Clinical implication of time of stroke among post stroke survivors from eastern India: A circadian perspective

IntroductionThe circadian variation in stroke occurrence is a well-documented phenomenon. However, the circadian effect on stroke outcome, particularly on post-stroke cognition, is not yet been fully elucidated. Aims and objectiveWe aim to evaluate the influence of diurnal variation of stroke onset upon post-stroke cognition and development of post-stroke depression. Materials and MethodsBased on 4-hourly time period of stroke occurrence, 249 recruited cohorts were categorized into 6 groups. Several clinical and cognitive parameters were compared among the groups. Then, the mRNA expression of core clock genes in Peripheral Blood Mononuclear Cells were quantified and correlated with post stroke outcome among 24 acute phase cases with day-time or night-time stroke occurrence. Furthermore, the genetic susceptibility towards higher number of cases in morning were examined by genotyping CLOCK (rs1801260T/C, rs4580704G/C) and CRY2 (rs2292912C/G) genes variants in cases and 292 controls. Results and conclusionAmong the six subgroups, the subgroup-1 represents the nocturnal-onset stroke cases; they were identified to have higher NIHSS score (12.2{+/-}5.67) at the time of admission than other subgroups (8.73{+/-}5.92). In the same cohort, more number of diabetic individuals with higher fasting blood sugar level (186.57{+/-}93.40) was also observed. After 6 months, those with nocturnal-onset stroke had higher prevalence of language impairment and depression score. A significant decrease in mRNA level of BMAL1 and CRY1 genes correlated with raw score for language and depression; data in nocturnal onset cases further established our observation. However, the higher incidence of stroke in day time did not reveal any genetic correlation.