Mild cognitive dysfunction in hereditary spastic paraplegia 4 disease related to fluorodesoxyglucose cerebral positron emission tomography
Bibliographic record
Abstract
Abstract Autosomal dominant spastic paraplegia type 4 (SPG4, SPAST gene) is commonly described as a pure phenotype, with progressive spastic weakness of the lower limbs. Some cognitive disorders have been reported but remain difficult to characterize. Brain flurodesoxyglucose (18F-FDG) PET is a sensitive biomarker of glycolytic metabolism and shows loss of neuronal activity. Our objective was to describe the cognitive impairment of SPG4 patients, supported by brain 18F-FDG PET, to characterize the cognitive pattern and its localization. Twenty subjects from the Grand Est region, with a pathogenic variant in the SPAST gene, were included. Each patient had to undergo a neuropsychological assessment, a brain 18F-FDG PET scan, and a SPATAX-EuroSpa clinical assessment, including the Spastic Paraplegia Rating Scale (SPRS). Brain 18F-FDG PET was analyzed semiquantitatively after comparison with age and sex-matched control subjects. The study population was 65% (13/20) female, with an average age of 50 years (19–75 years). The median SPRS was 15/52 (12–45). Forty-six percent (7/15) of patients had a deficient Montreal Cognitive Assessment (MoCA) score (score <26) without any severe impairment (score <10). Assessments with a pathological score of <1.65 standard deviations or at the 5th percentile included verbal episodic memory in 16-item Free and Cued Recall Test (16-FCRT; 63%, 10/16), facial emotion recognition (56%, 9/16), and executive functions (Trail Making Test A and B; 47%, 7/15; the Stroop; 47%, 7/15; digit span of Weschler Adult Intelligence Scale 4; 38%, 6/16). Compared with those of control subjects, 18-FDG PET images of the brains of SPG4 subjects revealed frontotemporal and precuneus hypometabolism, principally in the prefrontal cortex, which was mainly mesial (P voxel value <0.001, corrected for the size of the familywise error (FWE) cluster, k = 1464). Frontal hypometabolism was correlated with age at onset (k = −0.475, P = 0.046) and the time to perform the Trail Making Test B test (k = −0.597, P = 0.019). Here, we describe a mild cognitive disorder clinically in SPG4 patients, associated with an hypometabolism on 18F-FDG PET imaging, which mainly corresponded to frontotemporal localization. Mild cognitive dysfunction should be screened in SPG4, as it can have a significant impact on socioprofessional life. Brain 18F-FDG PET, combined with neuropsychological assessment appears to be a good screening and follow-up examination for cognitive disorders.
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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 | 0.000 | 0.004 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.002 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.000 | 0.001 |
| 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".