Neural oscillation during working memory in left temporal lobe epilepsy

Abstract

Objective To summarize the characteristics of neural oscillation during the working memory maintenance in patients with left temporal lobe epilepsy (LTLE), and to explore the changes of neural oscillations in working memory disorders. Methods A total of 21 patients with LTLE (LTLE group) admitted to Tianjin Medical University General Hospital from September 2017 to May 2021 and 35 healthy controls (control group) with matched gender, age, education and cognitive function were enrolled. The visual working memory test was performed, response time and accuracy were recorded. Thirty-four channels of EEG signals were collected to calculate the power spectral density (PSD) of each frequency band during working memory maintenance. The PSD and spatial distribution of dominant frequency bands during working memory maintenance were compared between 2 groups. Results Compared with the control group, LTLE group had longer response time (t = 3.597, P = 0.001) and lower accuracy (t = 3.770, P = 0.001). θ frequency band was the dominant band during working memory maintenance, and the PSD of θ frequency band was mainly concentrated in the frontal region, especially the Fz channel of frontal midline. Compared with the control group, the PWM of θ frequency band of the whole brain (t = 2.600, P = 0.012), frontal region (t = 2.252, P = 0.029) and Fz channel (t = 2.496, P = 0.029) in LTLE group decreased. Conclusions LTLE patients with working memory disorders, and decreased θ oscillation during working memory may be a sensitive indicator of working memory disorders in patients with temporal lobe epilepsy.

Keywords

• epilepsy temporal lobe
• memory short-term;
• theta rhythm
• electroencephalography