Manicdepressionsymptom

My husband, age 39, was diagnosed with manic depression/bipolar disorder approximately two years ago. He suffers from recurrent bouts of depression and is currently in a depressive phase. He does not have very many manic phases at all. His short-term memory is getting progressively worse. Lately he cannot seem to remember how to get to places that he had just visited two or three days before. This has happened three times in the past week...