Smell and/or taste problems can also be caused by trauma to the head. Somewhere between 5 percent and 30 percent of head trauma patients will lose their sense of smell. Taste loss is estimated to occur in 0.5 percent of head trauma patients. Parosmias and dysgeusias may also occur. There is no known treatment for chemosensory problems caused by head trauma. Some patients will get better with time, although this may take years. Spontaneous recovery rates of 8 percent to 39 percent have been reported for smell function, with the majority of patients showing improvement within three months of injury.