Early cognitive changes and nondementing behavioral abnormalities in Parkinson's disease

Area of Science:

• Neuroscience
• Neurology
• Cognitive Science

Background:

• Early cognitive changes in Parkinson's disease (PD) are often subtle.
• These changes are influenced by factors such as age, disease onset, medication, and motor symptoms.
• Despite influencing factors, specific early cognitive alterations are well-documented in PD.

Purpose of the Study:

• To highlight the occurrence of specific cognitive changes early in Parkinson's disease.
• To identify the nature of these early cognitive deficits.
• To underscore the need for prospective assessment of early behavioral changes and their prognostic implications.

Main Methods:

• The study reviews existing evidence on early cognitive changes in Parkinson's disease.
• It synthesizes findings on various cognitive domains, including olfaction, contrast sensitivity, executive function, memory, and visuospatial skills.
• It also considers the prevalence of depressive symptoms in early PD.

Main Results:

• Subtle changes in olfaction and contrast sensitivity are consistently observed early in PD.
• Executive function deficits are prominent and impact performance in memory and visuospatial tasks.
• Language processing deficits are infrequent in the early stages.
• Depressive symptoms are also common in early PD.

Conclusions:

• Specific cognitive changes, particularly in executive function, olfaction, and contrast sensitivity, are characteristic of early Parkinson's disease.
• These early cognitive and behavioral changes, including depression, require further prospective investigation to determine their prognostic value.