Body mass index and neuropsychological and emotional variables: joint contribution for the screening of sleep apnoea syndrome in obese.

Objective: Obstructive sleep apnoea (OSA) is the most common sleep disorder and its prevalence has increased with the obesity pandemic. We aimed to explore the presence of OSA in severe obesity and to evaluate the association of body mass index (BMI) with sleep architecture, cognition, emotional distress and comorbidities in OSA versus non-OSA patients.

Methods: A sample of 61 patients performed a neuropsychological battery that included tasks of attention, memory, perceptual/visuospatial ability, vocabulary, inhibition, cognitive flexibility and distress symptomatology, before overnight polysomnography.

Results: More than half of the sample had OSA. Excessive daytime sleepiness was not a prominent complaint. Sleep architecture was worse in the OSA than in the non-OSA group, and hypertension was increased with OSA, especially in the severe OSA group. A higher BMI was associated with cognitive distress and sleep variables and with type 2 diabetes. The apnoea-hypopnoea index (AHI) was correlated with gender and cognitive measurements. Cognitive complaints were associated with enhanced distress in both OSA and non-OSA patients.

Discussion: OSA is considerably present in severely obese patients. The BMI was strongly associated with other important anthropometric measurements along with worsening sleep architecture and lower executive functioning, both of which may contribute to weight gain. The AHI was significantly higher in men and affected memory and maintaining sets on the Wisconsin Card Sorting Test which may represent a barrier to treatment adherence for this disorder. The substantial presence of cognitive complaints in OSA and non-OSA patients suggests the need for psychological intervention focused on adaptive coping strategies, mostly for depressive symptoms. Given the current obesity epidemic, these results support the need for routine sleep investigation in obese people, particularly in primary care settings. BMI, neuropsychological and emotional screening can provide crucial information about asymptomatic and high-risk patients who require prompt sleep intervention and obesity treatment.