Systemic autonomic involvement in episodic cluster headache: a comparison between active and remission periods.

In this study we compared systemic autonomic involvement in episodic cluster headache during active and silent periods. Seventeen patients were studied with sympathetic skin response, lying to standing test, Valsalva manoeuvre, deep breathing test and orthostatic hypotension evaluation. Each of them underwent these tests during active and silent periods. Values were then compared with normal controls. Our data show a parasympathetic, but not sympathetic, involvement. Moreover, this impairment seems to be "chronic", as it persists beyond the active period.