Autonomic consequences of brainstem infarction

Objective: It is well known that patients with brainstem infarctions someti mes experience dizziness, vertigo and falls, although the exact mechanism i s not clear. Therefore, we designed a study to quantify autonomic function in patients with brainstem infarction. Patients and methods: We examined au tonomic function in 15 patients with brainstem infarctions, who had a histo ry of vertigo, nausea, floating sensation and/or general fatigue during sta nding, and 31 age-matched controls using the composite autonomic scoring sc ale (CASS), which was used to grade autonomic function. The patients underw ent initial autonomic assessment and then were subjected to aniracetam ther apy. The drug was given orally (dose of 600 mg/day) for a duration of 56 da ys. Upon completion of aniracetam administration, the CASS was again tested . Results: Upon initial assessment, the patients had mild reductions in mea n blood pressure (MBP) and lack of an increasing heart rate (HR) within 5 m in of head up-tilt, an impairment in BP correction during late phase II and reduced phase IV beat-to-beat BP response to the Valsalva maneuver, and re duced heart rate response to deep breathing (HRdb). CASS indicated mild aut onomic dysfunction. After 8 weeks of treatment with aniracetam, the patient s' symptoms improved and the autonomic tests showed improvement in autonomi c function. Conclusion: Part of the pathogenesis of recurrent vertigo or di zziness with brainstem infarction might be due to mild autonomic dysfunctio n. Aniracetam, which activates the cholinergic system in blain, might corre ct the cardiovagal system in these patients. The CASS may be a sensitive to ol for assessing mild autonomic dysfunction in patients with brainstem infa rction. (C) 2001 Published by Elsevier Science B.V.