Neuropsychological consequences of chronic bilateral stimulation of the subthalamic nucleus in Parkinson's disease
Bibliographic record
Abstract
The aim of this study was to examine possible neuropsychological changes in patients with advanced idiopathic Parkinson's disease treated with bilateral deep brain stimulation (DBS) of the subthalamic nucleus (STN). Eleven patients (age = 67 +/- 8 years, years with Parkinson's disease = 15 +/- 3, verbal IQ = 114 +/- 12) were evaluated (in their best 'on state') with tests assessing processes reliant on the functional integrity of frontal striatal circuitry, prior to the procedure (n = 11), at 3-6 months (n = 11) and at 9-12 months (n =10) post-operatively. Six of these patients were older than 69 years. Despite clinical motor benefits at 3-6 months post-operative, significant declines were noted in working memory, speed of mental processing, bimanual motor speed and co-ordination, set switching, phonemic fluency, long-term consolidation of verbal material and the encoding of visuospatial material. Declines were more consistently observed in patients who were older than 69 years, leading to a mental state comparable with progressive supranuclear palsy. 'Frontal' behavioural dyscontrol without the benefit of insight was also reported by half (three of six) of the caregivers of the elderly subgroup. At 9-12 months postoperative, only learning based on multiple trials had recovered. Tasks reliant on the integrity of frontal striatal circuitry either did not recover or gradually worsened over time. Bilateral STN DBS can have a negative impact on various aspects of frontal executive functioning, especially in patients older than 69 years. Future studies will evaluate a larger group of patients and examine the possible reversibility of these effects by turning the DBS off.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".