patients with dementia

2nd week of my neuro placement. I had to treat a patient who came in with increasing confusion and slurred speech (with ? aphasia). There was nothing much written in his file regarding his social history and past medical history as the patient couldn't communicate well with the medical stuffs due to his confusion or aphasia. I went in to do a mobility review on the patient. The patient couldn't perform any movements on command but is able to do them voluntarily. He also had some difficulties understanding my instructions. i was thinking at that time that he has both apraxia and aphasia. My supervisor asked me if there is any other pre existing conditions that could contribute to his current confusion and i looked at his PMH and he has dementia. My supervisor told me to keep my instruction short and simple with this patient. I managed to get his cooperation and was able to assess his mobility. When we left the patient, i had a discussion with my supervisor regarding how much of the patients presentation is dementia and how much of it was due to aphasia and apraxia. I then called his current hostel and i found out that he is from a dementia specific ward and he is usually good with following commands. The other thing that could contribute to his current confusion too was the fact that he is in a different environment than what he is use to. Since then i decided to keep my instruction short with him and that i don't have to explain much about what i am doing.
This has taught me that when it comes to patient with dementia, they sometimes could also present with apraxia and the fact that he is confused doesn't mean that he has aphasia. I have also learn to keep my instructions very simple with patients with dementia.