A rhesus-monkey experiment linked methamphetamine-disrupted sleep with poorer next-day cognitive performance. It provides controlled animal evidence relevant to sleep as a contributing factor, without establishing that sleep disruption alone caused every deficit.
Borgatti and colleagues studied five adult rhesus monkeys, four male and one female. Methamphetamine doses of 0.3 and 0.56 mg/kg were given intramuscularly three hours before lights off. Collar-mounted actigraphy assessed sleep-related movement patterns. The following day, monkeys completed a touchscreen attentional set-shifting task.
The study thus connected a defined exposure, an intervening sleep period and later behavior. It did not involve human drivers, an on-road task or a clinical sleep diagnosis.
At 0.56 mg/kg, sleep efficiency decreased and wake time, sleep latency and fragmentation increased significantly relative to baseline. Those sleep comparisons were not significant at 0.3 mg/kg. The higher dose also produced significant increases in total trials, errors and perseverative errors and lower mean task accuracy.
The lower dose was not entirely without a cognitive effect: total perseverative errors increased significantly. Reporting only the stronger high-dose pattern would omit that result. The number of days needed to complete the task did not differ significantly.
Greater wake time and lower sleep efficiency correlated with poorer cognition across conditions. That relationship is consistent with sleep contributing to next-day difficulties. It does not isolate sleep from residual drug effects or other consequences of exposure. A separate manipulation would be needed to establish how much impairment was specifically mediated by sleep.
Actigraphy estimates sleep from movement; it is not identical to polysomnography. The very small animal sample, administration route and experimental schedule also limit transfer to human cases.
The paper supports treating sleep history as a substantive part of a case review rather than assuming concentration alone explains behavior. It cannot quantify impairment in a particular human. Contrast this animal experiment with the conditions of a controlled human simulator study.