National Institute of Neurological Disorders and Stroke Consensus Diagnostic Criteria for Traumatic Encephalopathy Syndrome

Abstract

Objective: To develop evidence-informed, expert consensus research diagnostic criteria for traumatic encephalopathy syndrome (TES), the clinical disorder associated with neuropathologically diagnosed chronic traumatic encephalopathy (CTE).

Methods: A panel of 20 expert clinician-scientists in neurology, neuropsychology, psychiatry, neurosurgery, and physical medicine and rehabilitation, from 11 academic institutions, participated in a modified Delphi procedure to achieve consensus, initiated at the First National Institute of Neurological Disorders and Stroke Consensus Workshop to Define the Diagnostic Criteria for TES, April, 2019. Before consensus, panelists reviewed evidence from all published cases of CTE with neuropathologic confirmation, and they examined the predictive validity data on clinical features in relation to CTE pathology from a large clinicopathologic study (n = 298).

Results: Consensus was achieved in 4 rounds of the Delphi procedure. Diagnosis of TES requires (1) substantial exposure to repetitive head impacts (RHIs) from contact sports, military service, or other causes; (2) core clinical features of cognitive impairment (in episodic memory and/or executive functioning) and/or neurobehavioral dysregulation; (3) a progressive course; and (4) that the clinical features are not fully accounted for by any other neurologic, psychiatric, or medical conditions. For those meeting criteria for TES, functional dependence is graded on 5 levels, ranging from independent to severe dementia. A provisional level of certainty for CTE pathology is determined based on specific RHI exposure thresholds, core clinical features, functional status, and additional supportive features, including delayed onset, motor signs, and psychiatric features.

Conclusions: New consensus diagnostic criteria for TES were developed with a primary goal of facilitating future CTE research. These criteria will be revised as updated clinical and pathologic information and in vivo biomarkers become available.

Figure 1. Stepwise Process for Using the NINDS Consensus Diagnostic Criteria for Traumatic Encephalopathy Syndrome

The first step is to determine whether the individual meets criteria for substantial exposure to repetitive head impacts (table 1). If yes, core clinical features (table 2) are determined, and if criteria are met, those features must be not fully accounted for by other disorders (table 3). If yes, the TES criteria are met and the final step is to determine level of functional dependence/dementia (table 4). NINDS = National Institute of Neurological Disorders and Stroke; TES = traumatic encephalopathy syndrome.

Figure 2. Flow Diagram for Determining Provisional Levels of Certainty for CTE Pathology for Research Purposes

Specific criteria are provided in tables 1–6. These provisional criteria are not meant for clinical diagnostic purposes. Rather, they are meant for research settings by providing a description of the level of certainty (i.e., diagnostic specificity) that an individual's clinical features are due to underlying p-tau pathology meeting the current neuropathologic diagnostic criteria for CTE. CTE = chronic traumatic encephalopathy.