Reversible Dropped Head Syndrome Due to Olanzapine-Associated Cervical Dystonia in C9orf72-Associated bvFTD Within the FTD–ALS Spectrum

Dropped head syndrome (DHS) is an uncommon but clinically significant postural abnormality that may arise from heterogeneous neuromuscular or central mechanisms.In patients with neurodegenerative disease, DHS is often attributed to weakness of the cervical extensor musculature, yet dystonic mechanisms may produce a similar phenotype and may be potentially reversible if correctly recognized. 1,26-year-old woman with genetically confirmed C9orf72-associated behavioral variant frontotemporal dementia within the FTD-ALS spectrum developed progressive DHS evolving into fixed antecollis during olanzapine treatment.Her baseline neurodegenerative disorder was