Sunday, November 23, 2008

Cognition: Giving Wayfinding Directions

The British Psychological Society's (BPS) Research Digest blog has an interesting post about a study that concerns itself with giving route directions: link

Saturday, November 22, 2008

Neuropsychology Abstract of the Day: Neurodegeneration in Alzheimer Disease

de Jong LW, van der Hiele K, Veer IM, Houwing JJ, Westendorp RG, Bollen EL, de Bruin PW, Middelkoop HA, van Buchem MA, & van der Grond J. Strongly reduced volumes of putamen and thalamus in Alzheimer's disease: An MRI study. Brain. 2008 Nov 20.

Department of Radiology, Section Neuropsychology of the Department of Neurology, Department of Medical Statistics, Department of Geriatrics and Department of Neurology of the Leiden University Medical Center, Leiden, The Netherlands.

Atrophy is regarded a sensitive marker of neurodegenerative pathology. In addition to confirming the well-known presence of decreased global grey matter and hippocampal volumes in Alzheimer's disease, this study investigated whether deep grey matter structure also suffer degeneration in Alzheimer's disease, and whether such degeneration is associated with cognitive deterioration. In this cross-sectional correlation study, two groups were compared on volumes of seven subcortical regions: 70 memory complainers (MCs) and 69 subjects diagnosed with probable Alzheimer's disease. Using 3T 3D T1 MR images, volumes of nucleus accumbens, amygdala, caudate nucleus, hippocampus, pallidum, putamen and thalamus were automatically calculated by the FMRIB's Integrated Registration and Segmentation Tool (FIRST)-algorithm FMRIB's Software Library (FSL). Subsequently, the volumes of the different regions were correlated with cognitive test results. In addition to finding the expected association between hippocampal atrophy and cognitive decline in Alzheimer's disease, volumes of putamen and thalamus were significantly reduced in patients diagnosed with probable Alzheimer's disease. We also found that the decrease in volume correlated linearly with impaired global cognitive performance. These findings strongly suggest that, beside neo-cortical atrophy, deep grey matter structures in Alzheimer's disease suffer atrophy as well and that degenerative processes in the putamen and thalamus, like the hippocampus, may contribute to cognitive decline in Alzheimer's disease.

PMID: 19022861 [PubMed - as supplied by publisher]

Tuesday, November 18, 2008

The GEM Study

From an NIH press release earlier today:

Ginkgo Evaluation of Memory (GEM) Study Fails To Show Benefit in Preventing Dementia in the Elderly

The dietary supplement Ginkgo biloba was found to be ineffective in reducing the development of dementia and Alzheimer's disease in older people, according to a study published in the Journal of the American Medical Association1. Researchers led by Stephen T. DeKosky, M.D., formerly of the University of Pittsburgh, vice president and dean of the School of Medicine at the University of Virginia in Charlottesville, conducted the trial known as the Ginkgo Evaluation of Memory (GEM) study at four clinical sites over the course of 8 years. GEM is the largest clinical trial ever to evaluate ginkgo's effect on the occurrence of dementia.

This research was co-funded by five components of the National Institutes of Health (NIH): National Center for Complementary and Alternative Medicine (NCCAM); National Institute on Aging (NIA); National Heart, Lung, and Blood Institute; National Institute of Neurological Disorders and Stroke, and the Office of Dietary Supplements.

"We have made enormous progress in understanding the basic mechanisms involved in Alzheimer's disease, and we continue to pursue a vigorous program to translate what we know into the development and testing of new potential therapies for this devastating disease," said Richard Hodes, M.D., director of the NIA. "However, it is disappointing that the dietary supplement tested in this study had no effect in preventing Alzheimer's disease."

GEM enrolled 3,069 participants age 75 or older with normal cognition or mild cognitive impairment. Those with dementia were excluded from participation. After extensive medical and neuropsychological screening, participants were randomly assigned to receive twice-daily doses of either 120 milligrams of ginkgo extract or an identical-appearing placebo. The 240 milligrams daily dose of ginkgo was selected based on current dosage recommendations and prior clinical studies indicating possible effectiveness at this dose. The products used in the study were supplied by Schwabe Pharmaceuticals, a German company.

"According to the 2007 National Health Interview Survey, ginkgo is one of the top 10 natural products used by Americans," said Richard L. Nahin, Ph.D., M.P.H., acting director of the Division of Extramural Research at NCCAM. "It is important to conduct studies and build the scientific evidence base regarding botanical supplements through rigorous research, such as the GEM trial."

