title: Subthalamic nucleus stimulation and somatosensory temporal discrimination in Parkinson's disease.
abstract: Whereas numerous studies document the effects of dopamine medication and deep brain stimulation on motor function in patients with Parkinson's disease, few have investigated deep brain stimulation-induced changes in sensory functions. In this study of 13 patients with Parkinson's disease, we tested the effects of deep brain stimulation on the somatosensory temporal discrimination threshold. To investigate whether deep brain stimulation and dopaminergic medication induce similar changes in somatosensory discrimination, somatosensory temporal discrimination threshold values were acquired under four experimental conditions: (i) medication ON/deep brain stimulation on; (ii) medication ON/deep brain stimulation off; (iii) medication OFF/deep brain stimulation on; and (iv) medication OFF/deep brain stimulation off. Patients also underwent clinical and neuropsychological evaluations during each experimental session. Somatosensory temporal discrimination threshold values obtained in patients were compared with 13 age-matched healthy subjects. Somatosensory temporal discrimination threshold values were significantly higher in patients than in healthy subjects. In patients, somatosensory temporal discrimination threshold values were significantly lower when patients were studied in medication ON than in medication OFF conditions. Somatosensory temporal discrimination threshold values differed significantly between deep brain stimulation on and deep brain stimulation off conditions only when the patients were studied in the medication ON condition and were higher in the deep brain stimulation on/medication ON than in the deep brain stimulation off/medication ON condition. Dopamine but not subthalamic nucleus deep brain stimulation restores the altered somatosensory temporal discrimination in patients with Parkinson's disease. Deep brain stimulation degrades somatosensory temporal discrimination by modifying central somatosensory processing whereas dopamine restores the interplay between cortical and subcortical structures.
authors.affiliation: Department of Neurological Sciences, Sapienza University of Rome, Viale dell'Università 30, Rome, Italy.
authors.forename: Antonella
authors.initials: A
authors.lastname: Conte
authors.forename: Nicola
authors.initials: N
authors.lastname: Modugno
authors.forename: Francesco
authors.initials: F
authors.lastname: Lena
authors.forename: Sabrina
authors.initials: S
authors.lastname: Dispenza
authors.forename: Barbara
authors.initials: B
authors.lastname: Gandolfi
authors.forename: Ennio
authors.initials: E
authors.lastname: Iezzi
authors.forename: Giovanni
authors.initials: G
authors.lastname: Fabbrini
authors.forename: Alfredo
authors.initials: A
authors.lastname: Berardelli
mesh_terms: D000704:Analysis of Variance; D016022:Case-Control Studies; D003072:Cognition Disorders / Q000209:etiology / Q000628:therapy*; D046690:Deep Brain Stimulation / Q000379:methods*; D004192:Discrimination, Psychological / Q000187:drug effects / Q000502:physiology*; D015259:Dopamine Agents / Q000627:therapeutic use; D004569:Electroencephalography / Q000379:methods; D004576:Electromyography / Q000379:methods; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D009483:Neuropsychological Tests; D010300:Parkinson Disease / Q000150:complications / Q000628:therapy*; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology; D012684:Sensory Thresholds / Q000187:drug effects / Q000502:physiology; D012720:Severity of Illness Index; D013223:Statistics as Topic; D020531:Subthalamic Nucleus / Q000187:drug effects / Q000502:physiology*
chemical_list: D015259:Dopamine Agents