Serial NIHSS scores in patients with acute cerebral infarction

Aim To study time course of neurological deficits in patients with acute cerebral infarction admitted shortly after stroke onset. Methods Serial NIHSS scores were obtained whenever feasible in patients admitted because of cerebral infarction within 3 h of symptom onset. Patients receiving and not receiving thrombolysis were compared. Short-term outcome was defined as NIHSS score and modified Rankin score 7 days after stroke onset. The hyperacute phase was defined as the time between stroke onset and the 6- to 9-h interval after stroke onset, acute phase as the time between the 6- to 9-h interval and the 21 to 27-h interval, and the subacute phase as the time between the 21- to 27-h interval and 7 days after stroke onset. Results Serial NIHSS scores were obtained in 552 patients within three hours of stroke onset. There was a significant improvement (P < 0.001) comprising 62% of the total improvement in the hyperacute phase. There was no significant improvement in the acute phase and a small significant improvement in the subacute phase (P < 0.01). Conclusion Our study demonstrates a hyperacute phase with rapid improvement probably due to early recanalization, an acute phase with no significant improvement and slow improvement in the subacute phase. Different pathophysiological mechanisms are likely involved in the different phases.