Spatio-temporal Dynamics of EEG Microstates during Visuo-Spatial Working Memory Task as a Trait Marker for Patients with Schizophrenia

Poster Session B - Sunday, April 14, 2024, 8:00 – 10:00 am EDT, Sheraton Hall ABC

Madhavi Nayyar¹ (drmadhavinayyar@gmail.com), Sunaina Soni¹, Ratna Sharma¹, Suriya Prakash M¹, Prashant Tayade¹, Simran Kaur¹, Abhisek Sahoo¹; ¹All India Institute of Medical Sciences, New Delhi

OBJECTIVE: To study qEEG microstates and their cortical sources during Visio-Spatial Working Memory (VSWM) task in patients with schizophrenia as compared to healthy subjects. BACKGROUND: Spatio-temporal parameters of the quasi-stable EEG functional microstates and their intracranial generators can potentially be a state and trait marker for different cognitive and diseased states. Working memory deficits, a stable aspect of schizophrenia, tested by computer administered VSWM task with simultaneous dense array EEG acquisition to assess large scale brain networks can contribute to better diagnostic accuracy. METHODS: 30 patients diagnosed with schizophrenia (as per DSM-5 criteria) and 30 age-matched controls were administered questionnaires (Edinburgh Handedness Inventory, Hindi MMSE, SAPS, and SANS). Thereafter, 128 channel EEG, ECG, and GSR (Galvanic Skin Resistance) were recorded during eyes closed, eyes open, and VSWM task performance. Epoch wise data from each experimental condition was extracted and subjected to microstate analysis. Statistical analysis was done to compare temporal microstate parameters (Global explained variance, number of time frames, mean duration, time coverage, and segment count density) and cortical sources of each microstate map across the groups. RESULTS and CONCLUSIONS: Significantly lower accuracy and higher search time in VSWM task along with altered stress reactivity in patients with schizophrenia was noted. Temporal EEG microstates parameters during pre-re-encoding and pre-response period showed significant differences in patients with schizophrenia associated with hypoactivation in cortical areas subserving working memory domain, which could potentially be a trait marker for schizophrenia.

Topic Area: EXECUTIVE PROCESSES: Working memory