Should Paratonia Be Considered a Movement Disorder? Implications for Clinical Management.

Paratonia is an involuntary and variable resistance to passive movement that emerges with cognitive decline in dementias of different etiologies, with prevalence approaching 90% to 100% in end-stage disease. It is common in Parkinson disease and the atypical parkinsonisms. The involuntary resistance is frequently interpreted as volitional refusal of care and may be managed with psychotropic medication. We propose that paratonia meets the criterion by which a movement disorder is defined, with a reproducible and distinct clinical phenomenology that is operationalized in a validated bedside instrument and is distinguishable from parkinsonian rigidity, spasticity, and dystonia. We present a preliminary staging schematic in which treatment with botulinum toxin A (BoNT-A) is indicated when the posturing interferes with care and the contraction remains dynamic, before fixed contracture. Preliminary evidence from a randomized pilot trial and observational studies supports BoNT-A for care-interfering paratonia. Classification of paratonia as a movement disorder would enable a dedicated research, education and advocacy platform to advance clinical care.