Heart rate does not decrease after right hemispheric amobarbital injection
Jokeit H, Noerpel I, Herbord E, and Ebner A (2000) Heart rate does not decrease after right hemispheric amobarbital injection. Neurology 54:12 2347–8.
First Paragraph: Ten years ago it was reported that the heart rate of 25 patients with different focal epilepsies changed following unilateral hemispheric inactivation by intracarotid amobarbital injection (Wada Test). Using mean amobarbital dosages of 126 and 128 mg, the authors showed heart rate increases after left hemisphere inactivation and decreases following right hemisphere inactivation. It was concluded that the results are consistent with differential left/right cerebral hemispheric effects on autonomic function. Within 9 years after publication, this study was cited by 59 publications as reported by the Science Citation Index. However, only one of these studies was aimed at reproducing the results. In this study, 32 patients with temporal lobe epilepsy (TLE) and with left hemisphere speech dominance were investigated using 200 mg amobarbital. The patients demonstrated an increase of heart rate immediately after each injection but no difference in heart rate between the sides of injection.
Context
- Attempt to reproduce finding of Zamrini et al., given the contradictory findings of Reuter et al. In 59 right handed patients with unilateral TLE (34 on left side), with injection of amobarbital into one side then the other at 30 minute delay. Both injections led to increased heart rate, arguing against Zamrini et al. As the authors point out, the effect observed by Zamrini was fairly small and may have been due to outliers.