BOSTON—Proposed diagnostic criteria for prob- able or possible chronic traumatic encephalopathy (CTE), a progressive neurodegenerative disease
associated with repetitive brain trauma, include a
history of head impacts and various core clinical and
The preliminary criteria, which were presented by
Andrew Budson, MD, Professor of Neurology at Boston
University School of Medicine, at the 69th Annual Meeting of the American Academy of Neurology, primarily
were designed for research purposes, but can serve as
a guide for neurologists for the diagnosis of traumatic
encephalopathy syndrome. CTE is a neuropathologic
diagnosis, whereas traumatic encephalopathy syndrome
is a clinical diagnosis. In addition to presenting the general criteria, Dr. Budson shared diagnostic subtypes, potential biomarkers, and treatment options.
There are five general criteria that patients must meet
to receive a diagnosis of traumatic encephalopathy syndrome, said Dr. Budson. First, there must be a history
of impacts to the head based on types of injuries (eg,
mild or severe traumatic brain injury, concussions, or
subconcussive trauma) and sources of exposure, such
as military service or involvement in contact sports for
a minimum of six years, including at least two years at
the college level or higher.
Second, patients must not have another neurologic
disorder that likely accounts for the clinical features.
Third, clinical features must be present for at least
12 months. The fourth requirement is that at least one
core clinical feature (ie, cognitive, behavioral, or mood
features) must be present and considered a change
from baseline. Finally, at least two of nine supportive
features must be present.
Core Clinical and Supportive Features
Of the core clinical features, difficulties in cognition must
be reported by the patient, an informant, or a clinician
and substantiated by standardized tests. Core behavioral
clinical features include emotionally explosive behavior
or physical and verbal abuse. Core mood clinical features
include feeling overly sad, depressed, or hopeless.
In addition to core clinical features, two of the following supportive features must be present: impulsivity,
anxiety, apathy, paranoia, suicidality, headache, motor
signs (eg, dysarthria, dysgraphia, or other features of
parkinsonism), documented decline for at least a year,
or delayed onset of clinical features after a significant
head impact exposure (usually at least two years).
Patients may have one of four possible traumatic encephalopathy syndrome diagnostic subtypes. A behavioral/
mood variant is more common among younger patients,
whereas a cognitive variant is more common in older
populations, said Dr. Budson. Patients also may have
a mixed variant or dementia. Patients with the dementia subtype must have a progressive course of cognitive
core clinical features, with or without behavior or mood
features. In addition, patients with dementia must have
cognitive impairment that interferes with their ability to
function independently during normal daily activities.
Biomarkers and Treatment
Cavum septum pellucidum, cavum vergae, or fenestrations on neuroimaging are potential CTE biomarkers,
How Can Neurologists Diagnose
Traumatic Encephalopathy Syndrome?
Explosive behavior and anxiety are among the features that support a diagnosis of
possible or probable CTE.
Normal beta amyloid CSF levels,
elevated CSF p-tau/tau ratio, and
cortical atrophy beyond that expected
for age could be signs of CTE.