Deep brain stimulation of the subthalamic nucleus improves intrinsic alertness in Parkinson's disease.

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is a treatment option for patients with Parkinson's disease (PD) in the advanced stage. Besides motor improvement, DBS of the STN may also modulate cognitive and attentional functions of the basal ganglia. In our study, 13 patients with PD and bilateral DBS of the STN were assessed with DBS switched on and off by the use of a wide range of neuropsychological tasks. This included reasoning, cognitive flexibility, phonemic and semantic word fluency, verbal and nonverbal short-term memory, learning, delayed verbal memory recall, and stimulus-response incompatibility. Special emphasis was put on basic attentional functions, in particular intrinsic and phasic alertness as well as visual search. DBS significantly improved intrinsic alertness, whereas phasic alertness and other neuropsychological domains were not affected. Additionally, the effects on intrinsic alertness were independent of motor improvements by DBS. The findings suggest that DBS modulates the fronto-parietal network of alertness.

Fimm B ，Heber IA ，Coenen VA ，Fromm C ，Noth J ，Kronenbuerger M ... -  《-》

Deep brain stimulation and cognitive functions in Parkinson's disease: A three-year controlled study.

There is debate over the cognitive and behavioral effects of deep brain stimulation (DBS) of the subthalamic nucleus (STN) in advanced Parkinson's disease (PD). To evaluate these effects, we performed a prospective, naturalistic controlled, 3-year follow-up study. A total of 65 PD patients were enrolled, of whom 32 underwent STN-DBS (PD-DBS) and 33, even though eligible for this treatment, declined surgery and chose other therapeutic procedures (PD-control). Motor and neuropsychological functions were assessed in all the subjects at baseline (T0) and 36 months (T36). The PD-DBS patients were also evaluated at 1, 6, 12, and 24 months after surgery (T1, T6, T12, and T24). At T1, compared with T0, the PD-DBS patients recorded worse logical executive function task and verbal fluency (FAS) scores, whereas their performance of memory tasks remained stable. At T12, their cognitive profile had returned within the pre-DBS range, thereafter remaining stable until T36. FAS scores at T36 were significantly worse in the PD-DBS compared with the PD-control patients. This is the first long-term naturalistic controlled study of cognitive functions in PD patients submitted to STN-DBS. Our results confirm previous reports of a worsening of verbal fluency after DBS, but show that STN-DBS seems to be relatively safe from a cognitive standpoint, as the short-term worsening of frontal-executive functions was found to be transient.

Zangaglia R ，Pacchetti C ，Pasotti C ，Mancini F ，Servello D ，Sinforiani E ，Cristina S ，Sassi M ，Nappi G ... -  《-》

The effects of bilateral subthalamic nucleus deep brain stimulation (STN DBS) on cognition in Parkinson disease.

Heo JH ，Lee KM ，Paek SH ，Kim MJ ，Lee JY ，Kim JY ，Cho SY ，Lim YH ，Kim MR ，Jeong SY ，Jeon BS ... -  《JOURNAL OF THE NEUROLOGICAL SCIENCES》

Acute psychotropic effects of bilateral subthalamic nucleus stimulation and levodopa in Parkinson's disease.

High-frequency deep brain stimulation (DBS) of the subthalamic nucleus (STN) improves the motor symptoms of Parkinson's disease (PD). Opposite changes in mood, such as mania or depression, have been reported after surgery, but it is not known whether these side effects are specifically related to STN DBS. To learn whether STN DBS also influences the limbic loop, we investigated acute subjective psychotropic effects related to levodopa or bilateral STN DBS. After a median postoperative follow-up of 12 months, 50 PD patients completed the Addiction Research Center Inventory (ARCI), assessing subjective psychotropic effects in four conditions: off-drug/on-stimulation; off-drug/off-stimulation; on-drug/off-stimulation; and on-drug/on-stimulation. Both levodopa and STN DBS improved all the ARCI subscales, indicating subjective feelings of well being, euphoria, increase in motivation, and decrease in fatigue, anxiety, and tension. A suprathreshold dose of levodopa was significantly more effective than STN DBS, using the same electrical parameters as for chronic stimulation, on four of the five ARCI subscales. We concluded that 1) both STN DBS and levodopa have synergistic acute beneficial psychotropic effects in PD, 2) the psychotropic effects of both treatments need to be considered in the long-term management of chronic STN DBS, and 3) the results indicate an involvement of the limbic STN in mood disorders of PD.

Funkiewiez A ，Ardouin C ，Krack P ，Fraix V ，Van Blercom N ，Xie J ，Moro E ，Benabid AL ，Pollak P ... -  《-》

Two-year follow-up on the effect of unilateral subthalamic deep brain stimulation in highly asymmetric Parkinson's disease.

Although bilateral subthalamic deep brain stimulation (STN DBS) provides greater relief from the symptoms of Parkinson's disease (PD) than unilateral STN DBS, it has been suggested that unilateral STN DBS may be a reasonable treatment option in selected patients, especially those with highly asymmetric PD. In previous studies on the effect of unilateral STN DBS, the asymmetry of PD symptoms was not prominent and the mean follow-up durations were only 3 to 12 months. In this study, we report our findings in a series of 8 patients with highly asymmetric PD who were treated with unilateral STN DBS and were followed for 24 months. Serial changes in Unified Parkinson's Disease Rating Scale (UPDRS) motor score and subscores in the ipsilateral, contralateral, and axial body parts were analyzed. Unilateral STN DBS improved the UPDRS motor score and the contralateral subscore in the on-medication state for 5 nonfluctuating patients and in the off-medication state for 3 fluctuating patients. However, the ipsilateral subscore progressively worsened and reversed asymmetry became difficult to manage, which led to compromised medication and stimulator adjustment. At 24 months, all the patients were considering the second-side surgery. Our results suggest that bilateral STN DBS should be considered even in highly asymmetric PD.

Kim HJ ，Paek SH ，Kim JY ，Lee JY ，Lim YH ，Kim DG ，Jeon BS ... -  《-》