Individuals with amnestic mild cognitive impairment (aMCI) show deficits on traditional episodic memory tasks and reductions in speed of performance on reaction time tasks. We present results on a novel task, the Cued-Recall Retrieval Speed Task (CRRST), designed to simultaneously measure level and speed of retrieval. A total of 390 older adults (mean age, 80.2 years), learned 16 words based on corresponding categorical cues. In the retrieval phase, we measured accuracy (% correct) and retrieval speed/reaction time (RT; time from cue presentation to voice onset of a correct response) across 6 trials. Compared to healthy elderly adults (HEA, n = 303), those with aMCI (n = 87) exhibited poorer performance in retrieval speed (difference = −0.13; p < .0001) and accuracy on the first trial (difference = −0.19; p < .0001), and their rate of improvement in retrieval speed was slower over subsequent trials. Those with aMCI also had greater within-person variability in processing speed (variance ratio = 1.22; p = .0098) and greater between-person variability in accuracy (variance ratio = 2.08; p = .0001) relative to HEA. Results are discussed in relation to the possibility that computer-based measures of cued-learning and processing speed variability may facilitate early detection of dementia in at-risk older adults. (JINS, 2012, 18, 260–268)

Speed of information processing in persons with postconcussion syndrome (PCS) was examined using word fluency tasks. Twenty patients with PCS and twenty controls matched for age, gender, and occupation were given two word fluency tasks, and the speed of word generation was measured. Response latencies were analyzed to determine whether slowed retrieval or degradation of words in semantic memory was responsible for problems with word retrieval after traumatic brain injury. The PCS group recalled fewer words, had significantly longer interresponse times, and took significantly longer to generate their first word than the controls. There was no evidence that either structure loss or slowness in word retrieval from semantic memory could account for the word fluency deficits. Rather, the findings suggest that the primary cause of word retrieval difficulties in patients with PCS is a generalized slowness of cognitive processing (JINS, 2007, 13, 178–182.)The study described was part of Maria Crawford's doctoral thesis. This research was supported by a University of Otago Research Grant awarded to Robert G. Knight and a Ph.D. scholarship awarded to Maria Crawford.