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Hypertonia Assessment Tool (HAT)

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Supplemental: Cerebral Palsy (CP)
Short Description of Instrument
The Hypertonia Assessment Tool (HAT) was created as a standardized discriminative tool to differentiate between the 3 subtypes of hypertonia: spasticity, dystonia, and rigidity in the pediatric population (Knights et al., 2014). The Guyatt framework for measuring development was followed (Jethwa et al., 2010). The HAT can be used both in clinical and research settings. In clinical settings the HAT can be used to ensure children receive appropriate treatment; while in the research setting the HAT can be used to classify the hypertonia subtypes to report on specific outcomes.
Comments/Special Instructions
Good at identifying dystonia but better for spasticity. Better at identifying presence as opposed to absence of specific tonal abnormality.
Item Description (Type of tone)
  • Increased involuntary movements or postures of the designated limb with tactile stimulus of a distant body part (Dystonia)
  • Increased involuntary movements or postures with purposeful movement of a distant body part (Dystonia)
  • Velocity-dependent resistance to stretch (Spasticity)
  • Presence of spastic catch (Spasticity)
  • Equal resistance to passive stretch during bidirectional movement of a joint (Rigidity)
  • Increased tone with movement of a distant body part (Dystonia)  
  • Maintenance of limb position after passive movement (Rigidity)
The HAT includes 7 items in 3 subsets: 2 spasticity items, 2 rigidity items, and 3 dystonia items. Each item is scored in a yes/no format.
Scored as 0 as negative (no) , 1 if positive (yes)
The HAT is a short clinician-administered tool that can be used in both the clinical and research settings.
Albright L, Andrews M. Development of the Hypertonia Assessment Tool (HAT). Dev Med Child Neurol. 2010;52(5):411-412.
Jethwa A, Mink J, Macarthur C, Knights S, Fehlings T, Fehlings D. Development of the Hypertonia Assessment Tool (HAT): a discriminative tool for hypertonia in children. Dev Med Child Neurol. 2010;52(5):e83-e87.
Knights S, Datoo N, Kawamura A, Switzer L, Fehlings D. Further evaluation of the scoring, reliability, and validity of the Hypertonia Assessment Tool (HAT). J Child Neurol. 2014;29(4):500-504.


Document last updated November 2019