Correlates of recognition memory performance in amnestic mild cognitive impairment

Recognition Subtests for Form B of the Repeatable Battery for the Assessment of Neuropsychological Status: Preliminary Validation

OBJECTIVE

Develop and preliminarily validate recognition subtests for Form B of the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS).

METHOD

49 older adults with no cognitive impairment were compared to 53 individuals with a primary neurocognitive disorder (e.g., dementia, mild cognitive impairment, and traumatic brain injury) and 22 individuals with a primary psychiatric disorder (e.g., depression and anxiety) on three recognition subtests (list, story, and figure) for Form B of the RBANS in this observational study.

RESULTS

The individuals with a primary neurocognitive disorder performed significantly poorer on most of the recognition scores compared to those with no cognitive impairment and those with a primary psychiatric disorder, with these latter two groups being largely comparable. In the entire sample, for the recognition subtests, education only correlated with figure recognition scores, and neither age nor gender influenced recognition scores. The RBANS indexes correlated with most of the recognition scores in the expected directions.

CONCLUSIONS

The group differences in performance on these recognition subtests preliminarily validate these scores on Form B, which were not previously available. Furthermore, these scores tended to not be influenced by age, education, or gender, although they were related to overall cognitive functioning. Additional validation is needed in larger, better clinically-defined, and more diverse samples. Nonetheless, these findings support the inclusion of the newly-developed Form B recognition subtests in future clinical practice and research settings to enhance the accuracy of diagnoses and treatment recommendations.

Recognition Memory Performance as a Cognitive Marker of Prodromal Alzheimer's Disease

BACKGROUND

The utility of recognition memory for identifying persons with biomarker evidence of Alzheimer's disease (AD) is unclear since prior studies of mild cognitive impairment (MCI) relied only on clinical diagnosis and did not include simultaneous measures of central amyloidosis and tauopathy.

OBJECTIVE

We evaluated whether recognition memory and associated indices, including discriminability and response bias from signal detection theory, differentiate persons with amnestic MCI (aMCI) due to prodromal AD from non-prodromal AD.

METHOD

Sixty older adults with aMCI were classified as prodromal AD (n = 28) or non-prodromal AD (n = 32) based upon cerebrospinal fluid levels of amyloid-β and tau. Memory was assessed using the Hopkins Verbal Learning Test-Revised which includes free recall and recognition.

RESULTS

ANCOVAs adjusting for age indicated comparable (all p > 0.05) performances between prodromal and non-prodromal MCI groups respectively on traditional HVLT-R recognition measures of hits (mean±SD: 9.5±3.0 versus 10.9±1.7), false alarms (1.8±1.8 versus 1.5±1.5), and hits minus false alarms (7.7±3.0 versus 9.2±2.6). In contrast, discriminability (d'), which reflects how easily targets and distractors are distinguished, was significantly (p = 0.009) poorer in the prodromal versus non-prodromal groups (3.1±1.9 versus 4.8±2.0, effect size = 0.87). In addition, only d' significantly predicted group membership (OR = 0.66, CI = 0.48-0.92, p = 0.04). Response bias, the tendency to report that a target did or did not appear, was comparable between groups (0.08±1.1 versus -0.04±1.3).

CONCLUSION

Recognition discriminability is significantly poorer in aMCI with biomarker evidence of prodromal AD. In contrast to traditional recognition indices, discriminability from signal detection theory may be superior in identifying aMCI due to AD versus non-AD etiologies.

Sex differences in cortisol and memory following acute social stress in amnestic mild cognitive impairment

OBJECTIVE

Older adults with amnestic mild cognitive impairment (aMCI) develop Alzheimer's type dementia approximately 10 times faster annually than the normal population. Adrenal hormones are associated with aging and cognition. We investigated the relationship between acute stress, cortisol, and memory function in aMCI with an exploratory analysis of sex.

METHOD

Salivary cortisol was sampled diurnally and during two test sessions, one session with the Trier Social Stress Test (TSST), to explore differences in the relationship between cortisol and memory function in age-normal cognition (NA) and aMCI. Participants with aMCI (n = 6 women, 9 men; mean age = 75) or similarly aged NA (n = 9 women, 7 men, mean age = 75) were given tests of episodic, associative, and spatial working memory with a psychosocial stressor (TSST) in the second session.

RESULTS

The aMCI group performed worse on the memory tests than NA as expected, and males with aMCI had elevated cortisol levels on test days. Immediate episodic memory was enhanced by social stress in NA but not in the aMCI group, indicating that stress-induced alterations in memory are different in individuals with aMCI. High cortisol was associated with impaired performance on episodic memory in aMCI males only. Cortisol in Session 1 moderated the relationship with spatial working memory, whereby higher cortisol was associated with worse performance in NA, but better spatial working memory in aMCI. In addition, effects of aMCI on perceived anxiety in response to stress exposure were moderated by stress-induced cortisol in a sex-specific manner.

CONCLUSIONS

We show effects of aMCI on Test Session cortisol levels and effects on perceived anxiety, and stress-induced impairments in memory in males with aMCI in our exploratory sample. Future studies should explore sex as a biological variable as our findings suggest that effects at the confluence of aMCI and stress can be obfuscated without sex as a consideration.