Journal of Alzheimer's Disease - Volume 46, issue 3

Authors: Shen, Liang | Ji, Hong-Fang

Article Type: Research Article

Abstract: The associations between homocysteine (Hcy), folic acid, and vitamin B12 and Alzheimer’s disease (AD) have gained much interest, while remaining controversial. We aim to perform meta-analyses to evaluate comprehensively: i) Hcy, folic acid, and vitamin B12 levels in AD patients in comparison with controls; and ii) the association between Hcy, folic acid, and vitamin B12 levels and risk of AD. A literature search was performed using Medline and Scopus databases. A total of 68 studies were identified and included in the meta-analyses. Stata 12.0 statistical software was used to perform the meta-analyses. First, AD patients may have higher level of …Hcy, and lower levels of folate and vitamin B12 in plasma than controls. Further age-subgroup analysis showed no age effect for Hcy levels in plasma between AD patients and matched controls, while the differences in folate and vitamin B12 levels further enlarged with increased age. Second, data suggests that high Hcy and low folate levels may correlate with increased risk of AD occurrence. The comprehensive meta-analyses not only confirmed higher Hcy, lower folic acid, and vitamin B12 levels in AD patients than controls, but also implicated that high Hcy and low folic acid levels may be risk factors of AD. Further studies are encouraged to elucidate mechanisms linking these conditions. Show more

Keywords: Alzheimer’s disease, folic acid, homocysteine, meta-analysis, vitamin B12

DOI: 10.3233/JAD-150140

Citation: Journal of Alzheimer's Disease, vol. 46, no. 3, pp. 777-790, 2015

Authors: Oleson, Stephanie | Murphy, Claire

Article Type: Research Article

Abstract: Alzheimer’s disease (AD) is a neurodegenerative disorder characterized by progressive memory impairment and the presence of amyloid plaques and neurofibrillary tangles. The associated neuropathology originates in brain areas responsible for olfaction, which makes olfactory tasks potentially useful for assessing AD. The strongest genetic risk factor for AD is the apolipoprotein E (ApoE) ɛ4 allele that has been associated with increased cognitive and olfactory deficits. While individuals carrying one ɛ4 allele of the ApoE gene are at increased risk for AD relative to non-carriers, those with two copies of the ɛ4 allele demonstrate an even higher risk for developing AD. Furthermore, …homozygous ApoE ɛ4/4 individuals diagnosed with AD are known to have heightened amyloid burden and a more rapid rate of cognitive decline relative to heterozygous ɛ3/4 ApoE carriers. All of these factors suggest there are differences in severity and progression of AD as a function of possessing one versus two ɛ4 alleles. The current study investigated olfactory functioning in homozygous ɛ4/4 older adults diagnosed with probable AD. Compared to demographically matched ɛ3/3 and ɛ3/4 individuals, ɛ4/4 individuals showed deficits in odor identification and remote odor memory as measured by odor familiarity ratings. The current findings suggest that these particular domains of olfactory functioning may be more impaired in AD ɛ4/4 homozygotes compared to ɛ3/4 heterozygotes and ɛ3/3 homozygotes. These deficits give insight into how the presence of two ɛ4 alleles may differentially affect the progression of AD and suggest the usefulness of odor tasks in detecting those at risk for AD. Show more

Keywords: Alzheimer’s disease, ApoE, apolipoprotein E, olfaction, smell impairment

DOI: 10.3233/JAD-150089

Citation: Journal of Alzheimer's Disease, vol. 46, no. 3, pp. 791-803, 2015

Authors: Ramakers, Inez H.G.B. | Honings, Steven T.H. | Ponds, Rudolf W. | Aalten, Pauline | Köhler, Sebastian | Verhey, Frans R.J. | Visser, Pieter Jelle

Article Type: Research Article

Abstract: Background: The relation between psychological distress, personality traits, and cognitive decline in cognitively impaired patients remains unclear. Objective: To investigate the effect of psychological distress and personality traits on cognitive functioning in subjects with mild cognitive impairment (MCI); and to investigate the predictive accuracy of these factors for the development of dementia. Methods: MCI patients (n  = 343, age: 60.9±9.9 years, 38% female, and MMSE score: 28.1±1.9) were included from the Maastricht memory clinic. All patients underwent a standardized neuropsychological assessment (including tests for measuring mental speed (Trail Making Test (TMT) part A …and Stroop Color Word Test (SCWT) part I), executive functioning (TMT part B and SCWT part III), memory (15-Word Learning Tests), and verbal fluency (1-minute animals)), CT or MRI, and blood assessment. The Dutch Personality Questionnaire (DPQ) and the 90-items Symptom Check List (SCL-90) were used to measure personality traits and psychological distress. Conversion to dementia was assessed two, five, and ten years after baseline. The mean follow-up period was 6.7±3.4 years. Results: The Psychoneuroticism score of the SCL-90 was associated with slower performances on SCWT part I and TMT part A. The subdomain Neuroticism of the DPQ was also associated with slower scores on the TMT part A. At follow-up, 85 (25.9%) subjects had developed dementia. The SCL-90 total score, and the subscales, Anxiety, Somatization, Insufficiency in thought and action, and Sleeping problems were associated with a decreased risk for developing (AD-type) dementia. Conclusion: Psychological distress negatively affected information processing speed, but was not associated with an increased risk of developing dementia in patients with MCI. Show more

Keywords: Alzheimer’s disease, cognition, dementia, mild cognitive impairment, neuropsychological performances, neuroticism, personality, psychological distress

DOI: 10.3233/JAD-142493

Citation: Journal of Alzheimer's Disease, vol. 46, no. 3, pp. 805-812, 2015

Article Type: Meeting Report

DOI: 10.3233/JAD-150316

Citation: Journal of Alzheimer's Disease, vol. 46, no. 3, pp. 813-816, 2015