A community health nurse is providing teaching to the family of a client who has primary dementia. Which of the following manifestations should the nurse tell the family to expect?

The correct answer is C: Forgetfulness gradually progressing to disorientation. In primary dementia, such as Alzheimer's disease, memory loss is a common early symptom that progresses to disorientation as the disease advances. This progression is due to the degeneration of brain cells affecting cognitive function. Choice A is incorrect because sensory acuity is typically not affected in primary dementia. Choice B is incorrect as emotional changes are varied and not universally decreased. Choice D is incorrect as personality changes are more likely to be subtle and related to cognitive decline rather than becoming the opposite of original traits.