P09-F Anterior EEG slowing in Dementia with Lewy Bodies: A multicenter European cohort study

Abstract

Background EEG slowing with pre-alpha dominant frequency in posterior derivations is a supportive biomarker for Dementia with Lewy Bodies diagnosis, with high predictive value for the differential diagnosis with Alzheimer’s Disease. The appearance of a pre-alpha rhythm is considered to be linked to a dysfunctional thalamo-cortical connection. We hypothesize that the intra-subject evaluation would give information on possible different involvement of anterior and posterior cortical areas in Dementia with Lewy Bodies. Objectives Our aim was to analyse the anterior-posterior scalp distribution of dominant frequencies with an intra-subject evaluation in a dementia with Lewy bodies patient group. Methods We quantitatively analyzed EEGs of 122 patients from 5 Centers of the European dementia with Lewy bodies Consortium. EEG spectra values, divided into delta, theta, pre-alpha, alpha frequency bands were described by dominant frequency, dominant frequency variability, frequency prevalence. Results Dominant frequency in anterior derivations was lower than in posterior derivations (p = 2 · 10–4). Dominant frequency variability, frequency prevalence in delta and theta was higher in anterior derivations (3 · 10–7; 1 · 10–16; 1 · 10–5). As a consequence, frequency prevalence in pre-alpha and alpha was lower in anterior than posterior derivations (4 · 10–3; 1 · 10–7), due to the prevalence of delta/theta in anterior derivations. In 11% of patients, pre-alpha was dominant in anterior leads while alpha rhythm was still dominant in posterior derivations. Conclusions EEG slowing was more severe in anterior derivations. A future longitudinal study should address the possibility that the anterior EEG abnormalities appear earlier in the disease course.