Dual-task performance in early stage dementia: differential effects for automatized and effortful processing

Area of Science:

• Cognitive Neuroscience
• Neurology

Background:

• Alzheimer's disease (AD) is a neurodegenerative disorder characterized by progressive cognitive decline.
• Attentional deficits are a common early symptom of AD, impacting daily functioning.

Purpose of the Study:

• To investigate attentional processing in early-stage Alzheimer's disease (AD) compared to normal cognition (NC).
• To examine how task automatization influences dual-task performance in individuals with early AD.

Main Methods:

• Employed a concurrent-task paradigm comparing 14 early AD patients and 14 age/sex-matched normal controls (NC).
• Participants performed speeded unimanual tapping and speaking tasks (Speech Repetition - automatized, Speech Fluency - effortful) in single- and dual-task conditions.
• Utilized a proportional decrement score to quantify dual-task interference.

Main Results:

• Both groups experienced greater interference with effortful cognitive tasks.
• Early AD patients showed higher interference than NC during effortful speech tasks.
• Dual-task performance was comparable when combining tapping with the automatized Speech Repetition task.

Conclusions:

• A decline in general-purpose attentional resources is evident in early Alzheimer's disease.
• Dual-task performance is maintained in early AD when component tasks are sufficiently automatized.
• Findings highlight the importance of task automatization in compensating for attentional deficits in early AD.