IDD and Dementia. Section 4: Screening, Diagnosis, and Treatment


In the general population, evaluation for a cognitive impairment is often prompted by the individual or a reliable informant who reports concerns regarding cognitive changes to a physician or other health care provider. Assessing for a cognitive impairment in someone with an IDD can be a more complicated task. It is often difficult to obtain an accurate personal history and to document the individual's baseline level of functioning when there is not ongoing involvement from family, physicians, or care staff. In addition, there may be poor record-keeping from childhood. Individuals with IDD are often served by different care providers through their lifetime (Moran et al., 2013) and family members or others who have known the person for a long time may not be able to objectively report on the person's preexisting abilities (Ball et al., 2004; Kirk et al., 2006).

Without an accurate history, a baseline level of performance cannot be established, which is critical for assessing cognitive and behavioral change (Ball et al., 2004; Jokinen et al., 2013; Kirk et al., 2006; Krinsky-McHale & Silverman, 2013; McCarron et al., 2014; Nieuwenhuis-Mark, 2009). Studies suggest conducting a detailed assessment between 25 and 40 years of age to establish the individual's baseline level of performance for individuals with Down syndrome (Jokinen et al., 2013; Kirk et al., 2006; O'Caoimh et al., 2013) and at age 50 for those with other intellectual disabilities (Jokinen et al., 2013; Kirk et al., 2006). Experts recommend periodic reassessments, after baseline has been assessed, so that substantial changes can be identified (Aylward et al., 1997; Kirk et al., 2006; Krinsky-McHale & Silverman, 2013; O'Caoimh et al., 2013).

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