Executive dysfunction contributes to verbal encoding and retrieval deficits in posterior cortical atrophy

Area of Science:

• Neuroscience
• Cognitive Neurology
• Neurodegenerative Diseases

Background:

• Posterior Cortical Atrophy (PCA) is a neurodegenerative syndrome characterized by visual and spatial deficits.
• Early PCA diagnosis shows relative preservation of executive functions, language, and episodic memory.
• The progression of cognitive deficits in PCA, especially in executive functions impacting memory, remains understudied.

Purpose of the Study:

• To investigate executive function performance in PCA patients.
• To explore the association between executive function deficits and verbal episodic memory (encoding, storage, delayed recall).
• To identify potential neuroanatomical correlates of these cognitive deficits.

Main Methods:

• Nineteen individuals with PCA underwent comprehensive neuropsychological and neuroimaging assessments.
• A novel Neuropsychological Assessment Rating (NAR) scale was developed to quantify impairment severity.
• Hypothesis-driven analyses examined relationships between executive functions and verbal episodic memory.

Main Results:

• PCA patients exhibited significant deficits in working memory and lexical-semantic retrieval.
• These executive deficits were linked to atrophy in the left inferior parietal lobule.
• Impairments in verbal encoding and delayed recall were associated with executive deficits, but not recognition.

Conclusions:

• Deficits in verbal executive functions directly impact verbal episodic memory in PCA.
• Findings support the role of the posterior parietal cortex in executive functions crucial for verbal episodic memory.
• This study highlights the progressive nature of cognitive decline in PCA beyond initial visual symptoms.