PT - JOURNAL ARTICLE AU - Francois Alexandre AU - Nelly Heraud AU - Anthony Sanchez AU - Nicolas Oliver AU - Philippe Guerin AU - Candau Robin AU - Alain Varray TI - Role of nocturnal desaturation on motor cortex impairment in COPD DP - 2014 Sep 01 TA - European Respiratory Journal PG - P4742 VI - 44 IP - Suppl 58 4099 - http://erj.ersjournals.com/content/44/Suppl_58/P4742.short 4100 - http://erj.ersjournals.com/content/44/Suppl_58/P4742.full SO - Eur Respir J2014 Sep 01; 44 AB - Brain impairment is a major systemic effect in COPD and contributes to peripheral muscle weakness. Cerebrovascular response (i.e. an increase in cerebral blood flow) to hypoxia protects the brain against the effects of chronic hypoxemia. However, during sleep, patients are highly exposed to brain alterations as this response is abolished (Meadows et al. J Appl Physiol 97:1343-48, 2004). In this study, we hypothesized the involvement of nocturnal desaturation in altering the brain and decreasing cortical motor output in COPD.24 COPD patients (GOLD 2 and 3) and 11 healthy controls underwent a polysomnography. COPD patients were divided in 2 groups: nocturnal desaturators (Ndes) if they spent more than 10% of the total sleep time with a SpO2<90%, otherwise non desaturators (NNdes). Serum S100b concentration was measured on awakening as a marker of cerebral lesions. Quadriceps peak twitches (TwQ) were measured during and after quadriceps maximal voluntary contractions (QMVC). Level of voluntary activation was assessed by interpolated twitches and magnetic stimulation of motor cortex (respectively LOA and VAcortical).Serum S100b was twice higher in Ndes (p<0.05). LOA and VAcortical were significantly lower in Ndes compared to NNdes and controls (p<0.05). TwQ and QMVC were decreased in COPD patients compared to controls, but there was no significant difference between Ndes and NNdes.Higher serum S100b was consistent with higher cerebral lesions in nocturnal desaturators, which may explain the lower muscle activation and cortical output impairment. Surprisingly, QMVC was not different between NNdes and Ndes, suggesting compensatory mechanism(s) to ensure comparable muscle strength despite motor cortex impairment.