The commonly accepted cutoff scores for reliable digit span (RDS), a way to measure attention and working memory and assess suboptimal effort, are not appropriate for adults with epilepsy, according to a study of 63 patients with epilepsy or suspected seizures.
- A cutoff of ≤6 or ≤7 for RDS, which is part of the Wechsler Adult Intelligence Scale, is typically used in adult clinical populations.
- Maiman et al applied these thresholds to adult patients with epilepsy or suspected seizures, most of whom passed trial 2 of the Test for Memory Malingering with a score of 45 or above.
- A cutoff of 6 or less on the RDS subtest yielded a specificity of 85% while 7 or less yielded 77%.
- A secondary analysis concluded that a cutoff of 4 or less may be more appropriate for adults with epilepsy who have a low average IQ or lower.
Maiman M, Del Bene VA, MacAllister WS, et al. Reliable digit span: does it adequately measure suboptimal effort in an adult epilepsy population [published online ahead of print April 5, 2018]? Arch Clin Neuropsychol. doi: 10.1093/arclin/acy027