Asymmetry of neurodegenerative disease-related pathologies: a cautionary note

Excerpt

Alzheimer’s disease (AD) is characterized neuropathologically by the presence of amyloid plaques (Aβ) and neurofibrillary tangles (tau). In addition, molecular pathologic examinations revealed concomitant protein depositions (in particular TDP-43 or α-synuclein), in various combinations with AD associated pathology [8]. Earlier papers evaluating senile changes in the brain noted variable asymmetric pathology without predominance of either hemisphere [6]. Two further papers, one on the evaluation of 5 patients [14] and another on 56 [7] indicated differences between the left and right hippocampus; differences were highly significant for plaques, tangles and also for granulovacuolar degeneration. Diagnostic and staging criteria developed after these studies did not provide recommendations for the side to be evaluated [2‐4, 10]. Furthermore, asymmetric distribution of neuronal loss and gliosis correlating with clinical symptoms (e.g., progressive aphasia or apraxia) is a feature of various molecular forms of frontotemporal lobar degeneration. Unilateral Creutzfeldt–Jakob disease has been also reported [15]. A recent comprehensive study indicated asymmetric involvement of the medial temporal lobe in patients with advanced argyrophilic grain disease [1]. …