Standing middle cerebral artery velocity predict cognitive performance on working memory tasks in adults with varying levels of cognitive abilities
Notice bibliographique
Résumé
The pathophysiology of dementia is multifactorial and reduced cerebral blood flow (CBF) is a predictor of cognitive impairment. The majority of research on CBF and dementia has been completed in the supine position, however during upright-posture the vascular system must counter gravitational forces and the redistribution of blood volume to the working muscles to maintain CBF. Determine if diastolic middle cerebral artery velocity (MCAdv) during standing is associated with lower performance on a working memory task (WMT, 1-back or 2-back) in older adults. Fifty-three participants (73±6yrs, 17-females: 14 cognitively intact, 30 mild cognitive impairment, 9 dementia) were analyzed. MCAdv profiles the lowest level of flow within a cardiac cycle. Beat-by-beat MCAdv (transcranial Doppler ultrasound) and mean arterial pressure (MAP, plethysmography) were averaged for 30-sec during supine-rest and standing (figure 1). K-means algorithms identified three homogeneous groups (increased-MCAdv, maintained-MCAdv, and reduced-MCAdv) from standing MCAdv (figure 2). Participants completed a 90-second WMT and a performance-based signal detection variable was calculated [sensitivity-A’=0.5+((hit rate−false alarm rate) × (1+hit rate−false alarm rate))/(4 × hit rate × (1−false alarm rate))], and a speed versus accuracy exchange was calculated [sensitivity-A’ score=100xsensitivity-A’/target reaction time(ms)x100]. ANCOVA (covariate: age), and post-hoc analyses were completed on standing MCAdv and WMT. Multiple linear regressions were completed for WMT with age and either MAP or MCAdv (supine and standing), and simple linear regressions were also completed. Significance was set to p≤0.05. The reduced-MCAdv group had lower WMT scores (p<0.02) compared to the increased- or maintained-MCAdv groups (figure 2). There was a linear correlation between standing-MCAdv and WMT which was not observed while supine (figure 3). Similarly, regression modelling predicted WMT [F(3,49)=2.533, p=0.068, R2=0.134] with standing-MCAdv, supine-MCAdv, and age, and only standing-MCAdv was a significant predictor variable (p=0.013). This relationship was unique to MCAdv and was not observed with MAP. Decreased MCAdv when standing, demonstrates a linear relationship with reduced working memory in older adults. This was not observed in the supine position and was not present with measures of peripheral arterial flow (MAP), indicating a unique relationship between dynamic measures of MCAdv and memory tasks, which was not observed at supine rest or in MAP.
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Comment cette classification a été obtenuedéplier
Prédiction distillée sur la base complète
Imitation des enseignantsNi prévalence calibrée, ni vérité terrain. Validation humaine à venir. Apprise à partir de 10 348 étiquettes directes de Codex et de 10 348 étiquettes directes de Gemma. Le mode candidate est l'union des têtes enseignantes seuillées; le consensus est leur intersection. Ces sorties portent le statut machine_predicted_unvalidated et ne sont ni des étiquettes humaines ni des étiquettes directes de modèles de pointe.
Scores Codex et Gemma par catégorie
| Catégorie | Codex | Gemma |
|---|---|---|
| Métarecherche | 0,000 | 0,000 |
| Méta-épidémiologie (sens strict) | 0,000 | 0,000 |
| Méta-épidémiologie (sens large) | 0,000 | 0,000 |
| Bibliométrie | 0,000 | 0,000 |
| Études des sciences et des technologies | 0,000 | 0,000 |
| Communication savante | 0,000 | 0,000 |
| Science ouverte | 0,000 | 0,000 |
| Intégrité de la recherche | 0,000 | 0,000 |
| Charge utile insuffisante (le modèle a refusé de juger) | 0,000 | 0,000 |
Scores machine (provisoires)
Les deux têtes enseignantes du modèle étudiant, lues sur ce travail. Un score ordonne la base pour la relecture; il n'affirme jamais une catégorie, et le statut de validation accompagne chaque rangée tel quel.
Scores de référence d'un modèle non mature (critères de maturité non atteints, 7 itérations). Un score ordonne; il n'affirme jamais une catégorie.
score_only:v0-immature-baseline · tel quel depuis la passe de notation : score_only signifie que le nombre peut ordonner les travaux, et qu'aucune étiquette de catégorie n'en découleClassification
machine, non validéePrédiction automatique; un appel candidat d’une seule tête enseignante, pas un consensus.
Le détail, modèle par modèle et score par score, se trouve en fin de page sous « Comment cette classification a été obtenue ».