aIstanbul Medipol University, Faculty of Medicine, Department of Biophysics, Istanbul, Turkey
bIstanbul Medipol University, REMER, Clinical Electrophysiology, Neuroimaging and Neuromodulation Laboratory, Istanbul, Turkey cIstanbul Kultur University, Brain Dynamics Cognition and Complex Systems Research Center, Istanbul, Turkey
dDokuz Eylul University Department of Neurology, Izmir, Turkey Background: In the last decade research on delta oscillatory responses invaded the literature. One of the first research on this area showed that delta responses increase upon cognitive load (Başar and Stampfer 1985). After this preliminary result, many researchers have shown that delta responses are related to attention, perception, decision making and working memory processes. Our group and other groups in the literature indicated that the delta responses in different patient groups were decreased during cognitive load in comparison to healthy controls. In a recent review we have described that decrease of delta responses could be a candidate of a general electrophysiological biomarker for neuropsy-chiatric disorders (Güntekin and Başar 2015). Delta responses were decreased in Alzheimer’s disease, in Mild Cognitive impairment (MCI) in bipolar disorder patients and as well as in schizophrenia patients during cognitive load in comparison to healthy controls. In the present study we analyze the delta responses in Parkinson’s disease with and without cognitive deficits.
Method: 27 patients with Parkinson’s disease (12 of them were without any cognitive deficits; 15 of them were with MCI or dementia) and 17 age- and education-matched healthy-elderly controls (HC) participated in the study. EEG was recorded at 32 electrode sites upon application of auditory oddball paradigm. The maximum amplitudes of each subject’s delta response (0.5–3.5 Hz) upon application of target stimulation were measured for each electrode. Repeated measures ANOVA was used for statistical analysis.
Results: Statistically significant results were found between groups. Healthy controls had higher delta responses than patients with Parkinson disease with and without cognitive deficits (pb0.05, for each comparison). Patients with Parkinson’s disease had %27-35 lower delta responses than healthy controls especially over frontal areas.
Conclusion: The results of the present study once more strengthen the hypothesis that decrease of delta oscillatory responses could be candidate of a general electrophysiological biomarker for neuropsychi-atric disorders. The search on specific biomarkers for each specific neuropsychiatric disease should include analysis of all frequency bands with applying several methods of EEG-brain dynamics.
doi:10.1016/j.ijpsycho.2016.07.195
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Oscillatory dynamics of the oddball response in children with attention deficit hyperactivity disorder
Sirel Karakasa, Elvin Doğutepea, Bakar Erdoğanb
aDogus University, Estanbul, Turkey | Neurometrika Medical Technologies LLC, Ankara, Turkey
bUfuk University, Ankara, Turkey
Oddball paradigm triggers the P300 component. The component is predominantly formed by the delta oscillation and is responsible from attention and working memory (context updating), to which attentional processing is closely linked. Attention deficit hyperactiv-ity disorder (ADHD) is customarily approached using pharmacother-apy while other techniques such as biofeedback uses training
involving oscillatory components. The present study compares the oscillatory activity in the oddball response of the ADHD and control groups under an experimentally produced attentional state. The sample included 6-12-year-old boys with ADHD (combined subtype: 49 cases, attention deficit subtype= 17 cases), and age-matched healthy controls (n= 40). Children werefirst referrals and were not on pharmacotherapy. Exclusion criteria were neurological and/or psychiatric comorbidity other than ADHD and intelligence level outside the 85-129 IQ range. In the auditory oddball paradigm, the 25 % deviants were 1000 Hz and the 75% standards were 2500 Hz (ISI= 1500 msec). Particiants were asked to count the deviants and report them at the end of the recording session. Attention was maintained using the stimulus omission paradigm. The paradigm included a series of equally-spaced (ISI= 1500 msec) visual stimuli (circles) every fourth of which was omitted. The participants were asked to attend to the consecutive stimuli and indicate the time point at which the 5th stimulus should occur by a button-press response. The oddball and stimulus omission paradigms were given in alternating order. The difference between the response accuracy rate of the control and clinical groups were not significant. The delta component was extracted in the time-plane and time-frequency planes. Digitally filtered delta and theta oscillations were not significantly different in amplitude and latency between the clinical and control groups. In the time-frequency plane, the configuration of responses to the standard stimuli were not significantly different between the groups. The deviant response of the control group was characterized by a frontally recorded theta component followed by two delta components. Otherwise, time-frequency layout of the oscillatory components were similar between the groups. In ADHD, P300 latency is longer and amplitude generally higher. When cases were kept at an enduring attentional state, delta and theta oscillatory responses that contribute to the morphology of P300 became similar. These results show that the ADHD symptoms may temporarily subside upon appropriate cognitive manipulations. The stability and ecological validity of this“improvement”, however, needs to be studied in future reserach.
doi:10.1016/j.ijpsycho.2016.07.196
104
ERP and motor changes following therapy in the Gilles de la Tourette Syndrome
Marc Lavoie, Kieron O'Connor, Julie leclerc, Pierre Blanchet, Simon Morand-Beaulieu
Institut Universitaire en Sante Mentale de Montreal Laboratoire de Psychophysiologie Cognitive et Sociale, Montreal, Canada
Departement de Psychiatrie et de Neurosciences Universite de Montreal, Montreal, Canada
Background: Tic disorders, such as the Gilles de la Tourette syndrome and persistent tic disorder, are neurodevelopmental move-ment disorders involving impaired motor control such as repetitive unwanted muscular contractions in one or more parts of the body. Our earlierfindings showed that, following cognitive-behavioral therapy (CBT), a normalization of specific types of brain activity was present following an improvement in symptoms. A CBT, with a particular emphasis on the psychophysiology of tic expression and sensorimotor activation, can reduce the frequency and intensity of tics. However, its impact on motor activation and inhibition is not fully understood.
Objective: Our research aim to investigate the phenomenon of brain plasticity in the context of a psychological intervention in tic disorders. The current talk will present the broad lines of the
