Odor Recognition Memory in Parkinson's Disease: A Systematic Review

Area of Science:

• Neuroscience
• Neurology
• Cognitive Science

Background:

• Olfactory impairment is a key non-motor symptom in Parkinson's disease (PD).
• Olfactory dysfunction in PD is linked to cognitive decline and mental health issues.
• Existing research primarily focuses on odor detection, discrimination, and identification, with limited attention to odor recognition memory (ORM).

Purpose of the Study:

• To systematically review and synthesize existing research on odor recognition memory (ORM) in Parkinson's disease (PD).
• To explore the potential of ORM tasks in detecting dementia among PD patients.
• To assess the diagnostic utility of ORM in differentiating PD from other neurodegenerative conditions like Alzheimer's disease (AD).

Main Methods:

• Systematic literature search of databases and reference lists.
• Inclusion of studies based on PICOS framework criteria.
• Quality assessment of included studies using the STROBE statement.
• Analysis of six small-sample studies with heterogeneous ORM tasks (odor recognition and odor matching).

Main Results:

• Parkinson's disease patients demonstrated significantly lower performance on both odor recognition and odor matching tasks compared to controls.
• The odor matching task showed a more pronounced deficit in PD patients.
• The odor recognition task revealed a significant difference between PD and AD patients, with PD patients performing better.

Conclusions:

• Limited data suggest that odor recognition tasks may aid in identifying Parkinson's disease dementia (PDD).
• Further research with larger sample sizes and standardized tasks is needed to validate the diagnostic potential of ORM in PD and PDD.
• Odor recognition memory shows promise as a biomarker for cognitive impairment in Parkinson's disease.