Neuromuscular disorders and sleep

Subjective Sleep Quality as it Relates to Cognitive and Physical Function in Spinal Muscular Atrophy Patients

Sleep quality and its association with cognition has been widely studied in some neurodegenerative diseases, but less is known about this association in spinal muscular atrophy (SMA). In adult SMA (n = 21) patients and age-matched controls (n = 23), we assessed subjectively measured sleep quality and daytime somnolence. Cognition was assessed with a multi-domain neuropsychological battery. Further, we investigated the association between clinical functional scores and sleep questionnaire scores. Among SMA patients, better motor and limb function was associated with better subjective sleep quality (p's<  0.05). Clinicians should consider sleep quality in patient care and future studies are needed to better understand these relationships.

The Prognostic Role of Obstructive Sleep Apnea at the Onset of Amyotrophic Lateral Sclerosis

BACKGROUND/OBJECTIVE

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the progressive loss of central and peripheral motor neurons. Some studies have found discordant data in the presence of sleep apnea in ALS patients. An obstructive component also occurs with upper airways hypotonia and muscle weakness that may result in an excessive reduction of airway lumen, leading to obstructive sleep apnea (OSA). The aim of this study was to assess the role of obstructive apneic events at disease onset in the ALS prognosis.

METHODS

A longitudinal retrospective study was conducted on 42 clinically diagnosed ALS patients. The study population was divided into 2 groups according to their obstructive apnea/hypopnea index (AHIo): group 1 consisted of 20 patients with an AHIo ≥5 and group 2 consisted of 22 patients with an AHIo <5. Both groups were compared with regard to demographic, polygraphic, and respiratory function parameters as well as ALS characteristics (bulbar onset, time between onset and first check-up, time between diagnosis and first check-up, time between first check-up and death or tracheostomy).

RESULTS

The mean survival in ALS patients with an AHIo ≥5 was significantly shorter than in ALS without OSA (p = 0.0237). The sniff nasal inspiratory pressure test was significantly correlated with AHIo, time of oxyhemoglobin saturation below 90% and the oxyhemoglobin desaturation index (p < 0.0001).

CONCLUSIONS

Our study highlights the importance of an early diagnosis of OSA in ALS patients, allowing the identification of ALS patients with an OSA phenotype (AHIo ≥5), who are characterized by a worse prognosis.

Sleep disorders in neuromuscular diseases

PURPOSE OF REVIEW

Patients with neuromuscular disorders (NMD) are especially vulnerable to sleep-related dysfunction. Sleep-disordered breathing often precedes diurnal respiratory failure in NMD patients, requiring timely recognition and management with noninvasive ventilation (NIV). This paper reviews the mechanisms, diagnostic evaluation, and management of sleep disorders in various neuromuscular diseases.

RECENT FINDINGS

The severity, duration, and type of NMD influence the pattern of sleep disturbance. Several investigators have addressed other clinical aspects including rating scales for sleep complaints, hypocretin-1 deficiency, excessive daytime somnolence, and relation of sleep disorder with length of CTG trinucleotide repeats in myotonic dystrophy. Benefits of NIV on quality of life and survival in adults and children with chronic NMD are well established, and recently have been documented even in patients with nocturnal hypoventilation and daytime normocapnia. In contrast, the timing for investigation with polysomnography and for initiation of NIV is debated.

SUMMARY

Patients with chronic NMD should be routinely assessed for sleep-disordered breathing and sleep complaints, because these are treatable complications in an otherwise progressive disease process. Further research is needed to establish the indications for polysomnography and to determine the optimal timing for initiating NIV to treat sleep-disordered breathing in patients with neuromuscular diseases.