Longitudinal EEG Changes Correlate with Cognitive Measure Deterioration in Parkinson's Disease

Abstract

Background: QEEG could provide physiological biomarkers for changes over time in Parkinson's disease (PD) cognitive decline if they track with longitudinal neuropsychological performance. Objective: Our aim was to correlate longitudinal changes in frequency domain quantitative electroencephalography (QEEG) measures with change in neuropsychological performance testing in PD. Methods: 71 PD subjects, not demented at baseline, were studied from the Arizona Study of Aging and Neurodegenerative Disorders cohort. Baseline and follow-up digital EEG from PD subjects were analyzed for QEEG measures of background rhythm frequency and global relative power in delta (2.5-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), and beta (13-30 Hz) bands. Baseline and subsequent evaluation included Mini Mental Status Examination and five other neuropsychological tests that load on cognitive domains known to decline in PD. Pearson coefficient was used to assess correlations. Multiple linear regression modeling was used to assess the effect of variable combinations of QEEG and other measures, including age and PD duration. Results: Changes in delta bandpower showed the highest and most consistent pattern of correlations with longitudinal changes in neuropsychological testing. The highest correlation was between delta bandpower increase and decline in the Rey Auditory-Verbal Learning Test (−0.59:p < 0.001). Delta bandpower was also increased in the incident dementia group compared to non-dementia at followup. Conclusions: 1) Longitudinal change in the QEEG frequency domain measure of delta bandpower correlated best with longitudinal neuropsychological performance change in PD; 2) These results constitute preliminary evidence that delta bandpower may be a suitable biomarker for evaluating PD cognitive deterioration longitudinally.

Differential spectral quantitative electroencephalography patterns between control and Parkinson's disease cohorts

“…For example, delta bandpower only shows significant changes between groups that show differences in cognitive performance. This is consistent with our recent finding that delta bandpower is associated with PD-D incidence [11]. As intrinsic cortical pathology is associated with PD-D, it may be that the intrinsic cortical pathology plays a role in producing delta bandpower [3].…”

“…characteristics are known to be abnormal in PD dementia [6][7][8][9][10][11][12]. Such measures have been proposed as biomarkers of PD cognitive decline [10,11]. Similar EEG changes have been observed in Alzheimer's disease and therefore should not be considered specific for PD [11].…”

“…Such measures have been proposed as biomarkers of PD cognitive decline [10,11]. Similar EEG changes have been observed in Alzheimer's disease and therefore should not be considered specific for PD [11]. Nevertheless, such changes could be successfully employed as a biomarker within PD groups.…”

Cognitive decline in Parkinson disease

“…The findings include associations between executive dysfunction 160 or Mini-Mental State Examination (MMSE) score 161 and spectral ratio (the ratio of fast to slow activity), between performance deficits in attention, executive function and memory and increased delta power 162 or decreased EEG median frequency 163 , and between clinical ratings of background EEG slowing and combined MMSE and clock drawing test scores 164 . An increase in low-frequency (delta and theta) EEG spectral power distinguishes PDD from PD and AD 165 .…”

Cortical phosphorylated α-Synuclein levels correlate with brain wave spectra in Parkinson's disease

“…Physiological changes in cortical activity have been established to correlate with PD cognitive decline. [8][9][10][11][12][13] The resting EEG is simple to acquire, requires minimal patient cooperation, and is not dependent on verbal or motor responses, which may be affected in PD. QEEG measures may be ideal biomarkers to complement neuropsychological testing with physiological corroboration for studying cognitive decline among patients with PD.…”