TY - JOUR

T1 - Investigation of sleep spindle activity and morphology as predictors of neurocognitive functioning in medicated patients with schizophrenia

AU - Baandrup, Lone

AU - Christensen, Julie A E

AU - Fagerlund, Birgitte

AU - Jennum, Poul

N1 - © 2018 European Sleep Research Society.

PY - 2019

Y1 - 2019

N2 - Neurocognitive impairment is a trait marker of schizophrenia, but no effective treatment has yet been identified. Sleep spindle deficits have been associated with diminished sleep-dependent memory learning. We examined whether this link could be extended into various cognitive domains by investigating the association of a neurocognitive test battery (the Brief Assessment of Cognition in Schizophrenia) with sleep spindle activity and morphology. We examined 37 outpatients diagnosed with schizophrenia and medicated with both antipsychotics and benzodiazepines. Participants underwent 1 night polysomnography and test of neurocognitive functioning. We identified and analysed sleep spindles in all non-rapid eye movement sleep and in non-rapid eye movement sleep stage 2 in a central electroencephalography channel using an automatic sleep spindle detector previously validated. Slow sleep spindle density was computed from a frontal electroencephalography channel as well. We found no association between cognitive functioning and sleep spindle density or sleep spindle morphology for spindles in non-rapid eye movement sleep when controlling for gender, age, symptom severity, and daily dose of antipsychotics and benzodiazepines. For spindles in non-rapid eye movement sleep stage 2, we found that motor speed was associated with frontal slow sleep spindle density. We conclude that frontal slow spindle density might predict motor speed in medicated patients with schizophrenia, but that no other sleep spindle activity or sleep spindle morphology measures were predictors of neurocognitive functioning.

AB - Neurocognitive impairment is a trait marker of schizophrenia, but no effective treatment has yet been identified. Sleep spindle deficits have been associated with diminished sleep-dependent memory learning. We examined whether this link could be extended into various cognitive domains by investigating the association of a neurocognitive test battery (the Brief Assessment of Cognition in Schizophrenia) with sleep spindle activity and morphology. We examined 37 outpatients diagnosed with schizophrenia and medicated with both antipsychotics and benzodiazepines. Participants underwent 1 night polysomnography and test of neurocognitive functioning. We identified and analysed sleep spindles in all non-rapid eye movement sleep and in non-rapid eye movement sleep stage 2 in a central electroencephalography channel using an automatic sleep spindle detector previously validated. Slow sleep spindle density was computed from a frontal electroencephalography channel as well. We found no association between cognitive functioning and sleep spindle density or sleep spindle morphology for spindles in non-rapid eye movement sleep when controlling for gender, age, symptom severity, and daily dose of antipsychotics and benzodiazepines. For spindles in non-rapid eye movement sleep stage 2, we found that motor speed was associated with frontal slow sleep spindle density. We conclude that frontal slow spindle density might predict motor speed in medicated patients with schizophrenia, but that no other sleep spindle activity or sleep spindle morphology measures were predictors of neurocognitive functioning.

KW - anxiolytics

KW - cognition

KW - psychosis

KW - sedatives

KW - sleep microstructure

UR - http://www.scopus.com/inward/record.url?scp=85042558654&partnerID=8YFLogxK

U2 - 10.1111/jsr.12672

DO - 10.1111/jsr.12672

M3 - Journal article

VL - 28

SP - e12672

JO - Journal of Sleep Research

JF - Journal of Sleep Research

SN - 1365-2869

IS - 1

M1 - e12672

ER -