Autonomic, EEG, and Behavioral Arousal Signs in a PVS Case After Zolpidem Intake

Several reports have been published over recent years about the paradoxical "arousing" effect of Zolpidem, a highly selective nonbenzodiazepine gamma aminobutyric acid (GABA) agonist acting on the [omega]-1 site of the GABA A receptor, in persistent vegetative state (PVS), in minimally conscious state (MCS) patients, ischemic stroke cases, after brain injury, and in patients suffering hypoxic encephalopathy. 1 We describe here this paradoxical arousing effect in a PVS case assessing autonomic, electroencephalographic (EEG), and behavioral changes, after Zolpidem uptake.This case report is the first to show the importance of using heart rate variability (HRV) methodology and EEG to assess autonomic and brain functional changes in a PVS case, during this pharmacological intervention. METHODSWe studied a 21-year-old female patient (YOR), who had suffered a stroke causing a top of the basilar artery syndrome and who had been in PVS for five years.Magnetic resonance imaging showed destruction of the rostral part of the pons, the mesencephalon, and both thalami.The patient showed circadian wakefulness, although she maintained longer periods of time with her eyes closed.With informed written consent of her parents, 10 mg of Zolpidem were administered through a percutaneous endoscopic gastrostomy.A control healthy subject (DMC) matched for age and gender, without any history of autonomic or any other nervous system disorder, non-smoker, and who was not under any medication was also included.Zolpidem 10 mg dissolved in 30 ml saline solution was administered orally to subject DMC.This pharmacologic intervention was approved by the Institute of Neurology and Neurosurgery Ethics Committee, Havana, Cuba. Electroencephalographic studiesElectroencephalographic records were obtained by the digital MEDICID-05 system (Neuronic S.A.), with the following technical parameters: gain 20,000, filters pass-band 0.1-30 Hz, 60 Hz "notch" filter, level of noise 2μv root mean square, sampling period of 5 ms, and environmental temperature of approximately 23°C.Nineteen monopolar leads were placed according to the International 10/20 System, using EEG Ag-AgCl scalp electrodes, with linked ear lobes as a reference.Electrode-skin impedance was lower than 10 KΩ.Total time of recording was 75 minutes.The EEG records were independently