The study was conducted primarily to determine if ginkgo would decrease the incidence of all types of dementia and, more specifically, reduce the incidence of Alzheimer's disease. Secondarily, the study evaluated ginkgo for its effects on overall cognitive decline, functional disability, incidence of cardiovascular disease and stroke, and total mortality. The primary endpoint was the diagnosis of dementia as determined by an expert panel of clinicians using standard criteria for diagnosis. The patients with a diagnosis of dementia underwent magnetic resonance imaging scans to determine their dementia type.

"The results of this study confirm the importance of randomized trials in the development of new therapies for dementia and Alzheimer's disease and in determining therapeutic benefit not only for conventional therapies but also complementary therapies like ginkgo," said Dr. DeKosky, principal investigator on the GEM study. "If older patients are considering using ginkgo for preventing dementia, I urge them to speak with their health care providers about the results of this study and work together to create the best treatment plan."

Study participants were followed for an average of approximately 6 years (maximum of just over 7 years). During the study, 523 participants were diagnosed with dementia, 246 in the placebo group and 277 in the ginkgo group. Thus, ginkgo showed no overall effect for reducing all types of dementia or Alzheimer's disease. In addition, in analyzing safety data, the GEM study did not find significant adverse effects from ginkgo, in particular there was no evidence for increased bleeding risk in persons taking ginkgo.

Cognitive status was known for more than 93 percent of all participants at the end of the trial and 60 percent of active participants were taking their assigned study medication. There was no difference in adherence to taking medication between the ginkgo group and the placebo group.

"While this study revealed that ginkgo does not have an effect on reducing dementia in the study populationit does provide us with important information about how to design and conduct large dementia prevention trials in older adults" said Dr. Jeff Williamson, a geriatrician and principal investigator of the GEM Clinical Coordinating Center at Wake Forest University. "Future analyses will provide us with additional information on ginkgo's possible effects on cardiovascular disease, cancer, depression and other age-related conditions. We are especially grateful to the more than 3,000 older adults who dedicated many hours to helping us answer the important questions addressed by GEMS."

The GEM results will prove useful in determining how many participants are needed in future trials to provide clinically significant measures on outcomes such as occurrence of dementia. Future analysis of this study may also identify subgroups of these participants who may be at greater risk for developing dementia.

Data analysis for the trial was overseen by the University of Washington, Seattle and the four GEM institutions that participated in this study were

University of Pittsburgh
Wake Forest University, Winston-Salem, N.C.
Johns Hopkins University, Baltimore, Md.
University of California, Davis

[ ... Read the full press release ... ]

The GEM website: link

Monday, November 10, 2008

Neuropsychology Abstract of the Day: Aging and Cognition

Pratt LA, Weeks JD, & Goulding MR. Measures of cognitive functioning in the 1994-2000 Second Longitudinal Study of Aging. National Health Statistics Reports. 2008 Jul 7; (2): 1-15.

US Department of Health and Human Services, Centers for Disease Control and Prevention, National Center for Health Statistics, Hyattsville, MD 20782, USA.

OBJECTIVES: This report describes in detail the measures of cognitive functioning administered in the Second Longitudinal Study of Aging (LSOA II) and proposes a three-category cognitive impairment variable for analysts' use that is derived from the individual measures. METHODS: LSOA II self-respondents completed an 11-question cognitive functioning measure based on the Telephone Interview of Cognitive Status (TICS) instrument. Proxy respondents answered nine questions drawn from the short Informant Questionnaire on Cognitive Decline in the Elderly (IQCODE). Using cut points provided in the literature as a guide, a single three-level categorical measure of cognitive impairment was created: probable, possible, and no cognitive impairment. RESULTS: The cognitive functioning measures administered in LSOA II retain many of the favorable psychometric properties of the original TICS and IQCODE. The constructed cognitive impairment (CI) variable demonstrates good construct validity, and prevalence rates are generally consistent with those from other published studies. CONCLUSIONS: The categorical CI variable is easy to use and interpret and allows analysts the option of combining self- and proxy-respondent data in investigations of associations between CI and health outcomes, including continuing independence, progressive impairment, health care utilization patterns, and mortality.

PMID: 18839800 [PubMed - indexed for MEDLINE]

Sunday, November 02, 2008

Upcoming Event: 15-19 November 2008, Washington, D.C.

"Neuroscience 2008" --- The 38th annual meeting of the Society for Neuroscience, is scheduled for 15-19 November 2008 in Washington, D.C.

The location is the Walter E. Washington Convention Center.

Conference website.