Purpose: To illustrate the beneficial effect of zolpidem on the neuropsychiatric and motor symptoms in a patient with Parkinson disease (PD) after bilateral subthalamic nucleus deep brain stimulation.
Case report: The 61-year-old housewife was diagnosed to have PD for 12 years with initial presentation of clumsiness and rest tremor of right limbs. She was referred to our hospital in March 2009 due to shortening of drug beneficial period since 3 years ago and on-phase dyskinesia in recent 2 years. Bilateral STN DBS was conducted on 18 June, 2009. Fluctuating spells of mental confusion were developed on the next day after surgery. Electric stimuli via DBS electrodes were delivered with parameters of 2 volts, 60 μs, 130 Hz on bilateral STN 32 days after DBS. The incoherent behaviors and motor fluctuation remained to occur. The beneficial effect of zolpidem on her neuropsychiatric and motor symptoms was detected incidentally in early July 2009. She could chat normally with her caregiver and walk with assistance after taking zolpidem. The beneficial period may last for 2 hours. Zolpidem was then given in dosage of 10 mg three times per day. The neuropsychiatric inventory was scored 56 during zolpidem 'off' and 30 during zolpidem 'on'. To understand the intriguing feature, we conducted FDG-PET during 'off' and 'on' zolpidem conditions. The results revealed that the metabolism was decreased in the right frontal, parietal cortex and caudate nucleus during zolpidem 'off'. These cool spots can be partially restored by zolpidem.
Conclusion: Zolpidem ameliorated the neuropsychiatric and parkinsonian motor symptom in the PD patient. Since GABAA benzodiazepine receptors are widely distributed throughout the central nervous system, zolpidem probably acts via modulating structures lying within the cortico-subcortical loop or by direct effect on these cortical regions.