Foreign Accent Syndrome: Neurological and Speech Disorder Mechanisms

Foreign Accent Syndrome (FAS) is a rare condition in which individuals abruptly develop speech patterns perceived as non-native, despite retaining their native language and lexicon. The syndrome can arise from focal brain lesions—most commonly cerebrovascular events or traumatic injury—that disrupt neural circuits underlying motor planning, prosody and segmental articulation. Cortical and subcortical structures implicated include the insula, inferior frontal gyrus, basal ganglia and cerebellum, reflecting the distributed nature of speech production networks. In contrast, psychogenic variants emerge without detectable structural damage, suggesting functional alterations in brain systems linked to emotion and motor control. Developmental forms of FAS have also been described, where subtle white matter anomalies in speech and emotion regulation tracts may underlie atypical phonetic patterns from adolescence. Clinically, FAS manifests as changes in intonation, timing and phoneme realization that listeners interpret as a foreign accent. Multidisciplinary assessment—integrating neurolinguistic analysis, neuropsychological profiling and advanced neuroimaging—has been key to delineating mechanisms, informing both diagnostic criteria and tailored therapeutic interventions. Understanding FAS offers unique insights into the neural organisation of speech, the interplay between cognitive and emotional networks, and neural plasticity following injury.

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Foreign Accent Syndrome: Neurological and Speech Disorder Mechanisms publication trend

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Technical terms

Foreign Accent Syndrome (FAS): A rare speech disorder characterised by the sudden appearance of a perceived non-native accent without loss of language competence.

Neurogenic: Originating from identifiable structural damage to the nervous system, such as stroke or traumatic injury.

Psychogenic: Arising from psychological factors without detectable structural brain lesions.

Lesion network mapping: A method that links focal brain lesions to distributed functional networks using connectivity data to predict symptomatology.

Diffusion tensor imaging (DTI): An MRI technique that measures the diffusion of water molecules to assess the microstructural integrity of white matter pathways.

References

1. Multidisciplinary Assessment and Diagnosis of Conversion Disorder in a Patient with Foreign Accent Syndrome. Behavioural Neurology (2011).
2. Mild Developmental Foreign Accent Syndrome and Psychiatric Comorbidity: Altered White Matter Integrity in Speech and Emotion Regulation Networks. Frontiers in Human Neuroscience (2016).
3. Cognitive Behavioral Therapy for Foreign Accent Syndrome: A Single-Case Experimental Design. Clinical Case Studies (2020).
4. Patient with Foreign Accent Syndrome in Post Infarct Thrombotic Stroke: A Case Report. Magna Neurologica (2024).