Table 1.
Summary of ligand-based PET findings in DS and AD.
| Authors | Final # of participants | Ligand; reference region | Results | Scanning feasibility issues |
|---|---|---|---|---|
| Landt et al. (2011) | 5 with DS/AD, 4 with DS only, 14 healthy controls without DS | PiB; Cerebellum | Only people with DS older than 45 had significant binding in regions of interest, whether or not they had dementia. | 1/11 (9.1%) DS participants who agreed to undergo scanning dropped out due to anxiety provoked by elevation of scanning table. |
| Nelson et al. (2011) | 19 with DS, 10 with AD, 10 controls | [18F]FDDNP; Cerebellum | Higher binding in DS (in parietal, medial temporal, lateral temporal, and frontal lobes and posterior cingulate gyrus), comparable or higher than AD group in all regions. Binding had positive association with age and behavioural dysfunction in several regions. | None reported. |
| Handen et al. (2012) | 7 with DS and no dementia | PiB; Cerebellum | The two subjects with PiB binding showed early striatal accumulation. | 1/8 (12.5%) participants was unable to complete PET imaging (reason not provided). |
| Hartley et al. (2014) | 63 with DS and no dementia | PiB; Subcortical white matter and cerebellum | Positive correlation between binding and age. No relationship between binding and cognitive measures when controlling for age (except for negative correlation with Rivermead Picture Recognition score when binding considered as continuous variable). | None for PET. In 9/63 scans (14.3%), T1 MRI failed due to motion artefact; An additional 2/54 (3.7%) did not have T2 acquisition. |
| Jennings et al. (2015) | 39 with DS, 2 of which had dementia | Florbetaben; Cerebellum | Uptake was correlated with age and was seen in people without AD. | None reported. |
| Rafii et al. (2015) | 12 with DS and no dementia | Florbetapir, Cerebellum | Amyloid load was associated with hippocampal atrophy. There was an inverse relationship between regional binding and glucose metabolism. No relationship between amyloid load and cognitive measures. | None reported. |
| Sabbagh et al. (2015) | 5 with DS and AD, 12 with DS only, 9 normal controls | Florbetapir; Pons | DS/AD had the highest uptake, followed by DS only. Age-related increases in binding were greater in DS group. | 1/5 (20%) DS/AD+ subjects had severe impairment and was too agitated to obtain quality MRI/PET; 1/12 (8.3%) DS/AD- withdrew after PET and did not complete MRI (reason not provided). |
| Annus et al. (2016) | 49 with DS (10 of which had dementia and 6 had cognitive decline) | PiB; Cerebellum | Binding begins in striatum around age 40, and was associated with dementia and cognitive decline. | None reported (most fell asleep during scan). |
| Cole et al. (2017) | 46 with DS (9 of which had dementia and 6 with cognitive decline), 30 controls | PiB; Cerebellum | PiB was associated with brain aging. No relationship between PiB and cognitive score directly, but within the PiB positive group there was a relationship between brain age and cognitive score. | None reported. |
| Lao et al. (2016) | 68 with DS and no dementia | PiB, Cerebellum | Positive correlation between binding and age, particularly in the striatum. | 1/72 (1.4%) excluded for being unable to complete PET scan; 1/72 (1.4%) excluded for no TI MRI scan (reasons not provided). |
| Lao et al. (2017) | 52 with DS and no dementia | PiB; Cerebellum | Binding occurred first in the striatum, and rate of change in uptake was correlated to pre-existing amyloid. This happened before evidence of dementia or atrophy. | None reported. |
Abbreviations: AD, Alzheimer's disease; DS, Down syndrome; FDDNP, 2-(1-{6-[(2-[fluorine-18]fluoroethyl)(methyl)amino]-2-naphthyl}-ethylidene)malononitrile; PiB, Pittsburgh compound B.