Feeling of presence in dementia with Lewy bodies is related to reduced left frontoparietal metabolism

Nicolas Nicastro,Frederic Assal,Antoine F Eger,Valentina Garibotto

doi:10.1007/s11682-018-9997-7

Abstract

Feeling of presence (FOP) refers to the vivid sensation of a person’s presence near oneself and is common in Dementia with Lewy Bodies (DLB). Based on previous observations on epileptic subjects, we hypothesized that DLB subjects with FOP would harbour 18F-fluorodeoxyglucose PET hypometabolism in left parietal areas. 25 subjects (mean age 71.9 ± 6.7, disease duration at scan 1.7 ± 1.5 years) were included in the study, of whom nine (36%) experienced FOP. No significant between-group difference was observed regarding dopamine transporters striatal uptake (p = 0.64), daily dopaminergic treatment dosage (p = 0.88) and visual hallucinations (p = 0.83). Statistical parametric mapping showed that subjects with FOP had a significantly reduced glucose metabolism in several left frontoparietal areas (p < 0.001), including superior parietal lobule and precuneus. Interregional correlation analysis of these areas showed specific connectivity with right insula and putamen in the FOP subgroup and right orbitofrontal and superior frontal in subjects without FOP. This provides further evidence about the role of a left frontoparietal network and suggest a possible contribution of impaired orbitofrontal reality filtering associated with FOP.

Highlights

Dementia with Lewy bodies (DLB) is the second most common degenerative dementia after Alzheimer’s disease (AD), accounting for 15% of cases (Vann Jones and O'Brien 2014; Zaccai et al 2005)
We identified 25 subjects fulfilling McKeith diagnostic criteria of probable DLB for which both 18F-FDG PET and 123I-FP-CIT single photon emission computed tomography (SPECT) were performed according to the aforementioned criteria
MMSE score, presence of visual hallucinations and 123I-FP-CIT SPECT visual and semiquantitative assessments did not differ between Feeling of presence (FOP)+ and FOP- subjects

Summary

Introduction

Dementia with Lewy bodies (DLB) is the second most common degenerative dementia after Alzheimer’s disease (AD), accounting for 15% of cases (Vann Jones and O'Brien 2014; Zaccai et al 2005) Feeling of presence (FOP) refers to the vivid sensation that somebody is present near oneself in the absence of any sensory clue It has been described in various conditions such as schizophrenia (Koehler and Sauer 1984), epilepsy (Arzy et al 2006; Blanke et al 2003), Parkinson’s disease (Fenelon et al 2000), and DLB (Nagahama et al 2010). Right occipitotemporal hypometabolism has been described in subjects with visual hallucinations (Perneczky et al 2008)

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