Enhanced Imaging and Language Assessments for Primary Progressive Aphasia

Area of Science:

• Neuroscience
• Neurology
• Speech-Language Pathology

Background:

• Primary progressive aphasia (PPA) is a neurodegenerative syndrome with distinct variants.
• Differentiating logopenic variant PPA (lvPPA) from nonfluent agrammatic PPA is clinically challenging.
• Accurate diagnosis is crucial for prognosis and treatment of PPA variants.

Purpose of the Study:

• To identify a novel behavioral assessment to accurately distinguish lvPPA from other PPA variants.
• To correlate this assessment with specific patterns of brain atrophy in the temporal-inferior parietal cortex.
• To develop a clinically useful tool for PPA diagnosis.

Main Methods:

• An observational cohort study involving 227 individuals with PPA.
• Administration of standard and enhanced sentence reading and repetition subtests.
• Calculation of reading:repetition accuracy ratios and correlation with brain imaging data (superior temporal-inferior parietal volume).

Main Results:

• The sentence reading:repetition ratio significantly differed across PPA variants (p < 0.00001).
• The ratio accurately distinguished lvPPA from other variants with 87.5% diagnostic accuracy (AUC=0.85).
• The ratio correlated significantly with left:right superior temporal-inferior parietal volume (r=0.69, p=0.0087).

Conclusions:

• A novel sentence reading:repetition ratio serves as an efficient and reliable clinical assessment for differentiating lvPPA.
• This behavioral measure correlates with atrophy in the superior temporal-inferior parietal cortex, supporting lvPPA's link to phonological short-term memory deficits.
• The findings provide Class III evidence for the utility of this ratio in diagnosing lvPPA.