[Nyctohemeral incidence of acute cerebral vasculopathies].

The time of onset of the neurological symptomatology was studied retrospectively in 258 patients, 107 (41%) autopsized, affected by non embolic cerebral infarction (172 cases), cerebral haemorrhage (52 cases) and subarachnoid haemorrhage (24 cases). In the patients suffering from cerebral infarction or haemorrhage the symptomatology began more frequently in the morning hours (from 6 to 12 a.m.) while it was comparatively rare in the night (from 00 to 06 am.). and evening hours (from 6 to 12 p.m.). This difference was significant (p less than 0.01) at the chi-squared test. The patients with subarachnoid haemorrhage showed a more homogeneous distribution with a higher but not significant frequency in the morning hours. The nyctohemeral distribution does not significantly differ in the patients affected by cerebral infarction, cerebral haemorrhage and subarachnoid haemorrhage. The time of onset of the neurological symptomatology shows no significant variation in the patients with cerebral and subarachnoid haemorrhage after dividing them in normotensives and hypertensives, while in the hypertensive patients with cerebral infarction a significant higher frequency of strokes was observed in the night hours (from 00 to 06 a.m.).