Biais de la perception de la verticale dans la maladie de Parkinson : revue de la littérature et méta-analyse. a systematic review and meta-analysis
Bibliographic record
Abstract
Introduction. Postural disorders are frequent and represent a major source of disability in Parkinson’s disease (PD). Their mechanisms remain to be clarified. The possibility of a bias in the construction of the internal model of verticality is emerging. The number of studies investigating the perception of the vertical in PD has recently much increased. Time has come to synthetize them. This was the objective of this systematic review and meta-analysis. Methodology. We systematically searched in Medline and Cochrane databases from 1960 to December 2021 using the terms "Parkinson Disease", "verticality perception" and their derivatives. We followed the PRISMA and Cochrane recommendations. Eligibility for inclusion, data extraction and study quality (Newcastle-Ottawa scale, NOS) were assessed by two investigators (AT, CP), who followed a standardized protocol. We are preparing the Prospero Registration, and will update the study at due time. We analyzed frequency and magnitude of tilts found in verticality perception by random-effects models meta-analysis. We respected the definition of abnormal tilts given in each study. Results. We identified 17 studies (618 individuals; mean age 66.3 years; 55% male; mean disease duration 8.9 years), the majority of which were published between 2010 and 2020. The quality of the studies was adequate, with a mean NOS score of 7.4 (SD=1.14). Only the visual vertical (VV) could be investigated through a meta-analysis, because of too few studies with small sample size on haptic (n=2) and postural verticals (n=4). For VV, the pooled frequency of abnormal tilts was high: 45% (95% confidence interval [CI] [20; 70], I²=94.5%) in all individuals with PD regardless of it severity and duration of disease course, reaching 62% (95% CI [19; 106], I²=92%) in individuals with PISA syndrome (PS). In all individuals tested, the pooled magnitude of VV tilts was 0.2° (95% CI [-0.57; 0.89], I2=0%) in signed values, and 3.6° (95% CI [1.83; 5.34], I2=52.2%) in absolute values. In individuals in whom VV was abnormally tilted, the pooled magnitude of VV tilts was 5.3° in absolute value (95% CI [3.4; 7.3], I²=52.2%). Few studies investigated the concordance between VV tilts and the side where basal ganglia were predominately altered, as well as the concordance with a body tilt if any (PS). When analyzed this concordance is weak. Conclusion. This is the first systematic review of verticality perception in PD, conducted on 17 studies gathering 618 individuals. We show that VV is often abnormally tilted, but with of a mild magnitude. Because the VV investigates the vestibular graviception, these findings might mean that the vestibular information is frequently impaired in PD, but with a moderate asymmetry between left and right basal ganglia. However, directional concordances for VV and PD or PS tilts were not well analyzed, and when analyzed this concordance was weak. These findings suggest the coexistence of two mechanisms. Most abnormal VV tilts seem to be the consequence of the PS on the perception of the vertical, altered by trunk deformity or misorientation with respect to gravity. In some cases, VV tilts reflect an impaired vestibular graviception. In the future, studies will have to test several modalities of verticality perception, especially visual and postural, on large series, and scrutinize concordances in sides of tilts, body, and verticality perception.
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 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 | 0.048 | 0.093 |
| Meta-epidemiology (narrow) | 0.004 | 0.002 |
| Meta-epidemiology (broad) | 0.026 | 0.052 |
| Bibliometrics | 0.013 | 0.012 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.006 | 0.004 |
| Open science | 0.003 | 0.003 |
| Research integrity | 0.004 | 0.002 |
| Insufficient payload (model declined to judge) | 0.004 | 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".