Symbol Digit Modalities Test (SDMT)

Smith A


Basic description

  • The first reported symbol digit substitution task was described in 1913.
  • Aaron Smith and colleagues began piloting and using the Symbol Digit Modalities Task (SDMT) in the early 1960s.
  • The SDMT was copyrighted by Western Psychological Services (in 1973, 1976, and 1982), and the most recent (15th) printing of the manual was in 2017.
  • The SDMT has been submitted to the FDA COA Qualification Program

Smith A

Instrument copyrighted by WPS
To screen cerebral dysfunction or learning disorders in children and adults
To assess spontaneous recovery of cerebral functions as well as improvement resulting from specific therapeutic regimes
Therapeutic area
  • Nervous System Diseases
  • Mental Disorders
  • Pathological Conditions, Signs and Symptoms
Therapeutic indication
  • Brain Diseases
  • Generic for Mental Disorders
  • Learning Disabilities
Type of Clinical Outcome Assessment (COA)
  • perfo PerfO
Original language(s)
  • English
2 translation(s)
Bibliographic reference(s) of the original questionnaire

Smith A. Symbol Digit Modalities Test (Manual). Western Psychological Services. 1973 (WPS Website)


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