Dados do Trabalho

Título

Correlation between REM and NREM respiratory polysomnographic variables in children with neuromuscular disorders.

Introdução

Neuromuscular disorders (NMD) cover a range of genetic diseases that are usually progressive and characterized by skeletal muscle weakness, including diaphragm. Skeletal muscle weakness has a major responsibility on sleep breathing disorders (SBD), since there are no validated questionnaires for children as a screening tool. The current gold standard for SBD diagnosis is Polysomnography (PSG) with capnography, however, little is known about the correlation between muscle strength and PSG variables, particularly when it comes to the differentiation among REM and non-REM variables.

Objetivo

The main goal was to analyze the difference in polysomnographic and respiratory findings among neuromuscular disorders´ patients with reduced muscle strength during NREM and REM sleep.

Métodos

We analyzed 30 patients with neuromuscular disorders and divided them into groups according to muscle strength level and region (proximal and distal upper and lower limbs and cervical region). We also divided apnea hypopnea index (AHI) and minimal oxygen saturation (SaO2) between REM and NREM sleep and analyzed it by means of Mann-Whitney U test. Then, we compared these features among the reduced muscle strength groups by means of t Student test.

Resultados

Our sample was composed of 30 children and adolescents aged 4 to 19 years (10 ± 4). 20 of them were diagnosed with Duchenne Muscular Dystrophy (DMD) and 23 had reduced proximal lower limbs muscle strength. This group presented medium NREM AHI of 4,31 ± 4,74 versus medium REM AHI of 12,72 ± 14,68 with statistical significance (p = 0,002). The reduced distal lower limbs muscle strength group was composed of 14 individuals and presented medium NREM AHI of 5,37 ± 5,36 against medium REM AHI of 13,85 ± 14,39 also with statistical significance (p = 0,01). In relation to minimal SaO2 we found no difference statistically significant in this sample.

Conclusões

The measure of muscle strength is proving to be an anticipatory sign of SBD, as well as its severity, emphasizing a huge concern about the REM sleep breathing pattern and its consequences. The lower limbs correlation with worse AHI may be due to the progression design of the most prevalent disease: DMD.
Although our sample was small, we believe that this data can be used as a tool to address respiratory disease progression.

Palavras -chave

neuromuscular disorders
apnea hypopnea index
strength level
REM sleep
NREM sleep