Relation between Olfactory Dysfunction and Episodic Verbal Memory in Early Parkinson's Disease.

Area of Science:

• Neurology
• Neuroscience

Background:

• Olfactory dysfunction is a common early symptom of idiopathic Parkinson's disease (IPD).
• Emerging evidence suggests a link between olfactory dysfunction and cognitive decline in IPD patients.

Purpose of the Study:

• To investigate the relationship between olfactory dysfunction and cognitive impairments in early-stage IPD.
• To explore potential correlations between olfactory deficits and specific cognitive functions.

Main Methods:

• Included 28 early-stage IPD patients (Hoehn-Yahr stages 1-2) and 19 healthy controls.
• Assessed olfactory function using the University of Pennsylvania Smell Identification Test (UPSIT).
• Evaluated cognitive functions via clock drawing, Stroop, verbal fluency, Benton face recognition, Benton line judgment, and Auditory Verbal Learning Test.

Main Results:

• IPD patients exhibited significantly lower UPSIT scores compared to controls (p=.018).
• Patients showed significant deficits in Stroop and Benton Line Judgment Orientation Test (BLOT) (p=.003, p=.002).
• Negative correlations were found between UPSIT scores and Stroop test (time and errors), and a positive correlation with Auditory Verbal Learning Test (SBST) long-term memory scores in patients.

Conclusions:

• Early IPD is associated with mild cognitive impairments in visuospatial and executive functions.
• A distinct pattern of memory and frontal function impairment, correlated with hyposmia, was observed in IPD patients.
• This suggests a potential subgroup of IPD characterized by early-stage olfactory dysfunction and impaired episodic verbal memory.