Objective: To determine the diagnostic value of effort-associated behaviors ("huffing and puffing" spectrum) in patients with psychogenic movement disorders.
Methods: Three blinded clinicians rated presence, severity, and duration of effort-associated features during standing and walking tasks on edited videos of 131 patients with psychogenic gait disorders and 37 patients with organic gait disorders.
Results: Huffing, grunting, grimacing, and breath holding were the most common effort-associated behaviors in patients with psychogenic gait disorders, with a combined prevalence of 44% and disproportionate to the severity of gait impairment compared to organic gait disorders. The presence of "huffing and puffing"-type behaviors yielded a relatively low sensitivity but high specificity for the diagnosis of psychogenic movement disorders, increasing the odds of diagnosis 13-fold (95%, CI: 4.2-43.8) compared to organic gait disorders.
Conclusions: Demonstration of effort-associated behaviors during standing and walking strongly supports the psychogenic nature of disorders when gait is involved.
Keywords: excessive effort; psychogenic movement disorders.