Dementia in Down’s syndrome: an MRI comparison with Alzheimer’s disease in the general population

Abstract

BackgroundDown’s syndrome (DS) is the most common genetic cause of intellectual disability. People with DS are at an increased risk of Alzheimer’s disease (AD) compared to the general population. Neuroimaging studies of AD have focused on medial temporal structures; however, to our knowledge, no in vivo case–control study exists comparing the anatomy of dementia in DS to people with AD in the general population. We therefore compared the in vivo brain anatomy of people with DS and dementia (DS+) to those with AD in the general population.MethodUsing MRI in 192 adults, we compared the volume of whole brain matter, lateral ventricles, temporal lobes and hippocampus in DS subjects with and without dementia (DS+, DS-), to each other and to three non-DS groups. These included one group of individuals with AD and two groups of controls (each age-matched for their respective DS and general population AD cohorts).ResultsAD and DS+ subjects showed significant reductions in the volume of the whole brain, hippocampus and temporal lobes and a significant elevation in the volume of the lateral ventricle, compared to their non-demented counterparts. People with DS+ had a smaller reduction in temporal lobe volume compared to individuals with AD.ConclusionsDS+ and AD subjects have a significant reduction in volume of the same brain regions. We found preliminary evidence that DS individuals may be more sensitive to tissue loss than others and have less ‘cognitive reserve’.

Brain-predicted age in Down syndrome is associated with beta amyloid deposition and cognitive decline

“…The observed increased brain-PAD supports the idea that the long-term consequences of DS include premature “age-like” changes to the structure of the brain. Previously, studies have shown lower brain volumes or abnormal cortical thickness in DS (Koran et al., 2014, Mullins et al., 2013, Pinter et al., 2001, Romano et al., 2016, Teipel et al., 2004) as well as a correlation between age and brain volume in individuals with DS, not seen in controls (Beacher et al., 2010, Krasuski et al., 2002). While these results have been used to indirectly infer the presence of “accelerated” brain aging in DS, our machine learning method provides a more direct approach of quantifying age-related changes to brain structure, by way of reference to a large lifespan training sample.…”

Down syndrome and Alzheimer's disease: Common pathways, common goals

“…Other techniques may be of value, such as high resolution electroencephalography to determine epileptic activity, because there appears to be a subset of individuals with DS and/or AD that have seizures [66]. Additionally, structural and functional magnetic resonance imaging in DS population, as in the general population, may reflect early AD neuropathophysiology [67,68]. …”

Síndrome de Down y enfermedad de Alzheimer: factores de riesgo, evaluación e intervención

“…Además, pueden desarrollar EA más pronto que otras personas debido a su producción aumentada de ßA y a su menor reserva cognitiva, pudiendo ésta ser el resultado de la combinación de la discapacidad intelectual pre-existente y de factores genéticos tales como la concentración de ßA y myo-inositol (mI) en el cerebro (Mullins et al, 2013). En este sentido, el nivel de funcionamiento cognitivo parece estar asociado con factores ambientales tales como el nivel de educación, años en una institución y el tipo de empleo (Temple et al, 2001).…”