Section 1

A 70-year-old Chinese woman developed slowed movements and difficulty walking over 6 years, with progressively worsening mobility. Her posture had become noticeably stooped in the past year and she had had tremors in both hands for at least a decade. Her family reported cognitive decline over 6 years, which was gradual and non-fluctuating, with problems in episodic memory, planning and multitasking. She also had dream enactment suggesting REM-sleep behaviour disorder, constipation, urinary incontinence and a few syncopal episodes within the last 2 years. She had no visual, tactile or auditory hallucinations.

She had chronic schizophrenia, diagnosed in her 50 s, and took olanzapine and escitalopram. This had presented with depression with delusions; her low mood eventually resolved, but she still needed medication for psychosis. Her family confirmed that her personality had changed over time, becoming more apathetic.

On examination, there were bilateral resting tremors a re-emergent tremor in her left hand, and a mild voice tremor. There was moderate rigidity and bradykinesia in all limbs with bilateral upper limb dysmetria, especially on the left. Her gait was ataxic, characterised by truncal instability, a tendency to veer to the right, and she could not walk tandem. Smooth pursuit and saccadic eye movements, deep tendon reflexes, motor and sensory examination were normal. Her montreal cognitive assessment (score of 7/30) indicated an amnestic multidomain deficit, particularly affecting visuospatial function, executive function and attention, and so confirming the diagnosis of severe dementia.

She did not undergo peripheral electrophysiology as there was no clinical evidence of neuropathy.

Section 2

This patient presents with the phenomenology of Parkinsonism. Resting tremor with re-emergence classically occurs in Parkinson’s disease and people with prodromal Parkinson’s disease often have a history of non-motor symptoms, including REM-sleep behaviour disorder and constipation. However, …