Younger-onset dementia

The term “presenile dementia”, used widely in the published literature until about 10 years ago, is no longer favoured and the terms “young-onset dementia”, “younger-onset dementia”,and “younger people with dementia” are now commonly used. Young-onset dementia (YOD) refers to the onset of dementia before the age of 65. Common symptoms include behavioral changes, psychiatric manifestations, and cognitive decline. Early-onset forms of adult neurodegenerative disease are the most common cause of YOD. Of these, the most common is AD followed by vascular dementia (VaD) and frontotemporal dementia (FTD). Other causes include alpha synuclein pathologies, Huntington's disease, Creutzfeldt Jakob disease, chronic traumatic encephalopathy, and Fahr's disease. Late-onset forms of childhood neurodegenerative conditions, such as mitochondrial disorders, lysosomal storage disorders, and leukodystrophies, are also important considerations and represent the most common causes of YOD in patients younger than 35 years. The reversible causes of YOD are inflammatory, infectious including, HIV dementia, neurosyphilis, Whipple disease, and progressive multifocal leukoencephalopathy (PML), toxic, and metabolic disorders. A systematic approach to diagnosing YOD allows for early diagnosis and intervention with the ultimate goal of symptom reversal or, at minimum, improvement in quality of life for patients and caregivers. MRI in investigation of young-onset dementia (A)Mild Alzheimer's disease: atrophy of hippocampi, (B C) Posterior cortical atrophy ) D) Pick's disease. (E) semantic dementia F) Creutzfeldt-Jakob disease (G), limbic encephalitis