Diurnal variations in quantitative pupillary reactivity in large hemispheric strokes

Abstract This study investigated the impact of diurnal variation on quantitative pupillary reactivity in stable patients with large hemispheric strokes. We included 35 patients with large hemispheric stroke without neurological worsening. Quantitative pupillometry was performed every 4 h. Pupillometer values for pupil size, percentage of constriction (%CH), constriction velocity (CV), dilation velocity (DV), and neurological pupil index (NPi) were collected. We evaluated changes in PLR parameters over time using linear mixed model analysis. Among the included patients (n = 35), 951 pupillometer measurements were analyzed. Significant diurnal variations were observed in pupil maximum size, %CH, CV, and DV at 4 AM compared with values at 8 PM. At 4 AM, patients had a significantly larger pupil (right [Rt] 3.59 vs 3.21 mm, P < 0.001; left [Lt] 3.51 vs 3.18 mm, P < 0.001) and higher %CH (Rt 31.48 vs 25.72, P < 0.001; Lt 31.42 vs 24.98, P < 0.001), CV (Rt 1.97 vs 1.68 mm/s, P < 0.001; Lt 1.98 vs 1.65 mm/s, P < 0.001), and DV (Rt 0.97 vs 0.84 mm/s, P < 0.001; Lt 0.94 vs 0.82 mm/s, P = 0.001). Pupillary dynamics demonstrated diurnal variations over 24 h within normal ranges in large hemispheric strokes without neurological worsening.