Impaired vigilance and increased accident rate in public transport operators is associated with sleep disorders

Sleep disturbances can impair alertness and neurocognitive performance and increase the risk of falling asleep at the wheel. We investigated the prevalence of sleep disorders among public transport operators (PTOs) and assessed the interventional effects on hypersomnolence and neurocognitive function in those diagnosed with obstructive sleep apnea (OSA).

Overnight polygraphy and questionnaire data from 101 volunteers (72 males, median age 48 range [22-64] years, 87 PTOs) employed at the Gothenburg Public Transportation Company were assessed. Treatment was offered in cases with newly detected OSA. Daytime sleep episodes and neurocognitive function were assessed before and after intervention.

At baseline, symptoms of daytime hypersomnolence, insomnia, restless legs syndrome as well as objectively assessed OSA (apnea hypopnea index (AHI, determined by polygraphic recording)=17[5-46]n/h) were highly present in 26, 24, 10 and 22%, respectively. A history of work related traffic accident was more prevalent in patients with OSA (59%) compared to those without (37%, p<0.08). In the intervention group (n=12) OSA treatment reduced AHI by -23 [-81 to -5]n/h (p=0.002), determined by polysomnography. Reduction of OSA was associated with a significant reduction of subjective sleepiness and blood pressure. Measures of daytime sleep propensity (microsleep episodes from 9 [0-20.5] to 0 [0-12.5], p<0.01) and missed responses during performance tests were greatly reduced, indices of sustained attention improved.

PTOs had a high prevalence of sleep disorders, particularly OSA, which demonstrated a higher prevalence of work related accidents. Elimination of OSA led to significant subjective and objective improvements in daytime function. Our findings argue for greater awareness of sleep disorders and associated impacts on daytime function in public transport drivers.