Erin E. Sundermann

Hormone therapy and cognitive function

BACKGROUND Clinical trials yield discrepant information about the impact of hormone therapy on verbal memory and executive function. This issue is clinically relevant because declines in verbal memory are the earliest predictor of Alzheimers disease and declines in executive function are central to some theories of normal, age-related changes in cognition. METHODS We conducted a systematic review of randomized clinical trials of hormone therapy (i.e. oral, transdermal, i.m.) and verbal memory, distinguishing studies in younger (i.e. <or=65 years of age; n = 9) versus older (i.e. >65 years; n = 7) women and studies involving estrogen alone versus estrogen plus progestogen. Out of 32 placebo-controlled trials, 17 were included (13 had no verbal memory measures and 2 involved cholinergic manipulations). We also provide a narrative review of 25 studies of executive function (two trials), since there are insufficient clinical trial data for systematic review. RESULTS There is some evidence for a beneficial effect of estrogen alone on verbal memory in younger naturally post-menopausal women and more consistent evidence from small-n studies of surgically post-menopausal women. There is stronger evidence of a detrimental effect of conjugated equine estrogen plus medroxyprogesterone acetate on verbal memory in younger and older post-menopausal women. Observational studies and pharmacological models of menopause provide initial evidence of improvements in executive function with hormone therapy. CONCLUSIONS Future studies should include measures of executive function and should address pressing clinical questions; including what formulation of combination hormone therapy is cognitively neutral/beneficial, yet effective in treating hot flashes in the early post-menopause.

A Review of Estrogen Receptor α Gene (ESR1) Polymorphisms, Mood, and Cognition

Objective:There are significant individual differences in the extent to which mood and cognition change as a function of reproductive stage, menstrual phase, postpartum, and hormone therapy use. This review explores the extent to which variations or polymorphisms in the estrogen receptor &agr; gene (ESR1) predict cognitive and mood outcomes. Methods:A literature search was conducted from 1995 to November 2009 through PubMed, Embase, and PsychINFO. Twenty-five manuscripts that summarize investigations of ESR1 in mental health were reviewed. Results:Among studies investigating ESR1 in relation to cognition, 11 of 14 case-control studies reported an association between ESR1 polymorphisms and risk for developing dementia. Three of four prospective cohort studies reported an association between ESR1 polymorphisms and significant cognitive decline. There are inconsistencies between case-control and cohort studies regarding whether specific ESR1 alleles increase or decrease the risk for cognitive dysfunction. The relationships between ESR1 and cognitive impairment tend to be specific to or driven by women and restricted to risk for Alzheimer disease rather than other dementia causes. Three of five studies examining ESR1 polymorphisms in relation to anxiety or depressive symptoms found significant associations. Significant associations have also been reported between ESR1 polymorphisms and childhood-onset mood disorder and premenstrual dysphoric disorder. Conclusions:A strong relationship between ESR1 variants and cognitive outcomes is evident, and preliminary evidence suggests a role of the ESR1 gene in certain mood outcomes. Insights into the discordant results will come from future studies that include haplotype analyses, analyses within specific ethnic/racial populations, and sex-stratified analyses.

Better verbal memory in women than men in MCI despite similar levels of hippocampal atrophy

Objective: To examine sex differences in the relationship between clinical symptoms related to Alzheimer disease (AD) (verbal memory deficits) and neurodegeneration (hippocampal volume/intracranial volume ratio [HpVR]) across AD stages. Methods: The sample included 379 healthy participants, 694 participants with amnestic mild cognitive impairment (aMCI), and 235 participants with AD and dementia from the Alzheimers Disease Neuroimaging Initiative who completed the Rey Auditory Verbal Learning Test (RAVLT). Cross-sectional analyses were conducted using linear regression to examine the interaction between sex and HpVR on RAVLT across and within diagnostic groups adjusting for age, education, and APOE ε4 status. Results: Across groups, there were significant sex × HpVR interactions for immediate and delayed recall (p < 0.01). Women outperformed men among individuals with moderate to larger HpVR, but not among individuals with smaller HpVR. In diagnosis-stratified analyses, the HpVR × sex interaction was significant in the aMCI group, but not in the control or AD dementia groups, for immediate and delayed recall (p < 0.01). Among controls, women outperformed men on both outcomes irrespective of HpVR (p < 0.001). In AD dementia, better RAVLT performance was independently associated with female sex (immediate, p = 0.04) and larger HpVR (delayed, p = 0.001). Conclusion: Women showed an advantage in verbal memory despite evidence of moderate hippocampal atrophy. This advantage may represent a sex-specific form of cognitive reserve delaying verbal memory decline until more advanced disease stages.

