Sensory Tricks in Dystonia: A Systematic Review and Nested Quantitative Synthesis

Area of Science:

• Neurology
• Movement Disorders
• Clinical Neuroscience

Background:

• Sensory tricks (alleviating maneuvers) are voluntary actions that temporarily reduce dystonic movements and postures.
• These maneuvers are a key clinical feature of dystonia, offering diagnostic and mechanistic insights.
• Previous research has extensively described these phenomena but lacked systematic synthesis.

Purpose of the Study:

• To systematically review and synthesize evidence on alleviating maneuvers in dystonia.
• Characterize their prevalence, phenomenology, clinical effects, predictors, and neurobiological mechanisms.
• Evaluate the feasibility of quantitative synthesis and their translational relevance.

Main Methods:

• A systematic review with a nested quantitative synthesis was performed using a preregistered protocol.
• Searches included PubMed, Scopus, and Cochrane Library from inception.
• Qualitative synthesis covered phenomenology, effects, predictors, mechanisms, and applications; quantitative synthesis was planned but limited by heterogeneity.

Main Results:

• 53 studies met inclusion criteria; 31 contributed to qualitative synthesis, 26 to quantitative analyses.
• Alleviating maneuvers were reported in 13%-90% of dystonia patients, with a large cohort showing 68.7% effectiveness.
• Acute motor improvements (30%-50%) were observed but were transient; responsiveness correlated with shorter disease duration and botulinum toxin response.

Conclusions:

• Alleviating maneuvers are a consistent and informative feature of dystonia.
• Their magnitude, duration, and predictors are inconsistently measured.
• Standardized methods are needed for quantitative synthesis and evaluating device-based analogues.