Interventions to improve memory in schizophrenia might need to both increase spindle density as well as boost spindle coordination with non-rapid eye movement (NREM) oscillations, according to research presented at SLEEP 2017, held June 3-7, 2017 in Boston, Massachusetts.
Researchers from the department of psychiatry at Massachusetts General Hospital in Boston had earlier conducted a small placebo-controlled pilot study to determine that eszopiclone increased spindles in schizophrenia. However, they also found that the drug had an insignificant effect on memory consolidation.
In order to further their study of eszopiclone’s effects on spindle activity and sleep-dependent memory consolidation, the researchers randomly assigned 55 participants – 26 chronic, medicated patients with schizophrenia and 29 healthy controls – to either placebo first or 3 mg of eszopiclone first conditions separated by 1 week. Both conditions included 2 consecutive nights of high-density electroencephalogram (EEG) polysomnography.
Patients in the placebo condition showed widespread reductions in spindle density that reached significance in a parietal cluster (P =.04). Eszopiclone increased spindle density across channels in both groups (P< .001) but more for patients than for controls in parietal regions (P =.03). While significant memory consolidation occurred in both placebo groups, eszopiclone did not increase in either group.
“While eszopiclone significantly increased spindles, and spindles correlated with memory, eszopiclone did not improve memory,” the researchers said. “This may reflect that memory consolidation relies not only on spindles, but also on their coordination with other NREM oscillations.”
Baran B, Demanuele C, Vuper TC, et al. The Effects of eszopiclone on sleep spindles and memory consolidation in schizophrenia: a double-blind randomized trial. Abstract 1113. Presented at: SLEEP 2017; June 3-7, 2017; Boston, Massachusetts.