Digit Span (DGS) is a measure of verbal short term and working memory that can be used in two formats, Forward Digit Span and Reverse Digit Span. This is a verbal task, with stimuli presented auditorily, and responses spoken by the participant and scored automatically by the software. Participants are presented with a random series of digits, and are asked to repeat them in either the order presented (forward span) or in reverse order (backwards span). While superficially very similar tasks, forward and backwards span rely on somewhat separable cognitive capacities: the simpler forward span task requires verbal working memory and attention, while the backwards span task additionally tests cognitive control and executive function.
1-3 minutes depending on achievement
The participant will hear a sequence of digits and then immediately be prompted to verbally repeat the sequence, either as it was heard (forwards), or in reverse order (backwards). If the participant responds correctly, the next trial presents a longer sequence. The task terminates when participants responded incorrectly on three occasions at a span length. The participant's span is the longest number of sequential digits that can accurately be remembered. Scores are total span reached for forward and reverse digits and number of errors.
Outcome measures include the direction of the task (forwards or backwards), the longest sequence successfully reached and passed, and the total number of attempts.