Language recovery following subthalamic nucleus stimulation in Parkinson's disease

Neuropsychological consequences of stimulation of the subthalamic nucleus for treatment of drug-resistant Parkinson's disease (PD) have been studied previously. However, no detailed investigations of linguistic function modifications have been carried out. We studied four consecutive patients with PD who underwent chronic bilateral stimulation of the subthalamic nuclei. Neuropsychological and linguistic evaluations were performed before and 2 weeks after surgery. Linguistic abilities were studied also 1 year after surgery with stimulators both off and on. Intraphrasal hesitation pauses, phonemic paraphasias and morpho-syntactic errors were significantly reduced and lexical retrieval improved with stimulation of the subthalamic nuclei. Implicit linguistic phenomena, mainly occurring within basal ganglia circuitry, benefited by recovery of functional equilibrium within basal nuclei and between overall basal ganglia circuitry and cerebral cortex.     

Alleviation of camptocormia by bilateral subthalamic nucleus stimulation in a patient with Parkinson's disease

Camptocormia, known also as "bent spine syndrome", is characterized by involuntary truncal flexion of the thoraco-lumbar spine that appears in the sitting or standing position. Although Parkinson's disease (PD) is the most frequent etiologic factor, this postural disorder responds poorly to levodopa or other medications. We report a PD patient in whom chronic bilateral subthalamic nucleus stimulation produced a striking alleviation of camptocormia.     

Bilateral subthalamic nucleus stimulation after bilateral pallidotomies in a patient with advanced Parkinson's disease

A 54-year-old man with advanced Parkinson's disease (PD) presented to our institution in early 2000. He had undergone a right pallidotomy in 1994, a left pallidotomy in 1996, and bilateral subthalamic nucleus (STN) electrode implants in 1999. The patient had cervical myelopathy for which he had undergone neck surgery in 1998. We used the Unified Parkinson's Disease Rating Scale (UPDRS) to evaluate motor performance in four states: combinations of stimulation OFF or ON and medication OFF or ON. There was no significant change in motor UPDRS scores with STN stimulation or with medications. Multiple attempts to optimize stimulation parameters and medication dosages did not result in significant and sustained improvement in activities of daily living or motor performance. To our knowledge, this is the first reported case of bilateral STN stimulation after bilateral pallidotomies. The presence of cervical myelopathy and the limited response to anti-Parkinson medications in this patient underscores the importance of patient selection for functional neurosurgery in PD.     

Bilateral subthalamic nucleus stimulation for Parkinson's disease

High frequency stimulation of the subthalamic nucleus (STN) is known to ameliorate the signs and symptoms of advanced Parkinson's disease. AIM: We studied the effect of high frequency STN stimulation in 23 patients. METHOD: Twenty-three patients suffering from severe Parkinson's disease (Stages III-V on Hoehn and Yahr scale) and, particularly bradykinesia, rigidity, and levodopa-induced dyskinesias underwent bilateral implantation of electrodes in the STN. Preoperative and postoperative assessments of these patients at 1, 3, 6 and 12 months follow-up, in "on" and "off" drug conditions, was carried out using Unified Parkinson's Disease Rating Scale, Hoehn and Yahr staging, England activities of daily living score and video recordings. RESULTS: After one year of electrical stimulation of the STN, the patients' scores for activities of daily living and motor examination scores (Unified Parkinson's Disease Rating Scale parts II and III) off medication improved by 62% and 61% respectively (p<0.0005). The subscores for the akinesia, rigidity, tremor and gait also improved. (p<0.0005). The average levodopa dose decreased from 813 mg to 359 mg. The cognitive functions remained unchanged. Two patients developed device-related complications and two patients experienced abnormal weight gain. CONCLUSION: Bilateral subthalamic nucleus stimulation is an effective treatment for advanced Parkinson's disease. It reduces the severity of "off" phase symptoms, improves the axial symptoms and reduces levodopa requirements. The reduction in the levodopa dose is useful in controlling drug-induced dyskinesias.     

Manic episode with psychotic symptoms induced by subthalamic nucleus stimulation in a patient with Parkinson's disease.

Deep brain stimulation of the subthalamic nucleus (STN-DBS) is an established therapy for Parkinson's disease (PD). A manic episode with psychotic symptoms induced by STN-DBS occurred in a previously psychiatrically healthy patient, focusing on the role of STN-DBS in influencing not only motor but also emotional behaviour.     

