Traumatic Encephalopathic Syndrome and CTE

The current definition for diagnosis of Chronic Traumatic Encephalopathy outlines a series of clinical symptoms that must be correlated with postmortem findings for a definitive diagnosis. The clinical symptoms are often gathered from family members and friends of the patient following his or her death, and must be matched with gross and microscopic changes to the brain at autopsy. The clinical presentation includes a wide range of symptoms in areas of mood, behavior, cognition, and movement.

Behavioral: explosivity, verbal and physical violence, loss of control, impulsivity, paranoia, and rage

Cognitive: deficits in memory, executive function, impaired attention

Motor: dysarthria, dysphagia, parkinsonism, coordination problems

These symptoms are then correlated with the pathological findings, that include deposition of hyperphosphorylated tau protein as neurofibrillary tangles, thorned astrocytes, and neurites in a unique pattern. The tau is characteristically found in a perivascular distribution, more often deep in cerebral sulci.

Because the definition of CTE is currently only applicable postmortem, it is important to establish a definition for the disease in living individuals in order to better classify the disease and identify patients in need of care. To distinguish a description of the clinical syndrome from that of the pathology-confirmed disease, the name “Traumatic Encephalopathy Syndrome” has been used. These criteria are meant to describe a clinical syndrome associated with a history of repeated brain trauma, and are not meant to predict neuropathological changes. A set of criteria proposed by Montenigro et al., 2014 outlines five general criteria, three clinical features, and nine supportive features for TES.

            The five general criteria for TES include a history of multiple impacts to the head, which can be defined as mild TBI or concussion, moderate/severe TBI (GCS score of less than 13), or subconcussive trauma. There must also be no other diagnosed neurological disorder in the individual. Clinical features must have been present for at least 12 months, with one of the “core” clinical features being present, and at least two of the supportive features.

            The clinical features of TES are the same as those described above for the clinical presentation of CTE and include changes in cognition, behavior, or mood, with a change in at least one of these areas being required for TES diagnosis.

 Finally, at least two supportive features must be present for a diagnosis of TES. These features are: impulsivity, anxiety, apathy, paranoia, suicidality, headache, motor signs, documented decline, and delayed onset.

            While there is significant overlap between portions of the diagnostic criteria for CTE and the definition of TES, these guidelines help to better elucidate a specific constellation of symptoms involved in TES and to define clinical findings of degenerative neuropathy prior to death and autopsy.