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Published on: February 19, 2015
Test-retest reliability of two attention tests in schizophrenia
Posen Lee1, Ping-Chia Li, Chin-Hsuan Liu
1Department of Occupational Therapy, I-Shou University, Kaohsiung 824, Taiwan, Republic of China.
Summary
The Symbol Digit Modalities Test (SDMT) and Digit Vigilance Test (DVT) show good test-retest reliability for schizophrenia groups. However, practice effects and large variations limit their use for individual schizophrenia patients in short-term trials.
Area of Science:
- Neuropsychology
- Psychiatry
Background:
- Schizophrenia significantly impacts cognitive functions, particularly attention.
- The Symbol Digit Modalities Test (SDMT) and Digit Vigilance Test (DVT) are widely used to assess attention in schizophrenia.
- Understanding the test-retest reliability of these measures is crucial for clinical and research applications.
Purpose of the Study:
- To evaluate the test-retest reliability of the SDMT and DVT in individuals diagnosed with schizophrenia.
- To assess the stability of these attention tests over a 1-week interval.
Main Methods:
- 147 participants with schizophrenia completed the SDMT and DVT twice within a 1-week period.
- Test-retest reliability was quantified using intra-class correlation (ICC) coefficients.
- Bland-Altman analysis and paired t-tests were employed to assess agreement and systematic biases.
Main Results:
- High ICC values indicated good reliability for both tests (SDMT: 0.87, DVT: 0.83).
- Paired t-tests revealed significant practice effects for both measures.
- Bland-Altman analysis showed wide limits of agreement, suggesting substantial individual variability.
Conclusions:
- The SDMT and DVT demonstrate reliable performance at a group level in schizophrenia over a 1-week interval.
- Limitations include practice effects and significant individual variability, which may impact their utility in short-term clinical trials for individual assessment.
