Sundowning is a term for increased confusion and restlessness that occur around the same time everyday. Typically this syndrome happens in individuals with dementia or Alzheimer’s disease. Other related behaviors are  wandering, verbal outbursts, and increased agitation that may appear to be random but on closer examination are related to the thought processing of the individual.
In fact, it is important to provide a consistent routine, a calming environment, and to engage in activities that can promote relaxation. Lastly, talk to your doctor to rule out any other causes of agitation such as pain, medication side effects or infection.