Required qualifications

CCET Level 7 and QTS/QTLS or equivalent
or QTS/QTLS or equivalent and PGCert /PGDip/MA/MEd/MSc in SEN (including psychological assessment) SpLD APC or equivalent
or QTS/QTLS or equivalent and Assessment Qualification at Level 7 e.g. CPT3A
or QTS/QTLS or equivalent and Professional Body Membership e.g. DA Guild MDG
A measure of concentration and decision making
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£161.99 £134.99

The Symbol Digit Modalities Test (SDM) is a measure of concentration and decision making.


  • It detects cognitive impairment in less than 5 minutes. This simple, economical test is a way for busy clinicians to screen for organic cerebral dysfunction in both children (8 years and older) and adults
  • Brief, easy to administer, and much less expensive than neuropsychological test batteries, the SDMT has demonstrated sensitivity in detecting not only the presence of brain damage, but also changes in cognitive functioning over time and in response to treatment.
  • It is highly effective as an initial screener, because it requires only 5 minutes yet detects cerebral dysfunction of almost any kind. However, like any single neuropsychological test, the SDMT is optimally used as part of a battery of instruments. 


The SDMT involves a simple substitution task that neurotypical children and adults can easily perform. Using a reference key, the examinee has 90 seconds to pair specific numbers with given geometric figures. Responses can be written or oral, and for either response mode, administration time is just 5 minutes. The WPS AutoScoreTM Test Form simplifies scoring.

Individuals with cerebral dysfunction perform poorly on the SDMT, in spite of normal or above average intelligence.

Examinees can give written or spoken responses and therefore the test can be used with almost anyone, including those with motor disabilities or speech disorders. As it involves only geometric figures and numbers, the SDMT is relatively culture free as well, and can be administered to people who do not speak English.

The written form of the test lends itself to group administration and is therefore an economical way to screen apparently neurotypical children and adults for possible motor, visual, learning, or other cerebral dysfunction.

Unlike other symbol substitution tests, the SDMT also gives you the opportunity to compare written and spoken responses from the same individual. The manual provides separate norms for written and oral administrations of the test. Norms for children are also separated by sex and age, whereas those for adults are separated by age group and level of education.

Complete kit includes:

  • Manual
  • 25 WPS Autoscore Test Forms.

Author: Aaron Smith PhD

Age range: 8 years to Adult

Format: Patient substitutes a number, either orally or written, for randomized presentations of geometric figures

Administration: Individual (written test can be performed with a group)

Testing time: 5 minutes

Publisher: WPS Publishing

Published date: 1973

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