Search

Important insights into the early pathogenesis of Alzheimer's disease can be provided by studies of autosomal dominant Alzheimer's disease and Down syndrome. However, it is unclear whether the timing and spatial distribution of amyloid accumulation differs between people with autosomal dominant Alzheimer's disease and those with Down syndrome. We aimed to directly compare amyloid changes between these two groups of people.In this cross-sectional study, we included participants (aged ≥25 years) with Down syndrome and sibling controls who had MRI and amyloid PET scans in the first data release (January, 2020) of the Alzheimer's Biomarker Consortium-Down Syndrome (ABC-DS) study. We also included carriers of autosomal dominant Alzheimer's disease genetic mutations and non-carrier familial controls who were within a similar age range to ABC-DS participants (25-73 years) and had MRI and amyloid PET scans at the time of a data freeze (December, 2020) of the Dominantly Inherited Alzheimer Network (DIAN) study. Controls from the two studies were combined into a single group. All DIAN study participants had genetic testing to determine PSEN1, PSEN2, or APP mutation status. APOE genotype was determined from blood samples. CSF samples were collected in a subset of ABC-DS and DIAN participants and the ratio of amyloid β42 (Aβ42) to Aβ40 (Aβ42/40) was measured to evaluate its Spearman's correlation with amyloid PET. Global PET amyloid burden was compared with regards to cognitive status, APOE ɛ4 status, sex, age, and estimated years to symptom onset. We further analysed amyloid PET deposition by autosomal dominant mutation type. We also assessed regional patterns of amyloid accumulation by estimated number of years to symptom onset. Within a subset of participants the relationship between amyloid PET and CSF Aβ42/40 was evaluated.192 individuals with Down syndrome and 33 sibling controls from the ABC-DS study and 265 carriers of autosomal dominant Alzheimer's disease mutations and 169 non-carrier familial controls from the DIAN study were included in our analyses. PET amyloid centiloid and CSF Aβ42/40 were negatively correlated in carriers of autosomal dominant Alzheimer's disease mutations (n=216; r=-0·565; p0·0001) and in people with Down syndrome (n=32; r=-0·801; p0·0001). There was no difference in global PET amyloid burden between asymptomatic people with Down syndrome (mean 18·80 centiloids [SD 28·33]) versus asymptomatic mutation carriers (24·61 centiloids [30·27]; p=0·11) and between symptomatic people with Down syndrome (77·25 centiloids [41·76]) versus symptomatic mutation carriers (69·15 centiloids [51·10]; p=0·34). APOE ɛ4 status and sex had no effect on global amyloid PET deposition. Amyloid deposition was elevated significantly earlier in mutation carriers than in participants with Down syndrome (estimated years to symptom onset -23·0 vs -17·5; p=0·0002). PSEN1 mutations primarily drove this difference. Early amyloid accumulation occurred in striatal and cortical regions for both mutation carriers (n=265) and people with Down syndrome (n=128). Although mutation carriers had widespread amyloid accumulation in all cortical regions, the medial occipital regions were spared in people with Down syndrome.Despite minor differences, amyloid PET changes were similar between people with autosomal dominant Alzheimer's disease versus Down syndrome and strongly supported early amyloid dysregulation in individuals with Down syndrome. Individuals with Down syndrome aged at least 35 years might benefit from early intervention and warrant future inclusion in clinical trials, particularly given the relatively high incidence of Down syndrome.The National Institute on Aging, Riney and Brennan Funds, the Eunice Kennedy Shriver National Institute of Child Health and Human Development, the German Center for Neurodegenerative Diseases, and the Japan Agency for Medical Research and Development.

Background: Decision-making regarding gastrostomy tube (G-tube) placement prolongs hospital stay in the inpatient stroke setting. Studies have predicted who receives G-tube placement at discharge, but have not assessed which factors predict who is actually using a G-tube long-term by assessing dysphagia recovery and G-tube needs in follow-up. Methods: Stroke patients from an inpatient stroke service were prospectively recruited if dysphagia was identified on the clinical speech therapy dysphagia test, defined as Mann Assessment of Swallowing Ability (MASA) score < 178. Variables associated with dysphagia were prospectively collected. G-tubes were placed in patients according to standard clinical practice based on speech therapy recommendations and family discussion. Follow-up included a 6 week swallowing quality of life survey (SWAL-QOL, 12 items including if a G-tube is currently being used). Univariate predictors of G-tube use at 6 weeks were assessed allowing calculation of a “G-tube Score” for prediction of who required a G-tube at 6 weeks. Score performance was measured by receiver operating characteristic (ROC) curves and area under the curve (AUC). Results: Of 146 dysphagic patients (median NIHSS=15), 31% were discharged with a G-tube. Of those completing 6 week SWAL-QOL (N=61), 26% of patients who had received a G-tube, no longer needed a G-tube. Univariate predictors of needing a G-tube included: age ≥ 70 (p=0.017), NIHSS ≥ 18 (p=0.006), ICU admission (p=0.007), respiratory failure requiring intubation (p=0.001), and MASA score < 110 (p Conclusion: Carrying 2 of the following early factors: age ≥ 70, NIHSS ≥ 18, ICU admission, and intubation, yields a high likelihood of requiring a G-tube beyond 6 weeks post-stroke.