SynthesisAgeing research reviews2021
Olfactory dysfunction in aging and neurodegenerative diseases.
Synthesis in Ageing research reviews, 2021. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT07445945 (Physiological Effect of Non-invasive Photobiomodulation on Cognition and Mood in Older Adults With Subjective Cognitive Impairment), which is not on this map. Cited by 142 papers, 4 of them syntheses that pooled it.
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.
Physiological Effect of Non-invasive Photobiomodulation on Cognition and Mood in Older Adults With Subjective Cognitive Impairment
Who cites it
142 citing papers in PubMed, 4 syntheses or guidelines pooled it.
- Neurobiological mechanisms of olfactory dysfunction: a ten-year bibliometric and visualization analysis.Frontiers in medicine · 2026Pooled it
- The Utility of Olfactory Testing to Discriminate Parkinson's Disease From Diagnostic Mimics: A Systematic Review and Meta-Analysis.European journal of neurology · 2026Pooled it
- Obesity, Olfaction and Cognition: A Systematic Review.Current obesity reports · 2025Pooled it
- Disparity of smell tests in Alzheimer's disease and other neurodegenerative disorders: a systematic review and meta-analysis.Frontiers in aging neuroscience · 2023Pooled it
- Article
- Cellular redox status is linked to olfactory alterations in cognitive decline.Redox biology · 2026Article
- Recovery of Parosmia Preferentially Influences Longitudinal Improvement of Quality of Life in C19OD.International forum of allergy & rhinology · 2026Article
- Canine "Sniffin' Sticks" enable behavioural olfactometry to complement neurological examination in dogs.Scientific reports · 2026Article
- Sensory decline in aging and neurodegeneration: A mitochondrial perspective.Pharmacological research · 2026Review
- The dynamic impairment of synaptic transmission in the PCx-IL engram circuit contributes to early olfactory memory decline in Alzheimer's disease.Molecular psychiatry · 2026Article
- Neuroinflammation in Alzheimer's and Parkinson's diseases: pathogenic mechanisms and therapeutic strategies.Translational neurodegeneration · 2026Review
- Olfactory impairment associated with cognitive decline: findings from cognitive domain assessments among older adults in West Jakarta, Indonesia.BMC geriatrics · 2026Article
- Exploring Olfactory Bulb Volume and Its Shrinkage in Aging and Neurodegeneration: A Systematic Review and Meta-Analysis of Observational Studies.The Indian journal of radiology & imaging · 2026Article
- Reliability, repeatability, and age associations of the dogSIT (dog Smell Interaction Test) battery in untrained companion dogs (Canis lupus familiaris).Scientific reports · 2026Article
- Olfaction and muscle strength in older adults: a longitudinal study.The journals of gerontology. Series A, Biological sciences and medical sciences · 2026Article
- Subjective and objective olfactory dysfunction and its screening value in patients with subjective cognitive decline, mild cognitive impairment, and Alzheimer's dementia.Neuropsychiatrie : Klinik, Diagnostik, Therapie und Rehabilitation : Organ der Gesellschaft Osterreichischer Nervenarzte und Psychiater · 2026Article
- RBAD: The first database dedicated alterations of blood RNA in individuals with Alzheimer's disease and their clinical relevance.Neural regeneration research · 2026Article
- Persistent Olfactory Dysfunction Three Years After COVID-19: A Multicenter Observational Study.Pathogens (Basel, Switzerland) · 2026Observational
- Use of Artificial Intelligence for the Early Detection and Prediction of Alzheimer's Disease.Cureus · 2026Review
- The Indian Smell Identification Test for Parkinson's Disease: Limitations of Binary Scoring and Proposal of a Modified Graded Approach.Annals of Indian Academy of Neurology · 2026Article
82 more citing papers are in PubMed but not listed here.
Corrections and comments
PubMed lists nothing against this paper. Absence here is not a guarantee, only a check that was made.
Authors and funding
6 authors.
Funding
Abstract
Alterations in olfactory functions are proposed to be early biomarkers for neurodegeneration. Many neurodegenerative diseases are age-related, including two of the most common, Parkinson's disease (PD) and Alzheimer's disease (AD). The establishment of biomarkers that promote early risk identification is critical for the implementation of early treatment to postpone or avert pathological development. Olfactory dysfunction (OD) is seen in 90% of early-stage PD patients and 85% of patients with early-stage AD, which makes it an attractive biomarker for early diagnosis of these diseases. Here, we systematically review widely applied smelling tests available for humans as well as olfaction assessments performed in some animal models and the relationships between OD and normal aging, PD, AD, and other conditions. The utility of OD as a biomarker for neurodegenerative disease diagnosis and future research directions are also discussed.
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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.