Ten Hertz thalamus stimulation increases tremor activity in the subthalamic nucleus in a patient with Parkinson's disease

OBJECTIVE: In patients with Parkinson's disease (PD) the effect of thalamic stimulation on tremor pathophysiology remains largely unclear. By recording local field potentials (LFPs) in the subthalamic nucleus (STN) while stimulating the nucleus ventralis intermedius thalami (VIM), information of the stimulation effects should be gained. METHODS: We had the unique opportunity to intraoperatively record LFPs of the STN in a patient with PD while stimulating the VIM. VIM electrodes had been implanted 9 years previously because of tremor. Due to worsening of clinical symptoms an implantation of STN electrodes had become necessary. RESULTS: High frequency stimulation in the VIM lowered the power of the tremor frequency band (4-7Hz) in the STN. In contrast, 10Hz VIM stimulation elevated the power of the tremor frequency band as well as STN-EMG coupling. CONCLUSIONS: The effect of high frequency stimulation may explain the improvement of tremor in patients who are treated with VIM deep brain stimulation. The power elevation during 10Hz stimulation suggests that the pathological cerebral and cerebral-muscular communication in PD is mainly driven at 10Hz. SIGNIFICANCE: The direct cerebral recordings support the view that a 10Hz network is a pathophysiological key mechanism in the generation of motor deficits in PD.     

Predictive factors of speech intelligibility following subthalamic nucleus stimulation in consecutive patients with Parkinson's disease

Speech changes after bilateral subthalamic nucleus deep brain stimulation (STN‐DBS) can be variable, with the majority of patients experiencing speech deterioration over time. The aim of this study was to describe the perceptual characteristics of speech following chronic STN‐DBS and to analyze clinical and surgical factors that could predict speech change. Fifty‐four consecutive patients (34 men; mean age ± standard deviation (SD), 58.8 ± 6.3 years; mean ± SD disease duration, 12.5 ± 4.7 years; mean ± SD levodopa equivalent, 1556 ± 671 mg/day; mean ± SD Unified Parkinson's Disease Rating Scale motor part (UPDRS‐III) off‐medication score, 48.1 ± 17.9 [range, 20‐89]; and mean ± SD UPDRS‐III on‐medication score, 12.4 ± 7.8 [range, 2‐31]) participated in this study. They were assessed before and at 1 year after surgery using the Assessment of Intelligibility for the Dysarthric Speech, the perceptual scale from Darley et al., and the UPDRS‐III. Speech intelligibility deteriorated on average by 14.4% (P = 0.0006) after 1 year of STN‐DBS when off‐medication and by 12.3% (P = 0.001) when on‐medication. The effect on speech was not linked to age at surgery, unlike the effect on motor outcome. The most significant predictive factors for deterioration of speech intelligibility when patients were off‐medication/on‐stimulation were lower preoperative speech intelligibility on‐medication, longer disease duration, and medially placed left hemisphere active electrode contact. Speech change after STN‐DBS is variable and multifactorial. Consistent preoperative speech evaluation would help inform patients about the possible effects of surgery. Appropriate consideration of speech deficits might assist surgical targeting, particularly of the left electrode. © 2014 International Parkinson and Movement Disorder Society     

Bilateral subthalamic nucleus stimulation improves balance control in Parkinson's disease

BACKGROUND: Parkinson's disease (PD), the most common basal ganglia degenerative disease, affects balance control, especially when patients change balance strategy during postural tasks. Bilateral chronic stimulation of the subthalamic nucleus (STN) is therapeutically useful in advanced PD, and reduces the motor signs of patients. Nevertheless, the effects of STN stimulation on postural control are still debatable. AIMS: To assess the impact of bilateral STN stimulation on balance control in PD and to determine how basal ganglia related sensorimotor modifications act on neurosensorial organisation of balance and motor postural programming. METHODS: Twelve subjects aged 45-70 years underwent unified Parkinson's disease rating scale motor (part III) clinical tests, static and dynamic posturography, including sensory organisation and adaptation tests, shortly before and six months after bilateral implantation of electrodes into the STN. RESULTS: The postoperative static test showed an improvement in postural control precision both in eyes open and eyes closed conditions. The dynamic test highlighted the decreased number of falls and the ability of the patients to develop more appropriate sensorimotor strategies when stimulated. The sensory organisation test showed an improvement of equilibrium score and, thus, a better resolution of sensorial conflicts. CONCLUSIONS: STN stimulation allowed a reduction in rigidity and therefore an improvement in the ability to use muscular proprioception as reliable information, resulting in vestibulo-proprioceptive conflict suppression. STN stimulation has a synergistic effect with levodopa for postural control. Accordingly, non-dopaminergic pathways could be involved in postural regulation and STN stimulation may influence the functioning of these pathways.     

Long-term follow up of subthalamic nucleus stimulation in Parkinson's disease

Twenty-two patients with PD received bilateral implants for high frequency stimulation of the subthalamic nucleus. The patients were treated for more than 1 year (up to 36 months). At the last visit, the Unified Parkinson Disease Rating Scale (UPDRS) motor score without medication improved by 50.2% (p < 0.001) and the UPDRS activities of daily living score improved by 68.4% (p < 0.001). The most common long-lasting adverse events were hypophonia and dysarthria; transient events were increased sexuality and mania. The surgical procedure induced transient intraoperative psychosis in seven patients.     

