We examined the performance of healthy young (n=57) and older adults (n=43) genotyped as apolipoprotein E-ε4 (APOE-ε4) carriers or APOE-ε4 non-carriers on a delayed match-to-sample task involving varying degrees of spatial interference hypothesized to assess spatial pattern separation. Older adult ε4 carriers were further divided into "impaired" and "unimpaired" groups based on their performance on a standardized test of verbal memory. We found that performance on the spatial pattern separation test increased as a function of decreased spatial interference across all groups. The older ε4 carriers in the impaired group performed significantly worse (p<.05) than unimpaired ε4 carriers, ε4 non-carriers, and young adults. The data suggest that spatial pattern separation may be less efficient in a subset of healthy older adults with subtle memory decline who are carriers of the ε4 allele. However, pattern separation performance may be comparable to that of young adults in a subset of older adult ε4 carriers and more broadly among non-carriers. Our findings offer additional evidence that pattern separation may vary in older adults, and they provide novel insight into pattern separation efficiency in ε4-positive older adults.

OBJECTIVES:The third edition of the California Verbal Learning Test (CVLT-3) includes a new index termed List A versus Novel/Unrelated recognition discriminability (RD) on the Yes/No Recognition trial. Whereas the Total RD index incorporates false positive (FP) errors associated with all distractors (including List B and semantically related items), the new List A versus Novel/Unrelated RD index incorporates only FP errors associated with novel, semantically unrelated distractors. Thus, in minimizing levels of source and semantic interference, the List A versus Novel/Unrelated RD index may yield purer assessments of yes/no recognition memory independent of vulnerability to source memory difficulties or semantic confusion, both of which are often seen in individuals with primarily frontal-system dysfunction (e.g., early Huntington's disease [HD]). METHODS:We compared the performance of individuals with Alzheimer's disease (AD) and HD in mild and moderate stages of dementia on CVLT-3 indices of Total RD and List A versus Novel/Unrelated RD. RESULTS:Although AD and HD subgroups exhibited deficits on both RD indices relative to healthy comparison groups, those with HD generally outperformed those with AD, and group differences were more robust on List A versus Novel/Unrelated RD than on Total RD. CONCLUSIONS:Our findings highlight the clinical utility of the new CVLT-3 List A versus Novel/Unrelated RD index, which (a) maximally assesses yes/no recognition memory independent of source and semantic interference; and (b) provides a greater differentiation between individuals whose memory disorder is primarily at the encoding/storage level (e.g., as in AD) versus at the retrieval level (e.g., as in early HD). (JINS, 2018, 24, 833-841).

Both the original and second editions of the California Verbal Learning Test (CVLT) provide an index of total recognition discriminability (TRD) but respectively utilize nonparametric and parametric formulas to compute the index. However, the degree to which population differences in TRD may vary across applications of these nonparametric and parametric formulas has not been explored. We evaluated individuals with Huntington's disease (HD), individuals with Alzheimer's disease (AD), healthy middle-aged adults, and healthy older adults who were administered the CVLT-II. Yes/no recognition memory indices were generated, including raw nonparametric TRD scores (as used in CVLT-I) and raw and standardized parametric TRD scores (as used in CVLT-II), as well as false positive (FP) rates. Overall, the patient groups had significantly lower TRD scores than their comparison groups. The application of nonparametric and parametric formulas resulted in comparable effect sizes for all group comparisons on raw TRD scores. Relative to the HD group, the AD group showed comparable standardized parametric TRD scores (despite lower raw nonparametric and parametric TRD scores), whereas the previous CVLT literature has shown that standardized TRD scores are lower in AD than in HD. Possible explanations for the similarity in standardized parametric TRD scores in the HD and AD groups in the present study are discussed, with an emphasis on the importance of evaluating TRD scores in the context of other indices such as FP rates in an effort to fully capture recognition memory function using the CVLT-II.

Objectives

Research has shown that analyzing intrusion errors generated on verbal learning and memory measures is helpful for distinguishing between the memory disorders associated with Alzheimer's disease (AD) and other neurological disorders, including Huntington's disease (HD). Moreover, preliminary evidence suggests that certain clinical populations may be prone to exhibit different types of intrusion errors.

Methods

We examined the prevalence of two new California Verbal Learning Test-3 (CVLT-3) intrusion subtypes - across-trial novel intrusions and across/within trial repeated intrusions - in individuals with AD or HD. We hypothesized that the encoding/storage impairment associated with medial-temporal involvement in AD would result in a greater number of novel intrusions on the delayed recall trials of the CVLT-3, whereas the executive dysfunction associated with subcortical-frontal involvement in HD would result in a greater number of repeated intrusions across trials.

Results

The AD group generated significantly more across-trial novel intrusions than across/within trial repeated intrusions on the delayed cued-recall trials, whereas the HD group showed the opposite pattern on the delayed free-recall trials.

Conclusions

These new intrusion subtypes, combined with traditional memory analyses (e.g., recall versus recognition performance), promise to enhance our ability to distinguish between the memory disorders associated with primarily medial-temporal versus subcortical-frontal involvement.

The present study examined age-related differences on the four false-positive (FP) error subtypes found on the California Verbal Learning Test-Second Edition yes/no recognition memory trial and the influence of these subtypes on source and novel recognition discriminability (SoRD and NRD, respectively) index calculations. Healthy older (n = 55) adults generally made more FP errors than healthy young adults (n = 57). Accordingly, older adults performed worse than young adults on all SoRD and NRD indices. However, the manner in which FP error subtypes were incorporated into SoRD and NRD index calculations impacted the magnitudes of observed differences between and within the two age groups on SoRD and NRD indices. The present findings underline the importance of examining FP errors in assessments of recognition memory abilities, and using more refined indices of recognition discriminability to further elucidate the nature of age-related recognition memory impairment.

Objective

Recall and recognition memory abilities are known to decline with increasing age, yet much of the evidence stems from studies that used simple measures of total target recall or recognition. The California Verbal Learning Test-Second Edition (CVLT-II) includes a new measure of recall discriminability that is analogous to recognition discriminability. These discriminability measures yield more thorough assessments of recall and recognition by accounting for intrusion and false positive errors, respectively. Research also has shown that women outperform men on verbal episodic memory tests. However, gender differences in recall and recognition discriminability and the age-by-gender interaction on these constructs have not been thoroughly examined.

Method

Cognitively healthy adults (N = 223) 18-91 years in age completed the CVLT-II. Multiple regression analyses were conducted to examine effects of age, gender, and the age-by-gender interaction on CVLT-II subtypes of recall and recognition discriminability.

Results

Discriminability scores decreased with increasing age, and women outperformed men. There was an age-by-gender interaction on total, immediate, and free recall discriminability - the negative association between age and scores was stronger in men than in women. Exploratory analyses revealed an inverted U-shaped relationship between age and recall discriminability scores in women.

Conclusions

The present findings support and expand upon the extant literature on aging, gender, and verbal episodic memory, plus describe a novel age-by-gender interaction intrinsic to subtypes of recall discriminability. The findings suggest that methods traditionally used to assess recognition memory function can be used to elucidate age- and gender-related changes in recall ability across the adult lifespan.