Prospective Memory, Working Memory, Retrospective Memory and Self-Rated Memory Performance in Persons with Intellectual Disability

Table 1.

With intellectual disabilityWithout intellectual disabilityTasknm (SD)Vs. min^*Vs. max^**rangenm (SD)Vs. min^*Vs. max^**rangetProspective MemoryRemind-Me (number of reminders)180.22 (0.55)1.72−52.4^†0 − 2144.64 (1.95)8.93^†−4.53^†1 − 78.25^†,‡Picture-Based PM343.31 (1.39)13.92^†−7.10^†0–5144.93 (0.15)120.68^†−1.754.5–56.70^†,‡Mean Recognition Picture-Based PM338.61(1.86)26.57^†1.15^†4–101410 (0.00)—^§—^§10 − 104.28^†,‡d' Picture-Based PM ^¶332.39 (1.25)10.98^†−8.92^†−0.36–4.34134.13 (0.31)47.78^†−2.38^†3.48–4.347.41^†,‡Posted Letter180.83 (0.38)9.22^†−1.840–1180.83 (0.38)9.22^†−1.840–10.00Working memory and retrospective memoryListening Span2017.35 (7.88)9.85^†−14.00^†4–351830.72 (3.68)35.47^†−13.03^†24–366.81^†,‡Semantic Decisions of Listening Span2039.50 (2.54)32.52^†−4.39^†35–421741.88 (0.33)259.26^†−1.4641–424.15^†,‡Digit Span2223.41 (17.79)6.17^†−25.73^†3–671774 (18.62)16.39^†−10.45^†50–1258.58^†,‡Picture Span2319.26 (14.80)6.24^†−20.01^†4–671864.56 (12.78)21.47^†−5.47^†28–8010.32^†Subject performed tasks2110.71 (6.02)8.16^†−28.39^†0–291823.67 (5.09)19.74^†−20.29^†18–377.19 ^†Ratings and time conceptionTime conception229.64 (2.67)16.96^† (6.40^†,††)−4.16^†4–12——Self–rated PM3017.43 (2.96)17.48^†−12.17^†9–221618.00 (1.67)23.91^†−14.10^†16–230.83^‡Self-rated retrospective memory3118.03 (2.93)19.09^†−11.35^†12–231619.19 (1.97)22.67^†−9.75^†16–231.42^‡Staff ratings1930.42 (5.36)19.06^†−15.12^†16–35——^*One-tailed t-test versus the theoretical minimum performance^**One-tailed t-test versus the theoretical maximum performance^†p  <  0.05^‡Equal variance not assumed (significant result on Levene's test for equality in variance)^§Not computed (0 variance)^¶0 in a cell adjusted to 0.5^††One-tailed t-test versus the theoretical mean performance

Table 2.

TasksTasks1 r_S (n)2 r_S (n)3 r_S (n)4 r_S (n)5 r_S (n)6 r_S (n)7 r_S (n)8 r_S (n)9 r_S (n)1. Remind-Me (number of reminders)1.00 (18)0.14(13)0.43 (14)0.10 (14)−0.16 (13)−0.38 (14)0.15 (13)−0.12 (14)2. Picture-Based PM ^**0.15 (18)1.00 (33)(13)0.35 (13)0.41 (13)0.01 (12)0.07 (13)−0.21 (12)−0.20 (13)3. Recognition of PM cues0.20 (18)0.37 ^† (33)1.00 (33)4. Post-a-Letter(10)0.13 (18)0.22 (18)1.00 (18)−0.19 (18)−0.06 (17)0.09 (18)0.31 (17)0.07 (18)5. Listening Span0.06 (12)0.54 ^† (20)0.14 (20)0.00 (14)1.00 (20)0.10 (18)0.44 (18)−0.13 (17)−0.24 (18)6. Digit Span0.07 (14)0.51 ^† (22)0.59 ^‡ (22)0.23 (15)0.57 ^† (17)1.00 (22)−0.07 (17)−0.45 (16)0.34 (17)7. Picture Span−0.14 (14)0.53 ^‡ (23)0.30 (23)0.00 (14)0.40 (17)0.69 ^‡ (20)1.00 (23)0.13 (17)0.11 (18)8. Semantic decisions of Listening Span−0.08 (12)0.32 (20)0.12 (20)0.46 (14)0.33 (20)0.57 ^† (17)0.34 (17)1.00 (20)0.00 (17)9. Subject performed tasks0.11 (13)0.34 (21)0.37 (21)0.16 (15)0.48 ^† (17)0.56 ^† (20)0.32 (19)0.06 (17)1.00 (21)^*Spearman's rho^**d'^†Correlation is significant at the 0.05 level (2-tailed).^‡Correlation is significant at the 0.01 level (2-tailed).