LAUSR

Objectives Type 2 diabetes mellitus (T2DM) is linked with a risk of dementia and decline in neurocognitive function. The current observational case-control study was conducted to evaluate the effect of fasting during Ramadan on cognitive functions and fatigue severity in T2DM patients using the Cambridge Neuropsychological Test Automated Battery (CANTAB). Methods This research was conducted at King Saud University Medical city, on 82 subjects including 43 control and 39 T2DM patients of both genders. The standardized Fatigue Severity Scale (FSS) and tests from CANTAB, including the Motor Screening Task (MOT), Spatial Span (SSP) and Intra-Extra Dimensional Set Shift (IED) were recorded during 3rd week and 2–3 weeks after Ramadan under controlled environmental conditions. Neurocognitive functions were recorded through CANTAB. Results IED errors (24.43 vs 50.73, p = 0.007), MOT mean and median latency (1466.32 vs 1120.27, p = 0.002) were significantly higher in T2DM than controls. IED stages completed (7.43 vs 8.69, p = 0.003) and SSP Span length were significantly lower in T2DM than controls (4.13 vs 4.82, p = 0.059). The significant differences between T2DM patients and controls persisted in the post. T2DM patients made more errors and completed less IED stages than did the controls, indicating that a worsened flexibility of attention relative to controls. Moreover, T2DM patients exhibited longer latencies in MOT, indicating poor motor performance. A comparison of performances by T2DM patients on FSS and CANTAB during and after Ramadan showed that fasting substantially increased fatigue scales, motor performance, and working-memory capacity. Conclusions Patients with T2DM have impaired cognitive functions including poor motor performance, low flexibility of attention, and poor working memory capacity compared to healthy control subjects during and also in post Ramadan period. However, there is no clear statistical evidence that the cognitive functions (except for SSP SL scores) and fatigue severity of T2DM subjects differ between Ramadan and after Ramadan in both T2DM and controls.