Crack cocaine use impairs anterior cingulate and prefrontal cortex function in women with HIV infection

Crack cocaine use is associated with impaired verbal memory in HIV-infected women more than uninfected women. To understand the neural basis for this impairment, this study examined the effects of crack cocaine use on activation of the prefrontal cortex (PFC) and strategic encoding during a verbal memory task in HIV-infected women. Three groups of HIV-infected women from the Chicago Consortium of the Women’s Interagency HIV Study were compared: current users of crack cocaine (n = 10), former users of cocaine (n = 11), and women who had never used cocaine (n = 9). Participants underwent functional magnetic resonance imaging during a verbal memory task and completed a neuropsychological test of verbal memory. On the neuropsychological test, current crack users performed significantly worse than other groups on semantic clustering, a measure of strategic encoding, p < 0.05. During encoding, activation in left anterior cingulate cortex (ACC) was lower in current and former cocaine users compared to never users. During recognition, activation in bilateral PFC, specifically left dorsal medial PFC and bilateral dorsolateral PFC, was lower in current and former users compared to women who had never used cocaine. Lower activation in left dorsolateral PFC was correlated with worse performance on the recognition task, p < 0.05. The verbal learning and memory deficits associated with cocaine use in women with HIV may be partially accounted for by alterations in ACC and PFC function.

Female advantage in verbal memory Evidence of sex-specific cognitive reserve

Objective: We investigated sex differences in verbal memory across different levels of neural dysfunction, measured by temporal lobe glucose metabolic rates (TLGluMR). Methods: Three hundred ninety controls and 672 participants with amnestic mild cognitive impairment (aMCI) and 254 with Alzheimer disease (AD) dementia from the Alzheimers Disease Neuroimaging Initiative completed the Rey Auditory Verbal Learning Test (RAVLT) and [18F]-fluorodeoxyglucose–PET. Cross-sectional analyses were conducted using linear regression to examine the sex by TLGluMR interaction on RAVLT performance in the overall sample and within diagnostic groups adjusting for age, education, and APOE ε4 genotype. Results: Across groups, female sex and higher TLGluMR and their interaction were associated with better verbal memory (p values ≤ 0.005). The female advantage in verbal memory varied by TLGluMR such that the advantage was greatest among individuals with moderate to high TLGluMR and minimal or absent among individuals with lower TLGluMR. Diagnosis-stratified analyses revealed that this interaction was driven by the aMCI group (p values = 0.009). The interaction was not significant in control and AD dementia groups. Conclusions: Women show better verbal memory than men in aMCI despite similar levels of brain hypometabolism. The lifelong advantage that females show over males in verbal memory might represent a form of cognitive reserve that delays verbal memory decline until more advanced pathology, as indexed by TLGluMR. This issue is clinically important because verbal memory scores are used in diagnosing aMCI and AD dementia.

Investigation of menopausal stage and symptoms on cognition in human immunodeficiency virus-infected women

ObjectiveWe evaluated the separate and interactive associations of menopausal stage, menopausal symptoms, and human immunodeficiency virus (HIV) infection with cognition. We hypothesized that HIV-infected perimenopausal women would show the greatest cognitive difficulties and that menopausal symptoms would be inversely associated with cognition. MethodsThis cross-sectional study included 708 HIV-infected and 278 HIV-uninfected premenopausal, perimenopausal, or postmenopausal women (64% African American; median age, 44 y) from the Women’s Interagency HIV Study. Participants completed tests of verbal learning and memory, attention/processing speed, and executive function. We administered a menopausal symptom questionnaire that assessed anxiety, vasomotor, and sleep symptoms and obtained measures of depressive symptoms. ResultsIn multivariable regression analyses controlling for relevant covariates, HIV infection, but not menopausal stage, was associated with worse performance on all cognitive measures (P’s < 0.05). Depressive symptoms were associated with lower cognitive performance on measures of verbal learning and memory, attention, and executive function (P’s < 0.05); anxiety symptoms were associated with lower performance on measures of verbal learning and memory (P’s < 0.05). Vasomotor symptoms were associated with worse attention (P < 0.05). HIV and anxiety symptoms interacted to influence verbal learning (P’s < 0.05); elevated anxiety was associated with worse verbal learning in HIV-infected women only. ConclusionsVasomotor, depressive, and anxiety symptoms, but not menopausal stage, are associated with worse cognitive performance in both HIV-infected and HIV-uninfected women, although elevated anxiety symptoms are more associated with verbal learning deficits in HIV-infected women. Because cognitive problems can interfere with everyday functioning, including treatment adherence, it may be important to screen and treat anxiety in HIV-infected women.

