Primary progressive aphasia with parkinsonism

Dysphagia in primary progressive aphasia: Clinical predictors and neuroanatomical basis

BACKGROUND AND PURPOSE

Dysphagia is an important feature of neurodegenerative diseases and potentially life-threatening in primary progressive aphasia (PPA) but remains poorly characterized in these syndromes. We hypothesized that dysphagia would be more prevalent in nonfluent/agrammatic variant (nfv)PPA than other PPA syndromes, predicted by accompanying motor features, and associated with atrophy affecting regions implicated in swallowing control.

METHODS

In a retrospective case-control study at our tertiary referral centre, we recruited 56 patients with PPA (21 nfvPPA, 22 semantic variant [sv]PPA, 13 logopenic variant [lv]PPA). Using a pro forma based on caregiver surveys and clinical records, we documented dysphagia (present/absent) and associated, potentially predictive clinical, cognitive, and behavioural features. These were used to train a machine learning model. Patients' brain magnetic resonance imaging scans were assessed using voxel-based morphometry and region-of-interest analyses comparing differential atrophy profiles associated with dysphagia presence/absence.

RESULTS

Dysphagia was significantly more prevalent in nfvPPA (43% vs. 5% svPPA and no lvPPA). The machine learning model revealed a hierarchy of features predicting dysphagia in the nfvPPA group, with excellent classification accuracy (90.5%, 95% confidence interval = 77.9-100); the strongest predictor was orofacial apraxia, followed by older age, parkinsonism, more severe behavioural disturbance, and more severe cognitive impairment. Significant grey matter atrophy correlates of dysphagia in nfvPPA were identified in left middle frontal, right superior frontal, and right supramarginal gyri and right caudate.

CONCLUSIONS

Dysphagia is a common feature of nfvPPA, linked to underlying corticosubcortical network dysfunction. Clinicians should anticipate this symptom particularly in the context of other motor features and more severe disease.

Language impairment in primary progressive aphasia and other neurodegenerative diseases

Primary progressive aphasia (PPA) is a progressive neurodegenerative disease that disrupts the language capacity of an individual by selectively affecting the language network of brain. Although aphasic literature is replete with reports of brain damage responsible for various types of PPA, it does not provide a comprehensive understanding of whether PPA is an independent pathological condition or an atypical syndrome of neurodegenerative diseases (NDD). To address this ambiguity, we provide a detailed description of PPA, its variants and their brain anatomy. Subsequently, we unravel the relationship between PPA and NDDs like Alzheimer's, Parkinson's and Dyslexia. To substantiate the relationship further, we also provide a brief account of their genetic aetiology. In the final section, we offer an exhaustive approach towards the treatment of PPA by combining the existing language the rapies with clinical and pharmacological interventions.