Symbol-Digit Modalities Test

Symbol-Digit Modalities Test

The Symbol-Digit Modalities Test (SDMT) is a five minute assessment that quickly screens the participant for any kind of cerebral dysfunction using a simple substitution task. It is excellent for use in drug and alcohol rehabilitation centers as it is easy to administer and remarkably accurate when it comes to detecting the presence of brain damage and other changes in a patient’s cognitive functioning. It is effective because those with cerebral dysfunction will always perform poorly due to deficiencies in attention span, scanning abilities and motor skills. This is regardless of the intelligence levels of an individual.

One study found that results from the SDMT were not correlated to the age, gender and income of the individual tested. This means that any results gained are representative of the patient’s mental abilities alone, rather than external lifestyle variables. The same study indicated that there may have been a correlation between education and how a participant performed in the test. More research will have to be performed in order to confirm this. Overall, these findings show that this test is a reliable indicator of whether a patient is suffering from a mental disorder, without having to take into account any external factors to explain the results.

Administrating the Symbol-Digit Modalities Test

When undertaking the SDMT, a participant is given a reference key that they must use to help them connect basic roman numerals to a series of geometric shapes. Responses can be verbal or written, and the entire test should be finished in 90 seconds. Scoring and evaluation of the test takes a further five minutes to complete. The test is also very versatile, making it ideal for clinical settings. Because responses can be written or spoken, it can be used with a broad spectrum of patients, including those suffering from motor disabilities and speech impediments. It is also culturally-unbiased since it involves figures and numerals and can be administered to non-English speakers as well.

The written form of the test is more effective for use in alcohol rehabilitation centers, specifically because it has been designed for the group environment. It is a quick, easy way to screen patients for any brain damage or cognitive deficiencies. Additionally, the written and spoken tests can be used together to compare results from the same individual, thus gaining further insight into how their brain functions. For more extensive results, it is important to use the SDMT with a number of other clinical assessments.

Studies on the SDMT and Alcoholism

As for how results from the Symbol-Digit Modalities Test are affected by drinking habits, a look at several papers on the subject reveals generally mixed findings.

One study found that patients with chronic alcoholism performed normally when it came to completing cognitive tasks. The researchers used the Letter Digit Substitution Test (LDST) which is a modified version of the SDMT. They suggested that if there were any discrepancies in how the patient performed in the test, this was then caused by a more serious mental disorder, such as Korsakoff’s Syndrome.

A second paper discovered that results from tests such as the SDMT were non-linearly related to the amount of alcohol regularly consumed. In this study, abstainers actually performed poorly when compared to light drinkers. In addition to this, when adjustments were made to account for education and ethnicity, heavy drinkers performed equally as well as those who drank alcohol socially.

Despite these findings, the SDMT is still useful within drug and alcohol rehabilitation centers. It can be used to assess whether a patient is suffering from a mental disorder, not only chronic alcoholism. Used in conjunction with other assessments, the Symbol-Digit Modalities Test can provide the administrator with a good idea of the general state of the participant’s mental functioning.