Cerebral autoregulation improves in epilepsy patients after temporal lobe surgery
Dütsch M, Devinsky O, Doyle W, Marthol H, and Hilz MJ (2004) Cerebral autoregulation improves in epilepsy patients after temporal lobe surgery. J Neurol 251:10 1190–7.
Abstract: Patients with temporal lobe epilepsy (TLE) often show increased cardiovascular sympathetic modulation during the interictal period, that decreases after epilepsy surgery. In this study, we evaluated whether temporal lobectomy changes autonomic modulation of cerebral blood flow velocity (CBFV) and cerebral autoregulation. We studied 16 TLE patients 3-4 months before and after surgery. We monitored heart rate (HR), blood pressure (BP), respiration, transcutaneous oxygen saturation (sat-O(2)), end-expiratory carbon dioxide partial pressure (pCO(2)) and middle cerebral artery CBFV. Spectral analysis was used to determine sympathetic and parasympathetic modulation of HR, BP and CBFV as powers of signal oscillations in the low frequency (LF) ranges from 0.04-0.15Hz (LF-power) and in the high frequency ranges from (HF) 0.15-0.5Hz (HF-power). LF-transfer function gain and phase shift between BP and CBFV were calculated as parameters of cerebral autoregulation. After surgery, HR, BP(mean), CBFV(mean), respiration, sat-O(2), pCO(2) and HF powers remained unchanged. LF-powers of HR, BP, CBFV and LF-transfer function gain had decreased while the phase angle had increased (p<0.05). The reduction of LF powers and LF-gain and the higher phase angle showed reduced sympathetic modulation and improved cerebral autoregulation. The enhanced cerebrovascular stability after surgery may improve autonomic balance in epilepsy patients.
Keywords: epilepsy surgery, autonomic nervous system, cerebral autoregulation, interictal sympathetic tone, cerebral blood flow velocity
- 16 patient study comparing cerebral blood flow before and after surgery for temporal lobe epilepsy. The phase relation between systemic BP and cerebral blood flow was used as an indicator of cerebral autoregulation. Decreased gain of the low-frequency component of systemic BP and increased phase angle after surgery were interpeted as indicating less direct coupling of the systemic circulation to the cerebral, that is, improved cerebral autoregulation.