Movement disorders in the elderly

Classification. The most common movement disorders in the elderly are the parkinsonian syndromes. The non-parkinsonian movement disorders affecting older people are myoclonus, tremor, dystonia, tardive dyskinesia, chorea, functional movement disorders, and restless legs syndrome with periodic limb movements during sleep and while awake.

Phenomenology (Table 54.1). Myoclonus — sudden brief muscle jerks (positive) or sudden cessation of muscle activity (negative), "lightning brief", irregular and non-stereotyped. Tremor — rhythmic oscillation around a body part. Dystonia — sustained or intermittent contractions causing abnormal movements or postures. Chorea — irregular movements flitting from one body part to another with a dance-like appearance. Tardive dyskinesia — stereotyped masticatory movements with lip and tongue protrusion. Restless legs syndrome — an urge to move relieved by walking or stretching.

Commonest conditions and age relationship. Essential tremor is the most common, affecting up to 5% of adults over 60 and up to 21.7% over 95. Parkinsonism prevalence also rises with age, and mild extrapyramidal signs, ageing-related tremor and paratonia (gegenhalten) may be found in healthy older people as part of neurological ageing.

Drug-induced movement disorders are a major geriatric issue because of polypharmacy (Table 54.3): myoclonus — gabapentin, pregabalin, phenytoin, valproate, penicillins, cephalosporins, quinolones, SSRIs, lithium, opioids, amiodarone; tremor — SSRIs, tricyclics, lithium, beta-agonists, valproate, amiodarone, ciclosporin, tacrolimus, metoclopramide; dystonia and tardive dyskinesia — haloperidol, olanzapine, metoclopramide, prochlorperazine, phenytoin, carbamazepine; chorea — levodopa, dopamine agonists, neuroleptics, phenytoin, lamotrigine, lithium, oestrogens; restless legs — olanzapine, quetiapine, mirtazapine, topiramate. The medication list must be scrutinised in every case and offending drugs stopped where possible.

Diagnosis. Most are clinical diagnoses based on history and examination. Investigations are selective: metabolic and liver profile and thyroid studies; brain and spine imaging, particularly where symptoms are focal or cerebellar signs are present; CSF studies in inflammatory conditions; EEG and EMG to classify myoclonus; EMG for orthostatic tremor; and DaTSCAN to separate parkinsonism from essential tremor.

Treatment (Table 54.4). Reverse the cause first — stop the offending drug, correct metabolic derangement. Myoclonus — valproate, piracetam or levetiracetam for cortical myoclonus; botulinum toxin or GABAergic drugs for segmental and peripheral myoclonus. Tremor — propranolol and primidone, then topiramate, gabapentin or benzodiazepines, with DBS, gamma knife or focused ultrasound for refractory cases. Dystonia — physiotherapy, botulinum toxin injections, anticholinergic and GABAergic drugs, tetrabenazine for tardive dystonia, DBS for refractory cases. Tardive dyskinesia — slow down-titration of the offending agent, switch to clozapine or quetiapine, and valbenazine or deutetrabenazine. Chorea — tetrabenazine, deutetrabenazine or valbenazine, or neuroleptics. Restless legs syndrome — iron replacement if indicated, then α2δ ligands (gabapentin, pregabalin) or dopaminergic drugs first line and opioids second line. Functional movement disorders — convey the diagnosis as a genuine neurological condition with potential for recovery, with physiotherapy for motor retraining, CBT and treatment of comorbid anxiety and depression.

Restless legs syndrome — a complete reversal of first-line therapy. The AASM clinical practice guideline (Winkelman et al., Journal of Clinical Sleep Medicine, January 2025) now gives a strong recommendation for α2δ ligands — gabapentin, gabapentin enacarbil and pregabalin — and for intravenous ferric carboxymaltose, while dopamine agonists have been moved to "conditional against" and are no longer recommended as initial therapy because of augmentation, which affects roughly 7–10% of patients per year. Cabergoline carries a strong recommendation against use at any dose. Iron should be assessed in every patient, with serum ferritin targets above 75–100 µg/L and transferrin saturation above 20%, regardless of haemoglobin. This is a complete inversion of the 2012 guideline and is directly relevant to older patients, in whom augmentation and impulse-control disorders are especially damaging.