Conditions that can lead to severe mental impairment include Alzheimer's disease and other forms of dementia, Parkinson’s disease, severe learning difficulties and strokes.
Mae cyflyrau sy'n gallu arwain at amhariad meddyliol difrifol yn cynnwys clefyd Alzheimer a mathau eraill o ddementia, clefyd Parkinson, anawsterau dysgu difrifol a strociau.