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Abstract
Objective Early biomarkers for dementia with Lewy bodies (DLB) are lacking. To determine whether EEG differentiates the prodromal phase of DLB from other causes of mild cognitive impairment (MCI) and whether EEG is predictive for time to conversion from MCI to DLB, we compared EEGs and clinical follow-up of patients with MCI due to DLB with those of patients with MCI due to Alzheimer disease (MCI-AD).
Methods We compared 37 patients with MCI who developed DLB during follow-up or had an abnormal 123I-PF-CIT SPECT scan (MCI-DLB) with 67 age-matched patients with MCI-AD. EEGs were assessed visually with a score of increasing abnormality (range 1–5). We performed fast Fourier transform to analyze the power spectrum. With survival analyses, EEG characteristics were related to time to progression to dementia.
Results The visual EEG score was higher in MCI-DLB (score >2 in 60%) compared to MCI-AD (score >2 in 8%, p < 0.001). We found frontal intermittent delta activity in 22% of MCI-DLB, not in MCI-AD. Patients with MCI-DLB had a lower peak frequency (7.5 [6.0–9.9] Hz vs 8.8 [6.8–10.2] in MCI-AD, p < 0.001) and more slow-wave activity. Several individual EEG measures showed good performance to discriminate MCI-DLB from MCI-AD (areas under the curve up to 0.94). In MCI-DLB, high visual EEG score, diffuse abnormalities, and low α2 power were related to time to progression to dementia (hazard ratios 4.1, 9.9, 5.1, respectively).
Conclusions Profound EEG abnormalities are already present in the prodromal stage of DLB and have diagnostic and prognostic value.
Classification of evidence This study provides Class III evidence that EEG abnormalities are more common in MCI-DLB than MCI-AD.
Glossary
- AD=
- Alzheimer disease;
- ADC=
- Amsterdam Dementia Cohort;
- AUC=
- area under the receiver operating characteristic curve;
- CI=
- confidence interval;
- DFV=
- dominant frequency variability;
- DLB=
- dementia with Lewy bodies;
- FIRDA=
- frontal intermittent rhythmic delta activity;
- IQR=
- interquartile range;
- MCI=
- mild cognitive impairment;
- MMSE=
- Mini-Mental State Examination;
- OR=
- odds ratio;
- PD=
- Parkinson disease;
- qEEG=
- quantitative EEG;
- RBD=
- REM sleep behavior disorder
Footnotes
Go to Neurology.org/N for full disclosures. Funding information and disclosures deemed relevant by the authors, if any, are provided at the end of the article.
Class of Evidence: NPub.org/coe
CME Course: NPub.org/cmelist
- Received July 18, 2019.
- Accepted in final form January 27, 2020.
- © 2020 American Academy of Neurology
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