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
BACKGROUND: Cognitive deficits and reduced dopamine transporter (DAT) binding ratio have been reported in Parkinson's disease psychosis (PDP). However, it remains unclear whether DAT striatal binding ratio (SBR) may contribute to worsening cognitive performance in PDP. OBJECTIVES: We examined this using data from the Parkinson's Progression Markers Initiative. METHODS: I-FP-CIT-SPECT [(123) I-2β-carbomethoxy-3β-(4-iodophenyl)-N-(3-fluoropropyl) nortropane single photon emission computed tomography] imaging. We examined all cognitive measures assessed at each time point; sociodemographic characteristics, neuropsychiatric and PD-specific symptoms were entered as covariates of interest. FINDINGS: PDP patients had lower DAT SBR compared with PDnP patients (b=-0.092, p=0.035) over all time points, which remained significant after controlling for age, sex and ethnicity. PDP patients also reported worse trajectory of task performance on the Montreal Cognitive Assessment (MoCA) (b=-0.238, p=0.001) and symbol digit modality (b=-0.534, p=0.016) compared with PDnP patients. Declining performance in symbol digit modality (Group×Time×DAT SBR interaction, b=0.683, p=0.028) but not MoCA was differentially associated with the decline in DAT SBR over time. MoCA scores declined more in PDP compared with PDnP patients over all timepoints (Group×Time interaction, b=-0.284, p=0.016). CONCLUSIONS: Decline in striatal presynaptic dopamine function may specifically underlie longitudinal decline in performance in the symbol digit modality task that engages processing speed, associative learning and working memory in PD psychosis. Whether striatal presynaptic dopamine changes explain accelerated longitudinal decline in other cognitive domains in people with PDP remains to be tested.
Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.
How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| 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) | 0.000 | 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 teacher head, 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".