Читать книгу Pathy's Principles and Practice of Geriatric Medicine - Группа авторов - Страница 88

While a range of cognitive changes are considered normal in the ageing population, cognitive decline beyond normal ageing is common. Approximately 14% of Americans over the age of 70 were recently estimated to have dementia, and 22% of this cohort have some form of mild cognitive impairment (MCI; (Plassman, et al., 2007; Plassman, et al., 2008). Global prevalence for dementia was estimated to be 24 million people and is expected to nearly double every 20 years, to 42 million in 2020 and 81 million in 2040 (Ferri, et al., 2005). The increased prevalence of MCI and dementia will present a significant public health challenge over the next several decades, with considerable individual, family, and societal impact, including functional deficits in daily activities, neuropsychiatric symptoms, and economic burden (Hill, et al., 2013; Wimo, Winblad, & Jonsson, 2010).

Aetiologies for mild cognitive impairment and dementia are varied. From the perspective of prognosis, these conditions generally fall into one of three categories. First, neurodegenerative dementias are characterized by progressive deterioration of cognitive and functional abilities. This category involves conditions like Alzheimer's disease, frontotemporal dementia, and Lewy body disease. A second category involves more stable or slowly progressive conditions. This includes conditions such as stroke, cerebrovascular disease, Parkinson's disease, and multiple sclerosis. Finally, a third prognostic category involves so‐called ‘reversible dementia’. Here, cognitive impairment may be remediated with the treatment of an underlying medical condition. Examples of reversible causes of cognitive impairment in older adults include normal‐pressure hydrocephalus, hypothyroidism, vitamin deficiencies, obstructive sleep apnoea, medication side effects, and mood disorders.