Cortical oscillations that underlie working memory are altered in adults with cerebral palsy

•Adults with cerebral palsy (CP) and controls completed a working memory task during MEG.•Prefrontal alpha–beta cortical oscillations were weaker in adults with CP during encoding.•Weaker alpha–beta oscillation may be the neurophysiological nexus of the reduced cognition seen in adults with CP. This investigation used magnetoencephalography (MEG) to identify the neurophysiological mechanisms contributing to the altered cognition seen in adults with cerebral palsy (CP). Adults with CP (GMFCS levels I-IV) and demographically-matched controls completed a Sternberg-type working memory task during MEG. Secondarily, they completed the National Institutes of Health (NIH) cognitive toolbox. Beamforming was used to image the significant MEG oscillatory responses and the resulting images were examined using statistical parametric mapping to identify cortical activity that differed between groups. Both groups had a left-lateralized decrease in alpha–beta (11–16 Hz) power across the occipital, temporal, and prefrontal cortices during encoding, as well as an increase in alpha (9–13 Hz) power across the occipital cortices during maintenance. The strength of alpha–beta oscillations in the prefrontal cortices were weaker in those with CP during encoding. Weaker alpha–beta oscillation within the prefrontal cortex was associated with poorer performance on the NIH toolbox and a higher GMFCS level. Alpha-beta aberrations may impact the basic encoding of information in adults with CP, which impacts their overall cognition. Altered alpha–beta oscillation might be connected with gross motor function. This experimental work highlights the aberrant alpha–beta during encoding as possible neurophysiological mechanism of the cognitive deficiencies.