Mixed Dementia Test & Diagnosis

Mixed dementia is a condition in which the signs and symptoms of more than one form of dementia occur simultaneously. The most common type of mixed dementia is characterized by both the protein deposits that are typically seen in those with Alzheimer’s disease, as well as blood vessel abnormalities that are generally linked with vascular dementia.

Given that mixed dementia exhibits symptoms of multiple types of dementia, it is not surprising that the clinical criteria for diagnosing mixed dementia is also complex. In fact, criteria for the disorder differ between even the International Classification of Diseases and Health Related Problems, 10^th revision (ICD-10) and the Alzheimer’s Disease Diagnostic Treatment Center (ADDTC).

In terms of the ICD-10, individuals are diagnosed with mixed dementia when they have met criteria for both vascular dementia and Alzheimer’s disease. The ADDTC defines mixed dementia as a disorder that presents with evidence of vascular disease in conjunction with symptoms of one or more other systemic or brain pathologies that are thought to be related to dementia.

A large portion of patients thought to suffer from mixed dementia are identified only after analysis of their autopsy. In fact, there is currently no validated biomarkers for identifying mixed dementia prior to the onset of symptoms. As such, when diagnosing mixed dementia, your physician will first gather an in depth account of your personal medical history, including any relevant familial history. This medical history interview will also include gathering information about the course of your specific symptoms of memory loss. Your doctor will also complete a comprehensive physical examination and a mental status exam. The mental status exam will include activities involving identifying what day and year it is, drawing a clock, repeating a series of words, and counting backwards.

There are some lab tests that may assist your doctor is diagnosing mixed dementia.

Some of the more common routine tests include:

• Thyroid tests – To check for hormone levels that may be indicative of an underactive thyroid
• Vitamin B12 blood test – To check for potential B12 vitamin deficiency
• Complete blood count – To check for potential infection
• AST or ALT blood test – To check liver function
• Chemistry screen – To check electrolyte levels and kidney function
• Glucose test – To check for abnormal blood sugar levels
• HIV testing – To check for AIDS
• Toxicology screen – To check for potential drugs
• Erythrocyte sedimentation rate – To check for any signs of inflammation within the body
• Lead test – To check for the presence of heavy metals in the body
• Antinuclear antibodies – To check for any autoimmune diseases
• Lumbar puncture test – To test protein levels in order to rule out any other potential diseases

If you have begun to notice any of these signs and symptoms of mixed dementia in yourself or someone you love, it is important to schedule an appointment with your doctor right away.

Sources

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4. Rockwood K, Macknight C, Wentzel C et al. The diagnosis of “mixed dementia” in the consortium for the investigation of vascular impairment of cognition (CIVIC). Ann N Y Acad Sci 2000;903:522–528.
5. Meyer J, McClintic K, Rogers R et al. Aetiological considerations and risk factors for multi-infarct dementia. J Neurol Neurosurg Psychiatry 1988;51:1489–1497.