Sleep Disruption After Brain Injury Is Associated With Worse Motor Outcomes and Slower Functional Recovery

Useless. Describes a problem, OFFERS NO SOLUTION. The questions they are trying to answer have absolutely nothing to do with getting survivors recovered.

Sleep Disruption After Brain Injury Is Associated With Worse Motor Outcomes and Slower Functional Recovery

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Melanie K. Fleming, PhD, Tom Smejka, MSc, David Henderson Slater, MRCP, ...

First Published June 7, 2020 Research Article Find in PubMed

https://doi.org/10.1177/1545968320929669

Article information

Abstract

Background.
Sleep is important for consolidation of motor learning, but brain injury may affect sleep continuity and therefore rehabilitation outcomes.  
Objective.
This study aims to assess the relationship between sleep quality and motor recovery in brain injury patients receiving inpatient rehabilitation.  
Methods.
Fifty-nine patients with brain injury were recruited from 2 specialist inpatient rehabilitation units. Sleep quality was assessed (up to 3 times) objectively using actigraphy (7 nights) and subjectively using the Sleep Condition Indicator. Motor outcome assessments included Action Research Arm test (upper limb function), Fugl-Meyer Assessment (motor impairment), and the Rivermead Mobility Index. The Functional Independence Measure (FIM) was assessed at admission and discharge by the clinical team. Fifty-five age- and gender-matched healthy controls completed one assessment.  
Results.
Inpatients demonstrated lower self-reported sleep quality (P < .001) and more fragmented sleep (P < .001) than controls. For inpatients, sleep fragmentation explained significant additional variance in motor outcomes, over and above that explained by admission FIM score (P < .017), such that more disrupted sleep was associated with poorer motor outcomes. Using stepwise linear regression, sleep fragmentation was the only variable found to explain variance in rate of change in FIM (R²_adj = 0.12, P = .027), whereby more disrupted sleep was associated with slower recovery.
Conclusions.
Inpatients with brain injury demonstrate impaired sleep quality, and this is associated with poorer motor outcomes and slower functional recovery. Further investigation is needed to determine how sleep quality can be improved and whether this affects outcome.

Keywords sleep, brain injury, stroke, motor, recovery, functional independence

Introduction

Sleep disturbance is a common complaint after brain injury, including stroke, with a high proportion (30%-70%) of patients presenting with impaired subjective sleep quality and meeting the criteria for at least one sleep disorder.^1-4 Sleep disturbance could be resulting from direct damage to brain areas, or due to secondary effects such as being in the hospital environment, depression, anxiety or pain, and could potentially have an impact on rehabilitation through reduced engagement or impaired learning and consolidation.⁵
There is some evidence for improvements in sleep quality from the acute to the chronic stage of stroke^6,7; however, stroke survivors at the chronic stage continue to have impaired subjective and objective sleep quality and worse quality of life than controls.^8,9 Interestingly, the longer the time since stroke, the worse the perceived daytime sleepiness becomes.¹⁰ This suggests that sleep disturbance may be persistent throughout the rehabilitation period for some, and changes within this time frame in patients with different types of brain injuries are yet to be determined.
The link between sleep quality and function after stroke and brain injury is currently emerging. Siccoli et al¹¹ demonstrated a cross-sectional correlation between the National Institute for Health Stroke Scale (NIHSS) score and wake after sleep onset (WASO), in a small sample of acute stroke patients. A larger study¹² found a cross-sectional relationship between subjective sleep quality and the functional ambulation score after stroke but had no objective sleep measures. Similarly, Kalmbach et al¹³ found that patients with subjective difficulties initiating sleep had lower function at multiple time-points over the first 6 months of recovery from traumatic brain injury (TBI). Sleep variables, such as total sleep time, WASO and daytime napping, have also been shown to explain significant variance in Barthel Index (BI) score at the acute stage of stroke,^14,15 and the percentage of sleep stages I and rapid eye movement (REM) are negatively associated with NIHSS.¹⁶
However, there is little research to indicate whether sleep quality over the rehabilitation period correlates with outcome or change in function over time, and studies that are available are somewhat inconsistent in their findings. The presence of sleep-disordered breathing at the acute stage has been found to be associated with reduced modified Rankin scale (mRS) and BI at 6 weeks poststroke¹⁷ and other studies have demonstrated that stroke patients categorized with a “poor” functional outcome have a lower sleep efficiency, less REM sleep or a reduced REM sleep latency at the acute stage than those with a better outcome.^16,18,19 In contrast, Joa et al²⁰ found no difference in the change in NIHSS or BI between patients reporting sleep disturbance at 1 month poststroke and those reporting no disturbance. They did, however, find that the group reporting no sleep disturbance had a greater improvement in the Berg Balance Scale (BBS). This was particularly evident for the moderate-severe stroke patients compared with mild (on the basis of NIHSS score at 1 week poststroke), suggesting sleep may have a greater impact on functional recovery in those who have the most relearning to achieve. The studies by Iddagoda et al⁴ and Joa et al²⁰ used only subjective sleep measures and many of the studies have divided participants into groups based on outcome or the presence/absence of sleep disturbance, rather than examining both sleep quality and outcome as a continuum which may be more sensitive to differences across participants. Studies that did assess objective sleep quality as a continuum are mixed in their findings. Bakken et al¹⁵ found no correlation between sleep variables in the acute stage and BI at 6 months post stroke whereas Vock et al⁷ found that higher WASO or lower sleep efficiency at the acute stage post stroke was associated with worse outcome (mRS or BI score) at discharge. Similarly, Huang et al¹⁴ demonstrate that total sleep time correlates positively, and sleep latency correlates negatively, with the change in BI with rehabilitation.
As there is no clear consensus on the relationship between sleep quality measures and the rate of recovery with rehabilitation, and it is unclear how sleep quality changes over the course of rehabilitation, we sought to conduct a prospective assessment of sleep quality in neurological inpatients and explore the relationship with neurorehabilitation outcomes. We therefore assessed objective and subjective sleep quality at up to 3 time-points throughout the rehabilitation period and examined the relationship between sleep quality and motor and functional outcome measures. Specifically, we aimed to address the following questions(Why? Nothing for survivors here.):

1. Does sleep quality at a single time-point correlate with function/impairment at that time-point?
2. Does sleep quality change over the inpatient rehabilitation period?
3. Does objective sleep quality averaged over the inpatient rehabilitation period explain variance in motor outcomes over that explained by baseline function?
4. Does objective or subjective sleep quality averaged over the inpatient rehabilitation period explain variance in the rate of recovery in addition to covariates such as initial independence, age, and time since injury?