Repeated head injury that might be incurred by activities such as boxing can lead to what is called Dementia Due to Head Trauma(DDHT). These brain injuries are also diagnosed as progressive dementia. A single blow to the head can also cause DDHT injury, but a single blow to the head is more often than not, not a progressive dementia. The main requisite to diagnose a DDHT injury is the presentation of features of dementia that can be traced to onset beginning with the head trauma.

The area of the brain that has been traumatized and the extent to which that part of the head has been struck will also determine the type of sensory impairments and behavioral disturbances that might be displayed by the patient.

A common symptom is referred to as posttraumatic amnesia which might progress to persistent memory impairment. There are other behavioral symptoms that might present themselves along with or without the loss of physical motor skills. The most common symptoms of traumatic brain injury are aphasia, attention deficit problems, irritability, anxiety, depression, apathy, intermittent disruptive disorder, and changes in the patient's personality.

If the dementia is non progressive, the individual with the single blow to the head will present with identifiable symptoms that will remain with little chance of regaining the lost motor skills or the posttraumatic memories. If the dementia is progressive, the patient will follow the pattern of a typical dementia patient and his neurological functioning will continue to deteriorate.