Revising a diagnosis of functional neurological disorder: A
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A 62 year old female presented to neuropsychiatry services with a 3-year history of gradually progressive dysphonia, difficulty with keeping her eyes open and falls. Her medical history consisted of chronic obstructive pulmonary disease, type 2 diabetes mellitus, ischaemic heart disease, hypertension, grade 3b chronic kidney disease (secondary to hypertensive disease) and anaemia.

She had described all-over-body pain and difficulty with handwriting. She started experiencing difficulty keeping her eyes open voluntarily and found wearing sunglasses helped with this. Laryngoscopy revealed slowed movements of the hypopharynx and larynx. Speech and language therapy (SALT) assessment reported normal orofacial muscle function with effortful and delayed vocal production.

Neuropsychiatric review (3 years after symptom onset) revealed that she had started falling and stopped cooking or going outdoors (though she denied affective symptoms). Montreal Cognitive Assessment revealed a score of 22/30. Neurological examination demonstrated aphonia, eyelid apraxia and blepharospasm, near-constant use of sunglasses indoors and frequent touching of the corner of her eyes (a sensory geste).

MRI showed normal midbrain and pontine volumes, with hypointense signal within the substantia nigra, red nuclei and globus pallidus on susceptibility-weighted imaging (SWI), suggestive of iron deposition. CT showed no evidence of intracerebral calcification. The diagnosis was then revised from FND to an atypical akinetic rigid syndrome. Gait speed and efficiency had improved at the point of discharge from the rehabilitation programme, which was felt to be a non-specific effect of physiotherapy.

Her care was then transferred to neurology. Clinical examination revealed aphonia and apraxia of eyelid opening, mild limitation of upgaze, hypometric vertical saccades and frontalis overactivity. Bilateral bradykinesia, right-sided rigidity and right foot dystonia also were noted. A clinical diagnosis of progressive supranuclear palsy was made, and she received ongoing botulinum toxin treatment and SALT input.

It was notable that SALT continued to identify features suggestive of an additional functional component to her phonation difficulties, where speech appeared to reliably worsen during times of testing and improved with distraction. Breath-holding during speech was particularly prominent, though she was noted to be able to demonstrate an ability for free breath-flow during non-speech tasks.