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Disturbed sleep in Parkinson's disease: anatomical and pathological correlates

Authors


Correspondence: Michail E. Kalaitzakis, Neuropathology Unit, Division of Brain Sciences, Department of Medicine, Imperial College London, Charing Cross Campus, St Dunstan's Road, London W6 8RP, UK. Tel: +44 203 311 7275; Fax: +44 208 846 7794; E-mail: michail.kalaitzakis03@imperial.ac.uk

Abstract

Aims

Abnormal sleep is a common feature of Parkinson's disease (PD) and prodromal disorders of sleep are frequent (e.g. restless legs syndrome and rapid eye movement sleep behaviour disorder). However, the exact pathological basis of disturbed sleep remains as yet undefined.

Methods

To investigate this further, 32 PD cases were stratified into three groups: (1) PD with disturbed sleep, PD(S); (2) PD with dementia (PDD) and disturbed sleep, PDD(S); and (3) PD without disturbed sleep, PD(nS). The extent of α-synuclein (αSyn) and Alzheimer disease (AD)-type pathology [amyloid β peptide (Aβ) and tau] was assessed in 15 regions of the PD brain.

Results

The results demonstrate a significant association between disturbed sleep in PD and αSyn pathology in specific brainstem [locus coeruleus (P = 0.006) and raphe nuclei (P = 0.02)], hypothalamic [paramammillary nuclei (P = 0.04) and posterior nucleus (P = 0.02)], subcortical/limbic [amygdala (P = 0.03), thalamus (P = 0.01)] and cortical [entorhinal cortex (P = 0.01)] regions. A statistically significant increase of tau pathology was observed in the amygdala (P = 0.03), CA2 sector of the hippocampus (P = 0.01) and entorhinal cortex (P = 0.04) in PD cases with disturbed sleep.

Conclusions

Pathological changes in these structures, residing in the brain circuitry relating to sleep physiology, strongly predict the presence of sleep disturbances in PD.

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