Contrast sensitivity in Parkinson's disease patients with subthalamic nucleus deep brain stimulation

This study examined whether deep brain stimulation (DBS) would affect the contrast sensitivity (CS) curve in patients with PD. CS was tested in 12 nondemented PD patients treated with bilateral subthalamic nucleus DBS on and off stimulation and medications. Neither stimulation condition (on vs. off) nor medications altered CS performance in this group of patients. However, collapsed across conditions, patients with bipolar stimulation in this study had significantly poorer CS at higher spatial frequencies (12 and 18 cycles per degree) than patients with monopolar stimulation. This suggests that CS deficits in PD may possibly be influenced by DBS polarity and merits further study. © 2009 Movement Disorder Society     

Predict initial subthalamic nucleus stimulation outcome in Parkinson's disease with brain morphology

AimSubthalamic nucleus deep brain stimulation (STN‐DBS) has been reported to be effective in treating motor symptoms in Parkinson''s disease (PD), which may be attributed to changes in the brain network. However, the association between brain morphology and initial STN‐DBS efficacy, as well as the performance of prediction using neuroimaging, has not been well illustrated. Therefore, we aim to investigate these issues.MethodsIn the present study, 94 PD patients underwent bilateral STN‐DBS, and the initial stimulation efficacy was evaluated. Brain morphology was examined by magnetic resonance imaging (MRI). The volume of tissue activated in the motor STN was measured with MRI and computed tomography. The prediction of stimulation efficacy was achieved with a support vector machine, using brain morphology and other features, after feature selection and hyperparameter optimization.ResultsA higher stimulation efficacy was correlated with a thicker right precentral cortex. No association with subcortical gray or white matter volumes was observed. These morphological features could estimate the individual stimulation response with an r value of 0.5678, an R ² of 0.3224, and an average error of 11.4%. The permutation test suggested these predictions were not based on chance.ConclusionOur results indicate that changes in morphology are associated with the initial stimulation motor response and could be used to predict individual initial stimulation‐related motor responses.     

Chronic subthalamic nucleus stimulation reduces medication requirements in Parkinson's disease.

OBJECTIVE: To reduce antiparkinsonian medication in parkinsonian patients with bilateral high frequency subthalamic nucleus (STN) stimulation. BACKGROUND: Parkinsonian syndromes are characterized by hyperactivity of the STN. Preliminary data indicate that functional inactivation of the STN may reduce the requirement for dopaminergic therapy in PD. METHODS: Bilateral quadripolar leads were implanted stereotactically in the STN of seven patients with advanced PD (mean age, 57.4 years; mean disease duration, 15.4 years). High-frequency stimulation was applied for 24 hours a day. Following implantation, antiparkinsonian medication was reduced to the minimum possible and stimulation was gradually increased. The patients were evaluated in the practically defined "off" and "on" conditions using the Unified Parkinson's Disease Rating Scale (UPDRS) and the Schwab & England scale. The average follow-up was 16.3+/-7.6 months. A battery of neuropsychological tests was applied before and 9 months after the implant. RESULTS: Parkinsonian features improved in all patients--the greatest change seen in rigidity, then tremor, followed by bradykinesia. Compared with the presurgical condition, off-drug UPDRS motor scores improved by 41.9% on the last visit (p = 0.0002), UPDRS activities of daily living (ADL) scores improved by 52.2% (p = 0.0002), and the Schwab & England scale score improved by 213% (p = 0.0002). The levodopa-equivalent daily dose was reduced by 65%. Night sleep improved in all patients due to increased mobility at night, and in five patients insomnia was resolved. All patients gained weight after surgery and their appetite increased. The mean weight gain at the last follow-up was 13% compared with before surgery. During the last visit, the stimulation amplitude was 2.9+/-0.5 V and the total energy delivered per patient averaged 2.7+/-1.4 W x10(-6). The results of patient self-assessment scales indicated a marked improvement in five patients and a moderate improvement in the other two. The neuropsychological data showed no changes. Side effects were mild and tolerable. In all cases, a tradeoff between the optimal voltage and the severity of side effects made it possible to control parkinsonian signs effectively. The most marked side effects directly related to STN stimulation consisted of ballistic or choreic dyskinesias of the neck and the limbs elicited by contralateral STN stimulation above a given threshold voltage, which varied depending on the individual. CONCLUSIONS: Parkinsonian signs can be controlled by bilateral high-frequency STN stimulation. The procedure is well tolerated. On-state dyskinesias were greatly reduced, probably due to the reduction of total antiparkinsonian medication. Bilateral high-frequency STN stimulation compensated for drug reduction and elicited dyskinesias, which differ from those observed following dopaminergic medication. ADL improved significantly, suggesting that some motor tasks performed during everyday chores, and that are not taken into account in the UPDRS motor score, also improved.     

Effect of subthalamic nucleus stimulation on levodopa-induced dyskinesia in Parkinson's disease

Article abstract-The authors studied the effect of bilateral subthalamic nucleus stimulation on levodopa-induced dyskinesias in 24 consecutive parkinsonian patients with disabling dyskinesias. The improvement in the three subtypes of levodopa-induced dyskinesias was significant from the third postoperative month and was mainly due to the decrease in the daily dose of levodopa allowed by the stimulation-induced improvement in the motor score.