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Symbol Digit Modalities Test

Aaron Smith, PhD

Screens for organic cerebral dysfunction in both children and adults
Paper and pencil
Age range:
8 years to 78 years
5 minutes
Qualification level:
All qualifications for Level B plus an advanced professional degree that provides appropriate training in the administration and interpretation of psychological tests, or license or certification from an agency that requires appropriate training and experience in the ethical and competent use of psychological tests. Close

Brief and easy to administer, the SDMT has demonstrated remarkable sensitivity in detecting not only the presence of brain damage but also changes in cognitive functioning over time and in response to treatment.

An economical way to screen apparently normal children and adults for cerebral dysfunction

  • A simple substitution task, the SDMT gives the examinee 90 seconds to pair specific numbers with given geometric figures.
  • Examinees can give either written or spoken responses, making the test well suited for use with individuals who have motor disabilities or speech disorders.
  • Because it involves only geometric figures and numbers, the SDMT is relatively free of cultural bias and can be administered to individuals who do not speak English.

Effective in a wide range of clinical applications

The SDMT has been documented as effective in the differentiation of brain-damaged patients from psychotic patients, the differentiation of organic disorders from depressive disorders, the early detection of senile dementia and Huntington’s disease, the differential diagnosis of children with learning disorders, and the early identification of children likely to have reading problems.

Note: Stopwatch is required for administration.