Impact of Obstructive Sleep Apnea Syndrome in P300 Latency

Abstract

Objective: Evaluate the impact and linear correlation between Obstructive Sleep Apnea Syndrome (OSAS) and P300 latency. It also aimed to identify which variables of polysomnography and scales of excessive daytime sleepiness best correlate with the increase in P300 latency.

Method: This is a survey study, conducted between March 2010 and January 2011, in which polysomnography, scales of sleepiness and P300 latency from 54 patients were analyzed. These results were evaluated in patients with different stages of OSAS, using as independent variables: sleep stages, arousals, apnea/hyponea index(AHI), oxyhemoglobin desaturation and limb movements (PLM).

Results: All patients were male, mean age 41.3 ± 2.1 years, body mass index of 29.3 ± 1.2 kg/m² and hearing threshold in17.1 ± 1.3 dB. According to the AHI, the patients were divided into normal (n = 15), mild (n = 14), moderate (n = 9), and severely increased (n = 16). It was found the following correlations with P300 latency: Epworth scale (r = 0.33; P = .2), Karolinska scale (r=-0.14; P = .55), Stanford scale (r=0.01; P = .29), sleep efficiency (r = 0.11; P = .83), percentage of N3(r = -0.48; P = .24) and REM (r = -0.18; P = .13), arousals index (r=0.74; P < .05), AHI (r = 0.99; P < .01), oxyhemoglobin desaturation index (r = 0.99; P < .01), PLM (r=0.44; P < .01), mean oxyhemoglobin saturation (r = -0.84; P < .01) and minimum oxyhemoglobin desaturation (r = -0.85; P < .01).

Conclusion: The apnea/hypopnea index, arousals, oxyhemoglobin desaturation index and periodic limb movements were positively correlated with P300 latency (P < .05). The average and minimum oxyhemoglobin saturation exhibited negative correlation with P300 latency (P < .01). No statistically significant correlation was seen between P300 latency and sleepiness scales, as well as REM and N3 sleep stage percentage.