa a, A. Karim b, J. Rothwell c (a Assiut University Faculty of
Objective: This study was done to compare the effect of anodal, cathodal or sham transcranial direct current stimulation (tDCS) applied over the left dorsolateral prefrontal cortex (DLPFC) on cognitive function in patients with Alzheimer disease (AD). Material and methods: 34 AD patients with mild to moderate disease were randomly classified into three groups. The first group received anodal tDCS and 2nd group received cathodal tDCS and the 3rd group received sham tDCS stimulation over the left DLPFC, daily for 10 days (2 mA for 25 min every weekday for 2 weeks). Minimental State Examination (MMSE) and the verbal and performance scores of the Wechsler Adult Intelligent Scale (WAIS) were assessed before, after the 10 sessions, and then after 1, and 2 months later. Results: There were no significant differences between groups in any of the demographic, clinical data or the rating scales at baseline. A two factor ANOVA with GROUP (anodal, cathodal, sham) and TIME (before, after, 1, 2 months) as main factors showed a significant GROUP TIME interaction for the MMSE (df = 3,2, F = 3.2, p = 0.02) and a borderline significant effect for performance IQ (df = 3,2, F = XX, p = 0.044) but not verbal IQ. Post hoc paired comparisons of the groups showed that both anodal and cathodal TDCS improved MMSE by approx. 3 points versus sham. Only cathodal TDCS improved the performance IQ (by approx. 4 points). Conclusion: These results suggest that 10 daily sessions of either cathodal or anodal tDCS over the DLPFC can produce a sustained improvement in MMSE for at least 2 months in AD. There was a small effect of cathodal TDCS on performance IQ. doi:10.1016/j.clinph.2013.04.311
P 235. Focal EEG effects of High Definition tDCS (HD-tDCS) detected by EEG photic driving—V.V. Lazarev a, T. Tamborino a, M. Bikson b, M.L. Ferreira a, L. deAzevedo a, E.M. Caparelli-Dáquer c (a Fernandes Figueira Inst., FIOCRUZ, Rio de Janeiro, Brazil, b The City College of New York of CUNY, Department of Biomedical Engineering, New York, United Kingdom, c UERJ, Dpt. Ciências Fisiológicas, Rio de Janeiro, Brazil) HD-tDCS using a 4 1-ring configuration has been proposed as an alternative to conventional tDCS, capable to restrict effective current to an area within the ring perimeter. Previously we observed that HD-tDCS stimulation achieves changes in TMS-evoked motor responses comparable to conventional tDCS. In order to investigate focality predicted by computational models, here we used EEG to detect neuronal changes both inside and outside stimulated region. On 15 normal subjects (5 males, 21–57 years), an EEG cap with special electrode holders arranged according to the 4 1-ring configuration was placed with the central electrode holder over central area of the left hemisphere (C3). The peripheral holders were spaced 5 cm radially around the central holder at the corners of a square. Monopolar EEG (linked earlobes reference, eyes closed) was recorded inside stimulation area in the central 4 1 (anode-AnC3), post-central (medial cathode-Ct-C3p), pre-central (between the anode and two anterior cathodes-Int-C3a) positions, outside the stimulation area in the left occipital lead (O1) and at the homologous right hemisphere points (C4a, C4, C4p and O2). EEG recordings were performed during intermittent photic stimulation (IPS) of fixed frequencies 3, 5, 10 and 21 Hz with 30s intervals between stimulation runs as well as during 3 min resting states before (1st) and after (2nd background) IPS sessions. After the initial EEG recording of 9.5– 10 min duration, stimulation was delivered through a battery-driven