The influence of memory on the speech-to-song illusion.

In the speech-to-song illusion a spoken phrase is presented repeatedly and begins to sound as if it is being sung. Anecdotal reports suggest that subsequent presentations of a previously heard phrase enhance the illusion, even if several hours or days have elapsed between presentations. In Experiment 1, we examined in a controlled laboratory setting whether memory traces for a previously heard phrase would influence song-like ratings to a subsequent presentation of that phrase. The results showed that word lists that were played several times throughout the experimental session were rated as being more song-like at the end of the experiment than word lists that were played only once in the experimental session. In Experiment 2, we examined if the memory traces that influenced the speech-to-song illusion were abstract in nature or exemplar-based by playing some word lists several times during the experiment in the same voice and playing other word lists several times during the experiment but in different voices. The results showed that word lists played in the same voice were rated as more song-like at the end of the experiment than word lists played in different voices. Many previous studies have examined how various aspects of the stimulus itself influences the perception of the speech-to-song illusion. The results of the present experiments demonstrate that memory traces of the stimulus also influence the speech-to-song illusion.

Effect of aerobic exercise on amyloid accumulation in preclinical Alzheimer's: A 1-year randomized controlled trial.

BACKGROUND: Our goal was to investigate the role of physical exercise to protect brain health as we age, including the potential to mitigate Alzheimer's-related pathology. We assessed the effect of 52 weeks of a supervised aerobic exercise program on amyloid accumulation, cognitive performance, and brain volume in cognitively normal older adults with elevated and sub-threshold levels of cerebral amyloid as measured by amyloid PET imaging. METHODS AND FINDINGS: This 52-week randomized controlled trial compared the effects of 150 minutes per week of aerobic exercise vs. education control intervention. A total of 117 underactive older adults (mean age 72.9 [7.7]) without evidence of cognitive impairment, with elevated (n = 79) or subthreshold (n = 38) levels of cerebral amyloid were randomized, and 110 participants completed the study. Exercise was conducted with supervision and monitoring by trained exercise specialists. We conducted 18F-AV45 PET imaging of cerebral amyloid and anatomical MRI for whole brain and hippocampal volume at baseline and Week 52 follow-up to index brain health. Neuropsychological tests were conducted at baseline, Week 26, and Week 52 to assess executive function, verbal memory, and visuospatial cognitive domains. Cardiorespiratory fitness testing was performed at baseline and Week 52 to assess response to exercise. The aerobic exercise group significantly improved cardiorespiratory fitness (11% vs. 1% in the control group) but there were no differences in change measures of amyloid, brain volume, or cognitive performance compared to control. CONCLUSIONS: Aerobic exercise was not associated with reduced amyloid accumulation in cognitively normal older adults with cerebral amyloid. In spite of strong systemic cardiorespiratory effects of the intervention, the observed lack of cognitive or brain structure benefits suggests brain benefits of exercise reported in other studies are likely to be related to non-amyloid effects. TRIAL REGISTRATION: NCT02000583; ClinicalTrials.gov.

Characterization of the Meal-Stimulated Incretin Response and Relationship With Structural Brain Outcomes in Aging and Alzheimer's Disease.

BACKGROUND: Individuals with Alzheimer's Disease (AD) are often characterized by systemic markers of insulin resistance; however, the broader effects of AD on other relevant metabolic hormones, such as incretins that affect insulin secretion and food intake, remains less clear. METHODS: Here, we leveraged a physiologically relevant meal tolerance test to assess diagnostic differences in these metabolic responses in cognitively healthy older adults (CH; n = 32) and AD (n = 23) participants. All individuals also underwent a comprehensive clinical examination, cognitive evaluation, and structural magnetic resonance imaging. RESULTS: The meal-stimulated response of glucose, insulin, and peptide tyrosine tyrosine (PYY) was significantly greater in individuals with AD as compared to CH. Voxel-based morphometry revealed negative relationships between brain volume and the meal-stimulated response of insulin, C-Peptide, and glucose-dependent insulinotropic polypeptide (GIP) in primarily parietal brain regions. CONCLUSION: Our findings are consistent with prior work that shows differences in metabolic regulation in AD and relationships with cognition and brain structure.

Baseline Prevalence of Polypharmacy in Older Hypertensive Study Subjects with Elevated Dementia Risk: Findings from the Risk Reduction for Alzheimer's Disease Study (rrAD).

BACKGROUND: Little is known about the prevalence of polypharmacy, the taking of five or more medications a day, in older adults with specific dementia risk factors. OBJECTIVE: To examine the prevalence of polypharmacy in participants at baseline in a vascular risk reduction focused Alzheimer's disease (rrAD) trial targeting older patients with hypertension and elevated dementia risk. METHODS: We conducted a detailed review of medications in a cross-sectional study of community-dwelling older adults with hypertension and elevated dementia risk. Medications were identified in a structured interview process with an onsite pharmacist or qualified designee. Polypharmacy was defined as use of five or more medications on a regular basis. Descriptive analyses were conducted on the sample as well as direct comparisons of subgroups of individuals with hypertension, diabetes, and hyperlipidemia. RESULTS: The 514 rrAD participants, mean age 68.8 (standard deviation [sd] 6), reported taking different combinations of 472 unique medications at their baseline visit. The median number of medications taken by participants was eight [Range 0-21], with 79.2% exhibiting polypharmacy (n = 407). Sites differed in their prevalence of polypharmacy, χ2(3) = 56.0, p < 0.001. A nearly identical percentage of the 2,077 prescribed (51.8%) and over the counter (48.2%) medications were present in the overall medication profile. The presence of diabetes (87.5%), hyperlipidemia (88.2%), or both (97.7%) was associated with a higher prevalence of polypharmacy than participants who exhibited hypertension in the absence of either of these conditions (63.2%), χ2(3) = 35.8, p < 0.001. CONCLUSION: Participants in a dementia risk study had high levels of polypharmacy, with the co-existence of diabetes or hyperlipidemia associated with a greater prevalence of polypharmacy as compared to having hypertension alone.