ArticleBMJ neurology open2026
Complementary biomarkers or conflicting signals? DaT SPECT and synuclein skin biopsy in parkinsonian syndromes.
Article in BMJ neurology open, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Not yet cited in PubMed.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
0 citing papers in PubMed.
No citing paper in PubMed yet.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
5 authors.
Funding
No grant is acknowledged in the PubMed record.
Abstract
Introduction: Diagnosing Parkinson's disease (PD) and related synucleinopathies in patients with early or atypical features remains challenging. Dopamine transporter single-photon emission CT (DaT SPECT) imaging and phosphorylated alpha-synuclein (p-Syn) skin biopsy are increasingly used, but their concordance and combined value in diagnostically uncertain, real-world patients are unknown. We evaluated whether these two biomarkers provide complementary rather than redundant diagnostic information. Methods: We retrospectively analysed patients evaluated at a tertiary movement disorders centre (January 2022-March 2025) who presented with parkinsonism or tremor not meeting established criteria for PD, multiple system atrophy or dementia with Lewy bodies. 86 patients underwent p-Syn skin biopsy; 52 also underwent DaT SPECT. Using the treating neurologist's final clinical diagnosis as the reference standard, we calculated sensitivity, specificity, predictive values and concordance for each test and for combined ('either-positive') testing and compared clinical features between concordant and discordant groups. Results: DaT SPECT and p-Syn biopsy showed similar sensitivity (79.0% and 79.0%) and specificity (74.0% and 81.0%) for synucleinopathy. Combined testing increased sensitivity to 95.6% but reduced specificity to 59.9%. Results were discordant in 30.8% of dual-tested patients; +DaT/-p-Syn patients more often reported hyposmia, whereas -DaT/+p Syn patients more often reported REM sleep behaviour disorder. Almost half of discordant cases ultimately met criteria for idiopathic PD. Conclusions: DaT SPECT and p-Syn skin biopsy provide complementary, not redundant, diagnostic information. The high discordance, with eventual PD diagnosis in many cases, is consistent with the dual-origin (brain-first vs body-first) model of alpha-synuclein propagation. Both are best used as rule-in tests in early or diagnostically uncertain disease, where a negative result does not exclude a synucleinopathy; in advanced disease meeting full clinical criteria, they may have greater rule-out value. Combined testing improves early detection at a cost to specificity, with implications for trial enrolment and for interpreting biomarkers alongside symptom evolution.
Indexed as
Identifiers
What OpenQuestion holds
Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.