Women may have a better memory for words than men despite evidence of similar levels of shrinkage in areas of the brain that show the earliest signs of Alzheimer’s disease, according to a study published in the March 16, 2016, online issue of Neurology.
According to study author Erin E. Sundermann, PhD, of Albert Einstein College of Medicine in Bronx, NY, “One way to interpret the results is that because women have better verbal memory skills than men throughout life, women have a buffer of protection against loss of verbal memory before the effects of Alzheimer’s disease kick in. Because verbal memory tests are used to diagnose people with Alzheimer’s disease and its precursor, mild cognitive impairment, these tests may fail to detect mild cognitive impairment and Alzheimer’s disease in women until they are further along in the disease.”
The study included participants from the Alzheimer’s Disease Neuroimaging Initiative: 235 people with Alzheimer’s disease, 694 people with mild cognitive impairment that included memory problems, and 379 people with no memory or thinking problems. The groups’ performance on a test of verbal memory was compared to the size of the hippocampal area of the brain, which is responsible for verbal memory and affected in the early stages of Alzheimer’s disease.
Women performed better than men on the tests of both immediate recall and delayed recall among those showing evidence of minimal to moderate amounts of hippocampal shrinkage. At the high level of hippocampal shrinkage, there was no difference in the scores of men and women. At the score that indicates the start of verbal memory impairment, or 37 on a scale of zero to 75 for immediate recall, women showed greater evidence of hippocampal shrinkage (ratio of hippocampal volume to total brain volume multiplied by 103 was 5 compared to 6 for men).
Mary Sano, PhD, of Icahn School of Medicine at Mount Sinai in New York, NY, and a member of the American Academy of Neurology, said in a corresponding editorial, “At a public policy level, the potential health care cost for under-detection or delayed diagnosis of women with Alzheimer’s disease or its early stages is staggering and should motivate funding in this area.”
“If these results are confirmed, then we may need to adjust memory tests to account for the difference between men and women in order to improve our accuracy in diagnosis,” said Sundermann.
About this Alzheimer’s disease research
Funding: The Alzheimer’s Disease Neuroimaging Initiative was supported by the National Institute on Aging, National Institute of Biomedical Imaging and Bioengineering, Alzheimer’s Association, Alzheimer’s Drug Discovery Foundation, U.S. Food and Drug Administration, Abbott, Amorfix Life Sciences, AstraZeneca, Bayer HealthCare, BioClinica, Biogen Idec, Bristol-Myers Squibb, Eisai, Elan Pharmaceuticals, Eli Lilly, F. Hoffmann-La Roche and Genentech, GE Healthcare, Innogenetics, IXICO, Janssen Alzheimer Immunotherapy Research and Development, Johnson and Johnson Pharmaceutical Research and Development, Medpace, Merck, Meso Scale Diagnostics, Novartis Pharmaceuticals; Pfizer, Servier, Synarc and Takeda Pharmaceutical.
Source: Michelke Uher – AAN Image Source: The image is in the public domain. Original Research:Abstract for “Better verbal memory in women than men in MCI despite similar levels of hippocampal atrophy” by Erin E. Sundermann, Anat Biegon, Leah H. Rubin, Richard B. Lipton, Wenzhu Mowrey, Susan Landau, Pauline M. Maki, and For the Alzheimer’s Disease Neuroimaging Initiative in Neurology. Published online March 16 2016 doi:10.1212/WNL.0000000000002570
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 Alzheimer’s 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.
“Better verbal memory in women than men in MCI despite similar levels of hippocampal atrophy” by Erin E. Sundermann, Anat Biegon, Leah H. Rubin, Richard B. Lipton, Wenzhu Mowrey, Susan Landau, Pauline M. Maki, and For the Alzheimer’s Disease Neuroimaging Initiative in Neurology. Published online March 16 2016 doi:10.1212/WNL.0000000000002570