Hippocampal Sclerosis in the Oldest Old: A Finnish Population-Based Study

• Published in: Journal of Alzheimer's disease Vol. 63; no. 1; pp. 263 - 272
• Main Authors: Kero, Mia, Raunio, Anna, Polvikoski, Tuomo, Tienari, Pentti J., Paetau, Anders, Myllykangas, Liisa
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.01.2018
• Subjects: Aged, 80 and over; Aging - pathology; Community Health Planning; DNA-Binding Proteins - metabolism; Female; Finland - epidemiology; Functional Laterality; Hippocampus - pathology; Humans; Male; Neurodegenerative Diseases - epidemiology; Neurodegenerative Diseases - pathology; Sclerosis - epidemiology; Sequestosome-1 Protein - metabolism; tau Proteins - metabolism; Finland; hippocampal sclerosis without any comorbid neurodegenerative pathology; hippocampal sclerosis; TDP-43; very old; laterality; population-based; Dementia
• DOI: 10.3233/JAD-171068
• ISSN: 1387-2877

Background: There are only few population-based studies that have systemically investigated the prevalence of hippocampal sclerosis (HS) in the very old. The frequency of unilateral versus bilateral HS has been rarely studied. Objective: We investigated the prevalence and laterality of HS and its association with other neurodegenerative and vascular pathologies in a population-based sample of very elderly. Furthermore, the concomitant presence of immunoreactivity for TDP-43, p62, and HPtau was studied. Methods: The population-based Vantaa 85+ study includes all inhabitants of the city of Vantaa, who were >85 years in 1991 (n = 601). Neuropathological assessment was possible in 302 subjects. Severity of neuronal loss of CA sectors and subiculum was determined bilaterally by HE- staining. Immunohistochemistry performed using antibodies for TDP-43, p62, and HPtau. Results: Neuronal loss and pathological changes in the hippocampus sector CA1 and subiculum were observed in 47 of the 302 individuals (16%), and 51% of these changes were bilateral. HS without comorbid neurodegenerative pathology was found in 1/47 subjects with HS (2%). Dementia (p < 0.001) and TDP-43 immunopositivity of the granular cell layer of the dentate fascia (p < 0.001) were strongly associated with HS. The CERAD score, immunopositivity for HPtau and p62 in the granular cell layer of the fascia dentate were also associated. Conclusion: HS is prevalent (16%) in the oldest old population, but HS without any comorbid neurodegenerative pathology is rare. The high frequency of unilateral HS (49%) implied that bilateral sampling of hippocampi should be routine practice in neuropathological examination.