Large-Scale Study in The Lancet Neurology Documents Demographic, Clinical, and Biomarker Features Associated with Posterior Cortical Atrophy

Findings from a large-scaled research study published in The Lancet Neurology, provide new insight into the demographic characteristics of posterior cortical atrophy (PCA), which is a rare syndrome associated with the underlying neuropathologic features of Alzheimer disease (AD). According to the study results, PCA generally had an early age of onset of approximately 60 years and presented in its pure form absent clinical features of other neurodegenerative diseases. Most participants met diagnostic criteria for dementia, and 60% of the study cohort was female, indicating that the disease is more common in women than men. The results also identified strong associations between PCA syndrome and AD neuropathology, suggesting that the syndrome may be predictive for underlying AD. Additionally, the study authors identified new biomarker characteristics of PCA as well as core clinical features.

In this international cohort study, participants identified cases of PCA recorded in PubMed databases and requested deidentified data for participants who had a clinical diagnosis of posterior cortical atrophy and availability of AD cerebrospinal fluid (CSF) or PET biomarkers or diagnosis made at autopsy. Researchers evaluated neuropathologic, neuroimaging, clinical, biofluid, and demographic data for each participant. Data were analyzed for 1092 participants from 55 centers.

The following results were reported:

• The mean age at symptom onset was 59.4 years (95% CI, 58.9 to 59.8).
• The cohort was 60% female (95% CI, 56 to 64).
• PCA pure (defined as core PCA syndrome only) was present in 80% of participants (95% CI, 72 to 89) with the remaining 20% characterized as PCA plus (core PCA syndrome + core features of another neurodenerative syndrome)
• 43% carried at least one copy of the APOE allele.

In those participants in whom biomarker findings were reported:

• Amyloid beta (Aβ) was present in the CSF of 81% of participants assessed (95% CI, 9097).
• AmyloidPET was positive in 94% of participants assessed (95% CI, 90-97).
• Phosphorylated tau was present in the CSF of 65% of participants assessed (95% CI, 5675).
• TauPET was positive in 97% of participants assessed (95% CI, 93 to 100)
• PCA on MRI scans was found in 85% and predominant posterior [¹⁸F]FDGPET hypometablism in 97% of participants.

Common core clinical features associated with PCA included the following:

• Constructional dyspraxia (61%)
• Space perception deficit (49%)
• Simultagnosia (48%)
• Acalculia (47%)