EEG signatures of psychiatric and mental illness

Schizophrenia is a mental disorder which is characterised by a combination of symptoms including paranoid delusions, visual and auditory hallucinations, disorganized thoughts and language, apathy and social dysfunction. There are many hypotheses about the factors that lead to this illness such as genetic predisposition, neurochemical deficiency and structural abnormalities of the brain. Currently there are no diagnostic tools that can categorically identify the disorder and the diagnosis is established mainly after the manifestation of the symptoms. Many studies have been conducted in order to determine the criteria of biological markers that can be utilized to predict the onset of the illness. A possible endophenotype that is proving to be reliable is the Mismatch Negativity (MMN). The MMN is an acoustic event related potential (ERP) which is a memory based process generated automatically by the neurons as a response to the occurrence of changes in the auditory stimulus. This phenomenon occurs mainly in the primary auditory cortex, in the superior temporal gyrus and in the inferior frontal cortex. The purpose of this study is to investigate further the time-frequency components present in each deviant generated by the MMN and to examine the suitability of a single channel dry-electrode device as a substitute for the normal laboratory based procedure of conducting electroencephalography (EEG). This approach is being considered due to the difficulty of performing lengthy and uncomfortable multi-channel EEG on psychiatric patients. For this purpose a commercially available single channel dry sensor system from NeuroSky will be compared with a 64 channel Neuroscan Synamp2 system, using a previously developed MMN protocol. Data will be collected from the same scalp location using both systems and output measures such as ERP amplitude and latency will be quantitatively compared to assess the accuracy and sensitivity of the device for use in clinical research.Schizophrenia is a mental disorder which is characterised by a combination of symptoms including paranoid delusions, visual and auditory hallucinations, disorganized thoughts and language, apathy and social dysfunction. There are many hypotheses about the factors that lead to this illness such as genetic predisposition, neurochemical deficiency and structural abnormalities of the brain. Currently there are no diagnostic tools that can categorically identify the disorder and the diagnosis is established mainly after the manifestation of the symptoms. Many studies have been conducted in order to determine the criteria of biological markers that can be utilized to predict the onset of the illness. A possible endophenotype that is proving to be reliable is the Mismatch Negativity (MMN). The MMN is an acoustic event related potential (ERP) which is a memory based process generated automatically by the neurons as a response to the occurrence of changes in the auditory stimulus. This phenomenon occurs mainly in the primary auditory cortex, in the superior temporal gyrus and in the inferior frontal cortex. The purpose of this study is to investigate further the time-frequency components present in each deviant generated by the MMN and to examine the suitability of a single channel dry-electrode device as a substitute for the normal laboratory based procedure of conducting electroencephalography (EEG). This approach is being considered due to the difficulty of performing lengthy and uncomfortable multi-channel EEG on psychiatric patients. For this purpose a commercially available single channel dry sensor system from NeuroSky will be compared with a 64 channel Neuroscan Synamp2 system, using a previously developed MMN protocol. Data will be collected from the same scalp location using both systems and output measures such as ERP amplitude and latency will be quantitatively compared to assess the accuracy and sensitivity of the device for use in clinical research