Speech and language disorders as core diagnostic tools for differentiation of neurodegenerative diseases

Abstract

AbstractBackgroundA patient suffering from a neurodegenerative disease may demonstrate various combinations of dysarthria, aphasia, and apraxia. Besides, a speech disorder can be a primary and dominant sign (primary progressive aphasia or apraxia), or can develop secondarily as part of general clinical picture. No unified approach to classification and diagnostics of various speech disorder forms has been developed to date. Aim: to study speech disorders in various forms of neurodegenerative diseases, to assess common structure, clinical‐neuroimaging heterogeneity, and to develop a unified algorithm for differential diagnosis.Method1008 patients with neurodegenerative diseases were included in the study by continuous sampling of consultant practice specializing in neurodegenerations: 234 AD, 118 DLB, 62 FTD (behavior and language variants), 366 PD, 22 PSP, 14 CBS, and 292 patients with unspecified and other forms of neurodegenerative pathology. All patients were screened for cortical speech disorders (pure dysarthria was not considered). Patients demonstrating speech and language disorders were tested using the speech disorder assessment test battery we have developed. Structural MRI was performed for all the patients with speech and language disorders to assess ROI.Resultspeech and language disorders were identified in 41% of patients in aggregate group, 78% of AD, 48% of DLB, 31% of PD, 82% of FTD, 64% of PSP, and 96% of CBS patients. Based on the detailed speech assessment battery in aggregate group of all the neurodegenerative diseases 7 subtypes of speech and language disorders were highlighted by means of cluster analysis (Figure 1), principal component method allowed to identify the most significant tests for differentiation of these forms. Aphasia forms and neurodegenerative diseases forms were matched using multinomial logistic regression (Figure 2). We identified the main ROI for all subtypes (Figure 3)Conclusionspeech disorders in patients with neurodegenerative diseases have a specific structure with clinical‐neuroimaging heterogeneity, which allowed to develop a unified algorithm for differential diagnosis.