Impact on speech: About the Foreign Accent Syndrome

FAS is a rare sign of traumatic brain injury, apoplexy, or multiple sclerosis - but a recent casuistry hinted at an entirely different cause.

Initial manifestation of a transformation into a small cell neuroendocrine carcinoma (SNEC)

FAS is most commonly caused by brain damage resulting from stroke or traumatic brain injury. There are also other causes, including multiple sclerosis and a psychiatric variant associated with conversion disorder.2

A recent case vignette reports the occurrence of the disorder in a previously undescribed context.3,4 A Californian man in his 50s presented a strong Irish accent, even though he had no Irish background and had never been to Ireland. His accent was uncontrollable, present in all situations and became stronger over time. He had a history of metastatic hormone-sensitive prostate cancer (mHSPC) and was receiving androgen deprivation therapy and abiraterone acetate/prednisone. The only other symptom he complained of was weight loss.

Neurological examination and a head MRI were unremarkable and the man had no psychiatric history. However, despite an undetectable PSA level, a CT of the pelvis revealed a progression of his tumour. A biopsy revealed that transformation to SNEC had occurred.

Neurologists: usually a first point of contact for FAS

His appearance suggested an underlying paraneoplastic neurological disorder (PNS). PNS can affect all areas of the central and peripheral nervous system, as well as the neuromuscular end-plate and muscle, and often lead to severe disabilities. Causes include hormonal and immune-mediated reactions, especially autoimmune reactions triggered by the tumour and directed against common antigens of the tumour and the nervous system (so-called onconeural antigens).5

Such paraneoplastic phenomena are mostly first diagnosed by neurologists, as the neurological disorders precede the clinical manifestations of the tumour in most patients. Early detection and tumour therapy provides the best chance of stabilising paraneoplastic disorders.5

Despite chemotherapy, the patient's SNEC progressed, resulting in multifocal liver and bone, and later brain, metastases. He died under palliative care of probable progressive paraneoplastic paralysis. He retained his "Irish brogue" dialect until the end.

Implications for medical practice

The diagnosis of a paraneoplastic neurological disorder is most confidently made by detecting one of the well-characterised anti-onconeural antibodies in serum, but about one-third of affected individuals have no detectable antibodies (like the patient in our case) and 5-10% have atypical antibodies.5

MRI findings can only confirm a structural cause for the syndrome, such as a stroke or traumatic brain injury, but the diagnosis of FAS is ultimately made clinically. The change in accent associated with FAS is often due to altered movements of the patient's jaw and tongue. In the case of apoplexy, the disorder is not permanent and regresses as the person recovers.4

Further information Oncology and Urology

  1. Barreto, S. dos S. & Ortiz, K. Z. Speech in the foreign accent syndrome: differential diagnosis between organic and functional cases. Dement Neuropsychol 14, 329–332 (2020).
  2. Home - Foreign Accent Syndrome (FAS) | The University of Texas at Dallas.
  3. Broderick, A., Labriola, M. K., Shore, N. & Armstrong, A. J. Foreign accent syndrome as a heralding manifestation of transformation to small cell neuroendocrine prostate cancer. BMJ Case Reports CP 16, e251655 (2023).
  4. Kalyani, U. Never Been To Ireland, Man Develops Irish Accent Due To Prostate Cancer Complication. Medical Daily (2023).
  5. Orphanet: Paraneoplastic neurologic syndrome. Last visited: 09.02.2023