Too little or too much nocturnal movements in Parkinson's disease: A practical guide to managing the unseen

Abstract

Nocturnal and sleep-related motor disorders in people with Parkinson's disease (PD) have a wide spectrum of manifestations and present a complex clinical picture. Problems can arise due to impaired movement ability (hypokinesias), e.g. nocturnal hypokinesia or early-morning akinesia, or to excessive movement (hyperkinesias), e.g. end-of-the-day dyskinesia, parasomnias, periodic limb movement during sleep and restless legs syndrome. These disorders can have a significant negative impact on the sleep, daytime functional ability, and overall quality of life of individuals with PD and their carers. The debilitating motor issues are often accompanied by a combination of non-motor symptoms, including pain and cramping, which add to the overall burden. Importantly, nocturnal motor disorders encompass a broader timeline than just the period of sleep, often starting in the evening, as well as occurring throughout the night and on awakening, and are not just limited to problems of insomnia or sleep fragmentation. Diagnosis can be challenging as, in many cases, the 'gold standard' assessment method is video polysomnography, which may not be available in all settings. Various validated questionnaires are available to support evaluation, and alternative approaches, using wearable sensors and digital technology, are now being developed to facilitate early diagnosis and monitoring. This review sets out the parameters of what can be considered normal nocturnal movement and describes the clinical manifestations, usual clinical or objective assessment methods, and evidence for optimal management strategies for the common nocturnal motor disorders that neurologists will encounter in people with PD in their clinical practice.

Keywords: Evening dyskinesia; Nocturnal hypokinesia; Nocturnal movement disorders; Parkinson’s disease; Periodic limb movement disorders; Sleep-related movement disorders.

Fig. 1

The spectrum of nocturnal motor disorders ranging from those due to hypokinetic movements (left) to those due to hyperkinetic movements (right). ALMA, alternating legs muscle activation; EFM, excessive fragmentary myoclonus; HFT, hypnagogic foot tremor; HFLM high-frequency leg movements; PD, Parkinson’s disease; PLMS, periodic limb movements during sleep; RBD, REM sleep behaviour disorder; REM, rapid eye movement; RFM, rhythmic feet movements; RLS, restless legs syndrome.

Fig. 2

Spectrum of nocturnal hypokinesia and associated manifestations. Individual arrows reflect the period during the night in which the disorder becomes symptomatic.