Decline in striatal binding ratio associated with accelerated decline in performance on Symbol Digit Modality but not MoCA in Parkinson’s disease psychosis
Bibliographic record
Abstract
Abstract Background Cognitive deficits have been reported in Parkinson’s Disease psychosis (PDP). Reduced dopamine transporter (DAT) binding ratio has also been associated with PDP. However, it remains unclear whether DAT striatal binding ratio (SBR) may contribute to worsening cognitive performance in PDP. Here, we examined this using data from the Parkinson’s Progression Markers Initiative study. Methods We analysed data from 408 PD patients, from baseline to year 4 follow up, and classified patients into PD with (PDP) and without psychosis (PDnP). DAT SBR was available from DaTSCAN imaging with 123 I-FP-CIT-SPECT. We examined all cognitive measures assessed at each time point, socio-demographics, neuropsychiatric and PD-specific symptoms were entered as covariates of interest. Results PDP patients had lower DAT SBR compared to PDnP patients (b=-0.092, p =0.035) which remained significant after controlling for age, sex, and ethnicity. PDP patients also reported worse trajectory of task performance on MoCA (b=-0.238, p =0.001) and Symbol Digit Modality (b=-0.534, p =0.016) across four years compared to PDnP patients. Worsening of MoCA scores in PDP was independent of DAT SBR decline (interaction group * study years, b=-0.284, p =0.016; three-way interaction group*study years*DAT SBR, b=0.127, p =0.225). However, declining performance in Symbol Digit Modality was significantly associated with the decline in DAT SBR (three-way interaction group*study years*DAT SBR, b=0.683, p =0.028). Conclusion Overall, longitudinal decline in striatal presynaptic dopamine function may underlie the greater longitudinal decline in performance in the symbol digit modality task that engages processing speed, associative learning and working memory in PD psychosis, whilst declining performance on MoCA seems unrelated to it. Whether striatal presynaptic dopamine changes explain accelerated longitudinal decline in other cognitive domains in people with PDP remains to be tested.
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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 | 0.001 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.001 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 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".