Identify Conditions Underlying Dementia

Dementia has several possible individual causes, including Alzheimer’s disease, vascular conditions, Lewy body diseases, frontotemporal degeneration, and combinations of these and other conditions. Once a person has been diagnosed with dementia, the next step is to identify its cause or causes so that the most appropriate therapies and support services can be initiated.

Differential Diagnosis of Dementia from the Alzheimer’s Association provides useful information (e.g., a comparison table of various conditions that cause dementia), including usual course, presentation, risk factors, and imaging results.

Additionally, Understanding the Diagnosis from Georgia Memory Net provides educational resources about conditions that cause mild cognitive impairment and dementia.

“Once a person has been diagnosed with dementia,
the next step is to identify its cause or causes so that the most
appropriate therapies and support services can be initiated.”

Dementia Caused by Alzheimer’s Disease

Alzheimer’s disease is the most common cause of dementia. Current clinical criteria and procedures for the diagnosis of dementia caused by Alzheimer’s disease were developed by the National Institute on Aging and an Alzheimer’s Association workgroup (McKhann et al., 2011). In addition, the Alzheimer’s Association Professional Resources page provides information, tools, and resources, including those related to the diagnosis of Alzheimer’s disease.

Dementia Caused by Vascular Conditions

Various vascular conditions can cause dementia, including stroke, multiple small strokes, white matter brain lesions, atherosclerosis, and micro bleeds. A review by Korczyn and colleagues (2012) cites several sources of clinical criteria for diagnosis of dementia caused by vascular conditions, but notes that there is no gold standard for this diagnosis. The review by Korczyn and colleagues (2012) concludes that “the occurrence of comorbid changes in the brain, the availability of multiple diagnostic criteria, and reliance on several imaging methods and different criteria for abnormality make diagnosis imprecise.”

A Healthcare Provider’s Guide to Vascular Dementia from the University of California San Francisco Weill Institute for Neurosciences is an educational resource that discusses diagnostic and management considerations and the Alzheimer’s Association also provides information on the Differential Diagnosis of Vascular Dementia.

Dementia Caused by Lewy Body Disease

Lewy body dementias include two related disorders: dementia with Lewy bodies and Parkinson’s disease dementia. Criteria for the clinical diagnosis of probable and possible dementia with Lewy bodies were revised in 2017 (McKeith, 2017). These criteria include core clinical features, supportive clinical features, indicative biomarkers, and supportive biomarkers.

Other resources include the Lewy Body Composite Risk Score, which is a validated rating scale that may be used to assess Lewy body involvement and has been found to increase diagnostic probability (Galvin, 2015). This scale may be used after the completion of patient and caregiver interviews, a physical exam, and a neurological exam (Gavin, 2015). Additionally, the Lewy Body Dementia Association provides several useful publications, including a Comprehensive Symptoms Checklist. 

Dementia Caused by Frontotemporal Degeneration

Frontotemporal degeneration includes three dementia subtypes: behavioral variant frontotemporal dementia (bvFTD), semantic variant of primary progressive aphasia (svPPA), and nonfluent variant of primary progressive aphasia (nfvPPA). Neuropsychiatric symptoms are the most prominent symptoms of bvFTD, whereas difficulty with language and speech are the most prominent symptoms of svPPA and nfvPPA (Bott et al., 2014). Several published articles discuss diagnostic criteria for bvFTD (see Pijnenburg, 2011; Rascovsky et al., 2011) and primary progressive aphasia (Gorno-Tempini et al., 2011).

The Association for Frontotemporal Degeneration (AFTD) offers resources for health care professionals on diagnosing frontotemporal dementia, including a description of its key elements and references to diagnostic criteria. AFTD also provides resources for people newly diagnosed with frontotemporal degeneration and their families.

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