Monotonous driving induces shifts in spatial attention as a function of handedness.

Current evidence suggests that the ability to detect and react to information under lowered alertness conditions might be more impaired on the left than the right side of space. This evidence derives mainly from right-handers being assessed in computer and paper-and-pencil spatial attention tasks. However, there are suggestions that left-handers might show impairments on the opposite (right) side compared to right-handers with lowered alertness, and it is unclear whether the impairments observed in the computer tasks have any real-world implications for activities such as driving. The current study investigated the alertness and spatial attention relationship under simulated monotonous driving in left- and right-handers. Twenty left-handed and 22 right-handed participants (15 males, mean age = 23.6 years, SD = 5.0 years) were assessed on a simulated driving task (lasting approximately 60 min) to induce a time-on-task effect. The driving task involved responding to stimuli appearing at six different horizontal locations on the screen, whilst driving in a 50 km/h zone. Decreases in alertness and driving performance were evident with time-on-task in both handedness groups. We found handedness impacts reacting to lateral stimuli differently with time-on-task: right-handers reacted slower to the leftmost stimuli, while left-handers showed the opposite pattern (although not statistically significant) in the second compared to first half of the drive. Our findings support suggestions that handedness modulates the spatial attention and alertness interactions. The interactions were observed in a simulated driving task which calls for further research to understand the safety implications of these interactions for activities such as driving.

The relationship between alertness and spatial attention under simulated shiftwork.

Higher and lower levels of alertness typically lead to a leftward and rightward bias in attention, respectively. This relationship between alertness and spatial attention potentially has major implications for health and safety. The current study examined alertness and spatial attention under simulated shiftworking conditions. Nineteen healthy right-handed participants (M = 24.6 ± 5.3 years, 11 males) completed a seven-day laboratory based simulated shiftwork study. Measures of alertness (Stanford Sleepiness Scale and Psychomotor Vigilance Task) and spatial attention (Landmark Task and Detection Task) were assessed across the protocol. Detection Task performance revealed slower reaction times and higher omissions of peripheral (compared to central) stimuli, with lowered alertness; suggesting narrowed visuospatial attention and a slight left-sided neglect. There were no associations between alertness and spatial bias on the Landmark Task. Our findings provide tentative evidence for a slight neglect of the left side and a narrowing of attention with lowered alertness. The possibility that one's ability to sufficiently react to information in the periphery and the left-side may be compromised under conditions of lowered alertness highlights the need for future research to better understand the relationship between spatial attention and alertness under shiftworking conditions.

The influence of body mass on long-term cognitive performance of children treated for sleep-disordered breathing.

BACKGROUND: Long-term follow-up of children treated for sleep-disordered breathing (SDB) is limited, as the examination of factors potentially contributing to recovery is also limited. This study aimed to examine whether the recovery of neurocognitive function is achieved at four years post-adenotonsillectomy for SDB in children and whether body mass status influences the outcome. METHODS: This prospective longitudinal study of 3- to 12-year-old children recruited from an otolaryngology clinic compared cognitive performance, sleep, ventilation, and body mass before and at four years post-adenotonsillectomy in children with SDB and compared these parameters to those of untreated healthy controls during the same time points. RESULTS: Children were categorised as normal-weight control (n = 33), normal-weight SDB (n = 18), or overweight/obese SDB (n = 11). Body mass did not significantly differ at four year follow-up compared to the baseline in any subgroup (p > 0.05), and groups were matched on the basis of age and gender. Despite improved sleep and nocturnal ventilation at four years post-adenotonsillectomy, little gain was observed in neurocognitive performance in either nonobese or overweight/obese children with SDB. Overweight/obese children with SDB displayed worse neurocognitive performance than all other children. CONCLUSION: Adenotonsillectomy improves nocturnal ventilation and sleep quality but not neurocognitive performance in the long term. Excess body mass may place children with SDB at increased risk of neurocognitive performance deficits.