Age and severity of nigrostriatal damage at onset of Parkinson's disease
Bibliographic record
Abstract
Abstract The clinical evolution of Parkinson's disease (PD) is known to be partly dependent on the age of onset. For example, motor complications associated with chronic dopaminomimetic treatment occur more often in younger patients. However, few attempts have been made to characterize the functional pathological differences underlying this age effect. We investigated the relationship between age and severity of nigrostriatal damage at onset of PD. Twenty patients with early PD (symptom duration ≤5 years) with onset before age 50 (n = 10) and with onset after age 50 (n = 10) were studied. The two groups were compared with respect to severity of nigrostriatal damage as evaluated by positron emission tomography (PET) scanning with 6‐[18F]fluoro‐L‐dopa ([18F]‐dopa), (±)‐α‐[11C]dihydrotetrabenazine ([11C]DTBZ), and d‐threo‐[11C]methylphenidate ([11C]MP). We found no significant differences between younger‐ and older‐onset PD patients with regard to any of the three presynaptic markers. For putamen, the P‐values corresponding to the different PET measurements ranged from P = 0.34 ([18F]‐dopa) to P = 0.79 ([11C]DTBZ). However, after adjusting for treatment and PD duration, regression analysis showed that [18F]‐dopa uptake correlated positively with age of onset (r = 0.59; P = 0.010). No correlation was found between [11C]DTBZ and [11C]MP binding potentials and age of onset (P = 0.26 and P = 0.90, respectively). These data suggest that age‐of‐onset‐dependent differences in clinical evolution are not likely to reflect early differences in nigrostriatal pathology in PD. Age‐related differences in [18F]‐dopa uptake may be related to changes in dopamine turnover. Synapse 47:152–158, 2003. © 2002 Wiley‐Liss, Inc.
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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 | 0.002 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.001 | 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".