Movement Disorders

The answer first

Movement disorders divide into two families by the dominant motor sign: hypokinetic-rigid (too little movement — parkinsonism) and hyperkinetic (too much movement — tremor, chorea, dystonia, tics, myoclonus). The single most discriminating bedside observation is whether the problem is under-activity with slowness and stiffness, or excess, involuntary movement. ^[1]

For parkinsonism, the three questions that determine everything are: ^[1]

1. Is it idiopathic Parkinson's disease (PD), or one of the atypical, secondary, or mimicking disorders? The most common diagnostic error at the bedside is calling everything parkinsonian "Parkinson's disease." Roughly 1 in 4 patients labelled as PD in the community do not have it.
2. What is the dominant functional problem — motor (bradykinesia, gait, tremor, dyskinesia) or non-motor (cognition, mood, sleep, autonomic, hallucinations)? Management follows the dominant problem.
3. Are there red flags for an atypical or secondary cause? Early falls, rapid progression, symmetrical signs, absent rest tremor, early autonomic failure, early dementia, poor levodopa response — each of these is a flag to stop, reconsider, and not simply escalate levodopa. ^[1]

For PD, levodopa (combined with a peripheral dopa-decarboxylase inhibitor — carbidopa or benserazide) remains the single most effective symptomatic therapy and the gold standard. There is no role for "levodopa-sparing" fear — delaying levodopa does not prevent motor complications and denies patient best treatment available. ^[1]

DWE high-yield trap: When asked "best initial treatment for a 70-year-old with disabling motor features of Parkinson's disease," the answer is levodopa, not a dopamine agonist or MAO-B inhibitor. The PD MED trial ^[2] settled this — levodopa gave the best mobility and quality-of-life outcomes. Reserve agonists for younger patients with mild symptoms or to delay levodopa where dyskinesia risk is the dominant concern. ^[1]

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References14ShowHide

1. [1]Postuma RB, Berg D, Stern M, et al. MDS clinical diagnostic criteria for Parkinson's disease Mov Disord, 2015.PMID 26474316
2. [2]Gray R, Ives N, Rick C, et al. Long-term effectiveness of dopamine agonists and monoamine oxidase B inhibitors compared with levodopa as initial treatment for Parkinson's disease (PD MED): a large, open-label, pragmatic randomised trial Lancet, 2014.PMID 24928805
3. [3]Schuepbach WMM, Rau J, Knudsen K, et al. Neurostimulation for Parkinson's disease with early motor complications N Engl J Med, 2013.PMID 23406026
4. [4]Weintraub D, Koester J, Potenza MN, et al. Impulse control disorders in Parkinson disease: a cross-sectional study of 3090 patients Arch Neurol, 2010.PMID 20457959
5. [5]Cummings J, Isaacson S, Mills R, et al. Pimavanserin for patients with Parkinson's disease psychosis: a randomised, placebo-controlled phase 3 trial Lancet, 2014.PMID 24183563
6. [6]Höglinger GU, Respondek G, Stamelou M, et al. Clinical diagnosis of progressive supranuclear palsy: The movement disorder society criteria Mov Disord, 2017.PMID 28467028
7. [7]Wenning GK, Stankovic I, Vignatelli L, et al. The Movement Disorder Society Criteria for the Diagnosis of Multiple System Atrophy Mov Disord, 2022.PMID 35445419
8. [8]McKeith IG, Boeve BF, Dickson DW, et al. Diagnosis and management of dementia with Lewy bodies: Fourth consensus report of the DLB Consortium Neurology, 2017.PMID 28592453
9. [9]Huntington Study Group Tetrabenazine as antichorea therapy in Huntington disease: a randomized controlled trial Neurology, 2006.PMID 16476934
10. [10]Parkinson Study Group A controlled trial of rasagiline in early Parkinson disease: the TEMPO Study Arch Neurol, 2002.PMID 12470183
11. [11]Ferenci P, Caca K, Loudianos G, et al. Diagnosis and phenotypic classification of Wilson disease Liver Int, 2003.PMID 12955875
12. [12]Follett KA, Weaver FM, Stern M, et al. Pallidal versus subthalamic deep-brain stimulation for Parkinson's disease N Engl J Med, 2010.PMID 20519680
13. [13]Snow BJ, Macdonald L, McAuley D, et al. The effect of amantadine on levodopa-induced dyskinesias in Parkinson's disease: a double-blind, placebo-controlled study Clin Neuropharmacol, 2000.PMID 10803797
14. [14]Montplaisir J, Karrasch J, Haan J, et al. Ropinirole is effective in the long-term management of restless legs syndrome: a randomized controlled trial Mov Disord, 2006.PMID 16874755