Examining neurophysiological markers of apathy and processing speed in late premanifest and early-stage manifest Huntington’s disease

Abstract

Sensitive biological markers of non-motor symptoms in Huntingtons disease (HD) are essential for the development and assessment of novel treatments. To this end we used resting state EEG to examine differences in oscillatory activity (analysing the isolated periodic as well as the complete EEG signal) and functional connectivity in 22 people with HD and 20 neurotypical controls. We then assessed the correlations between these neurophysiological markers and clinical measures of apathy and cognitive functioning. Significantly lower theta and greater delta resting state power was seen in the HD group, as well as significantly greater delta connectivity. There was a significant positive correlation between theta power and processing speed, however there were no associations between the neurophysiological and apathy measures. We speculate that these changes in oscillatory power and connectivity reflect ongoing, frontally concentrated degenerative and compensatory processes associated with HD. Our findings support the potential utility of quantitative EEG as a proximate marker for non-motor symptoms in HD.

Brain Segregation and Integration Relate to Word-Finding Abilities in Older and Younger Adults

“…Research has also indicated that individuals with Huntington's disease exhibit greater delta-band connectivity, which could indicate either pathological or compensatory changes in brain function (Davis et al, 2022). That is, brain activity may be synchronising to a less functional frequency range (here, delta), perhaps as a pathology-related compensatory process, or perhaps reflecting the brain's inability to inhibit this (potentially less functional)…”

“…Less-modular brain networks at rest may allow for a fast reorganisation of the brain network and the direction of attention to the task at hand. Alternatively, the finding in alpha but not delta frequency band modularity might reflect a compensatory mechanism whereby brain activity synchronises within a less functionally specific frequency band (Davis et al, 2022).…”

Medial prefrontal transcranial alternating current stimulation for apathy in Huntington’s disease

“…This paper presents the results of tACS effects on task-related EEG and behavioural data. Please note that we have previously analysed the baseline differences between our participants with HD (n = 22) and neurotypical controls (n = 20) to explore the relationship between neurophysiological markers and clinical measures of apathy and cognition (Davis, Hill, Fitzgerald, Bailey, et al 2022).…”