The effect of hormone therapy on olfactory sensitivity is dependent on apolipoprotein E genotype

Patients with Alzheimers disease (AD) show a deficit in olfactory threshold sensitivity. The Apolipoprotein E (ApoE) epsilon4 allele is associated with increased risk of AD and earlier symptom onset. Hormone therapy (HT) may exert neuroprotective effects on brain areas affected by AD. The current study investigated the effect of HT on performance on an olfactory threshold test in epsilon4 positive and epsilon4 negative non-hysterectomized, non-demented, elderly females and AD patients. Among the non-demented participants, epsilon4 positive females who had received HT performed 1) significantly better than those without HT, and 2) at levels similar to those of epsilon4 negative females. In contrast, those without HT who were epsilon4 positive performed significantly worse than those who were epsilon4 negative. HT had no effect on performance in AD patients regardless of epsilon4 status. These results suggest that HT may offer protection against loss of olfactory function in epsilon4 positive individuals in preclinical stages of AD. Future research is warranted in order to investigate further the neuroprotective role of HT on sensory and cognitive functions in non-demented aging individuals.

Estrogen and performance in recognition memory for olfactory and visual stimuli in females diagnosed with Alzheimer's disease

Patients with Alzheimers disease (AD) exhibit a deficit in episodic recognition memory for odors. It is hypothesized that the higher rate of AD in women may be due to estrogen-deprivation in postmenopausal women. Research suggests that estrogen may help to minimize cognitive decline in AD as well as postmenopausal olfactory loss. The current study examined the effects of estrogen replacement therapy (ERT) on performance of a recognition memory task for olfactory and visual stimuli in women AD patients. Participants included 24 women AD patients who were ERT users and 77 women AD patients who never used ERT. Compared with the ERT non-users, the ERT users committed significantly less false-positive memory errors for olfactory stimuli, whereas performance for visual stimuli did not differentiate between ERT users and non-users. The results suggest benefits of ERT could help ameliorate the earliest symptoms of AD, olfactory dysfunction, and memory impairment.

Prefrontal cortical volume loss is associated with stress-related deficits in verbal learning and memory in HIV-infected women☆

Deficits in verbal learning and memory are a prominent feature of neurocognitive function in HIV-infected women, and are associated with high levels of perceived stress. To understand the neurobiological factors contributing to this stress-related memory impairment, we examined the association between stress, verbal memory, and brain volumes in HIV-infected women. Participants included 38 HIV-infected women (Mean age=43.9years) from the Chicago Consortium of the Womens Interagency HIV Study (WIHS). Participants underwent structural magnetic resonance imaging (MRI) and completed standardized measures of verbal learning and memory and stress (Perceived Stress Scale-10; PSS-10). Brain volumes were evaluated in a priori regions of interest, including the medial temporal lobe (MTL) and prefrontal cortex (PFC). Compared to HIV-infected women with lower stress (PSS-10 scores in lower two tertiles), HIV-infected women with higher stress (scores in the top tertile), performed worse on measures of verbal learning and memory and showed smaller volumes bilaterally in the parahippocampal gyrus, superior frontal gyrus, middle frontal gyrus, and inferior frontal gyrus (ps<0.05). Reduced volumes in the inferior frontal gyrus, middle frontal gyrus, and superior frontal gyrus (all right hemisphere) were negatively associated with verbal learning and memory performance. Prefrontal cortical atrophy is associated with stress-related deficits in verbal learning and memory in HIV-infected women. The time course of these volume losses in relation to memory deficits has yet to be elucidated, but the magnitude of the volumetric differences between women with higher versus lower stress suggests a prolonged vulnerability due to chronic stress and/or early life trauma.

Genetic predictor of working memory and prefrontal function in women with HIV

The Val158Met (rs4680) single-nucleotide polymorphism (SNP) of the catechol-O-methyltransferase gene (COMT) influences executive function and prefrontal function through its effect on dopamine (DA) metabolism. Both HIV and the Val allele of the Val158Met SNP are associated with compromised executive function and inefficient prefrontal function. The present study used behavioral and neuroimaging techniques to determine independent and interactive associations between HIV serostatus and COMT genotype on working memory and prefrontal function in women. For the behavioral study, 54 HIV-infected and 33 HIV-uninfected women completed the 0-, 1-, and 2-back conditions of the verbal N-back, a working memory test. For the imaging study, 36 women (23 HIV-infected, 13 HIV-uninfected) underwent functional magnetic resonance imaging (fMRI) assessments while completing the N-back task. HIV-infected women demonstrated significantly worse N-back performance compared with HIV-uninfected women (p < 0.05). A significant serostatus by genotype interaction (p < 0.01) revealed that, among Val/Val, but not Met allele carriers, HIV-infected women performed significantly worse than HIV-uninfected controls across N-back conditions (p < 0.01). Analogous to behavioral findings, a serostatus by genotype interaction revealed that HIV-infected Val/Val carriers showed significantly greater prefrontal activation compared with HIV-uninfected Val/Val carriers (p < 0.01). Conversely, HIV-uninfected Met allele carriers demonstrated significantly greater prefrontal activation compared with HIV-infected Met allele carriers. Findings suggest that the combination of HIV infection and the Val/Val COMT genotype leads to working memory deficits and altered prefrontal function in HIV-infected individuals.