REM sleep and muscle atonia in brainstem stroke: A quantitative polysomnographic and lesion analysis study

Secondary RBD: Not just neurodegeneration

Rapid eye movement sleep behavior disorder is a parasomnia characterized by excessive muscle activity during rapid eye movement sleep (rapid eye movement sleep without atonia), along with dream enactment behavior. Isolated rapid eye movement sleep behavior disorder tends to occur in older males and is of concern due to the known link to Parkinson's disease and other synucleinopathies. When rapid eye movement sleep behavior disorder occurs in association with other neurological or general medical conditions, or resulting from the use of various substances, it is called secondary rapid eye movement sleep behavior disorder; the most common cause is neurodegenerative illness, specifically the synucleinopathies. Here, the focus will be on the subset of secondary rapid eye movement sleep behavior disorder in which there is no neurodegenerative disease.

Neural Control of REM Sleep and Motor Atonia: Current Perspectives

PURPOSE OF REVIEW

Since the formal discovery of rapid eye movement (REM) sleep in 1953, we have gained a vast amount of knowledge regarding the specific populations of neurons, their connections, and synaptic mechanisms regulating this stage of sleep and its accompanying features. This article discusses REM sleep circuits and their dysfunction, specifically emphasizing recent studies using conditional genetic tools.

RECENT FINDINGS

Sublaterodorsal nucleus (SLD) in the dorsolateral pons, especially the glutamatergic subpopulation in this region (SLDGlut), are shown to be indispensable for REM sleep. These neurons appear to be single REM generators in the rodent brain and may initiate and orchestrate all REM sleep events, including cortical and hippocampal activation and muscle atonia through distinct pathways. However, several cell groups in the brainstem and hypothalamus may influence SLDGlut neuron activity, thereby modulating REM sleep timing, amounts, and architecture. Damage to SLDGlut neurons or their projections involved in muscle atonia leads to REM behavior disorder, whereas the abnormal activation of this pathway during wakefulness may underlie cataplexy in narcolepsy. Despite some opposing views, it has become evident that SLDGlut neurons are the sole generators of REM sleep and its associated characteristics. Further research should prioritize a deeper understanding of their cellular, synaptic, and molecular properties, as well as the mechanisms that trigger their activation during cataplexy and make them susceptible in RBD.

Relationship between Sleep Quality and Shoulder Disorders in People with Stroke

Background and objective: The primary aim of the study was to investigate the relationship between sleep quality (SQ) and shoulder disorders in people after a stroke. The secondary aim was to explore the relationship between SQ and stroke outcomes, including the impact of stroke, fatigue, and quality of life (QOL). Material and Methods: A sample of 94 stroke patients was included. The Pittsburgh Sleep Quality Index (PSQI) was used to assess SQ, whereas the Shoulder Pain and Disability Index (SPADI) was utilized to assess shoulder pain and disability. The Stroke Impact Scale 16, the Modified Fatigue Impact Scale, and the Medical Outcomes Study Short Form 12 were also used as secondary measures. Results: The prevalence of poor SQ, shoulder pain, and shoulder disability in our sample was 60%, 78%, and 85%, respectively. The global PSQI score had a significant association with the SPADI pain subscale. There were some significant correlations between the PSQI subscales and shoulder pain and disability. The PSQI significantly correlated with stroke recovery, fatigue, and QOL. The daytime dysfunction PSQI subscale was significantly correlated with all shoulder and stroke outcomes and their subscale. Conclusion: SQ was associated more with the non-motor outcomes of stroke, including pain, cognitive fatigue, and mental status, than the motor outcomes. Considering SQ during upper extremity rehabilitation and care processes is essential.

Sleep and Stroke: Opening Our Eyes to Current Knowledge of a Key Relationship

PURPOSE OF REVIEW

To elucidate the interconnection between sleep and stroke.

RECENT FINDINGS

Growing data support a bidirectional relationship between stroke and sleep. In particular, there is strong evidence that sleep-disordered breathing plays a pivotal role as risk factor and concur to worsening functional outcome. Conversely, for others sleep disorders (e.g., insomnia, restless legs syndrome, periodic limb movements of sleep, REM sleep behavior disorder), the evidence is weak. Moreover, sleep disturbances are highly prevalent also in chronic stroke and concur to worsening quality of life of patients. Promising novel technologies will probably allow, in a near future, to guarantee a screening of commonest sleep disturbances in a larger proportion of patients with stroke. Sleep assessment and management should enter in the routinary evaluation of stroke patients, of both acute and chronic phase. Future research should focus on the efficacy of specific sleep intervention as a therapeutic option for stroke patients.