| Digit span | Ask the subject to listen carefully and repeat a series of random numbers. Begin with a string of 2 digits, then increase. Read each number in a normal tone of voice at a rate of 1 digit per second, taking care not to group digits in pairs or sequences that could aid repetition; eg, 3 - 52 - 8 - 18 - 4 - 9 - 36 - 3 - 8 - 5 - 15 - 7 - 2 - 9 - 4 - 68 - 1 - 9 - 2 - 7 - 5 - 6 | Inability to repeat a string of at least 5 digits indicates probable impairment. |
| Vigilance "A" test | Read a list of 60 letters, among which the letter "A" appears with greater than random frequency. The subject is required to indicate (eg, by tapping on the desk) whenever the target letter is spoken by the examiner. The letter list is read in a normal tone at a rate of 1 letter per second; eg, L T P E A O A I C T D A L A A N I A B F S A M R A E O Z D P A K A L U C J T A E O | Count errors of omission and commission. More than 2 errors is considered abnormal. |
