Chronic Traumatic Encephalopathy (CTE) in 2026: What We Know, What We Don’t, and What Families Should Understand

Brain Trauma & Recovery
Anton Ostashko, MD·Last medically reviewed July 10, 2026

Overview

Chronic traumatic encephalopathy (CTE) is a neurodegenerative tauopathy associated with exposure to repetitive head impacts. It has been identified most often in people with years of contact or collision sport participation and in some people with military, occupational, or interpersonal-violence exposure. The field is advancing quickly, but its most important limitation has not changed: CTE is a neuropathologic diagnosis made by examining brain tissue after death. There is currently no validated scan, blood test, cerebrospinal-fluid test, or office examination that can confirm CTE in a living person.21

The clinical syndrome studied during life is called traumatic encephalopathy syndrome (TES). TES and CTE are not interchangeable. A person may have symptoms compatible with TES for reasons other than CTE, and a person with low-stage CTE pathology may not have had recognizable symptoms.187

The most important updates through July 10, 2026 are:

  • Advanced CTE pathology has a clearer association with dementia. In a 2026 clinicopathologic study, stage IV CTE was associated with about 4.5-fold higher odds of dementia and stage III with about 2.1-fold higher odds compared with no CTE, after accounting for several other neuropathologies. Stages I and II were not associated with dementia or cognitive symptoms in that analysis.711
  • Mood and behavior should not be treated as a specific “signature” of CTE. The same 2026 study did not find an association between CTE stage and informant-rated mood or behavioral symptoms. Irritability, impulsivity, depression, anxiety, substance use, and suicidality remain clinically important, but they are nonspecific and often have multiple causes.7
  • Cumulative exposure matters more than a simple concussion count. Brain-bank studies across American football, ice hockey, and rugby support dose-response relationships with years of play, while also being unable to estimate population prevalence because brain donation is highly selected.456
  • TES criteria remain research criteria. They can organize a careful evaluation but should not be used to tell a living patient that CTE has been proven.18
  • Conference information must be labeled appropriately. This article incorporates themes from the February 2026 Global CTE Summit attended by the author, but unpublished presentations are treated as conference context—not established evidence—unless independently supported by peer-reviewed or official sources.910

Evidence cutoff and conference provenance: Evidence was reviewed through July 10, 2026. Conference-derived material is identified as such. Recorded or transcribed remarks can be valuable for understanding expert discussion, but they are not equivalent to peer-reviewed results, regulatory decisions, or consensus guidelines.

CTE and TES: One Pathology, One Clinical Research Syndrome

TermWhat it meansCan it be confirmed during life?
CTEA specific pattern of phosphorylated tau around small blood vessels at the depths of cortical sulci, diagnosed by neuropathologic examination.No. Definite diagnosis currently requires postmortem tissue.
TESA research-defined clinical syndrome involving substantial repetitive-head-impact exposure plus progressive cognitive impairment and/or neurobehavioral dysregulation, after other causes are considered.A clinician may judge that the research syndrome is present, but this does not prove CTE pathology.
Persistent post-concussion symptomsSymptoms continuing after a concussion, often involving headache, dizziness, sleep, mood, vision, cognition, or neck pain.Diagnosed clinically; it is not the same as CTE or TES.

The 2021 NINDS TES criteria require substantial exposure to repetitive head impacts, core cognitive impairment and/or neurobehavioral dysregulation, a progressive course, and exclusion of another disorder that fully explains the presentation. They also provide provisional levels of certainty that TES is related to CTE. The authors explicitly developed these criteria for research and cautioned against using them as a definitive clinical test.1

That caution is essential. Common conditions—including depression, anxiety, post-traumatic stress disorder, sleep apnea, chronic pain, medication effects, alcohol or substance use, vascular brain disease, Alzheimer’s disease, Lewy body disease, and frontotemporal degeneration—can produce overlapping symptoms. A responsible evaluation looks for these conditions rather than attributing every problem to past sport or military exposure.

What Makes the Pathology Distinctive?

The pathognomonic CTE lesion is an irregular accumulation of phosphorylated tau in neurons, with or without astrocytes, around small blood vessels at the depths of cortical sulci. This location and pattern differ from the typical distribution of Alzheimer-type tau. Cryo-electron microscopy has also shown that CTE tau filaments have a molecular fold distinct from those in Alzheimer’s disease, supporting CTE as a separate tauopathy.23

Neuropathologists stage CTE from I to IV. Early stages contain limited cortical lesions; later stages involve broader cortical and subcortical regions and may be accompanied by atrophy. Staging describes pathology—not an inevitable clinical trajectory. The 2026 clinicopathologic analysis strengthened the association between high-stage CTE and dementia while underscoring uncertainty about the clinical meaning of low-stage disease.7

Other pathologies can coexist. Alzheimer-type amyloid and tau, Lewy bodies, vascular injury, TDP-43 pathology, and hippocampal sclerosis may all contribute to symptoms. Finding CTE at autopsy does not mean that every symptom was caused by CTE alone.

Repetitive Head Impacts and the Dose-Response

Current evidence points to cumulative repetitive head impacts—not merely the number of diagnosed concussions—as the central exposure. Many impacts that do not cause immediate symptoms still contribute to total biomechanical burden. In selected brain-donation cohorts, more years of American football, ice hockey, or rugby participation have been associated with greater odds or severity of CTE pathology.456

What these studies cannot tell us: Brain banks are not random samples. Families are more likely to donate when a person had concerning symptoms, and exposure histories differ. The studies demonstrate pathology and dose-response relationships in selected cohorts; they do not establish the probability that any particular former athlete has CTE.

Individual susceptibility almost certainly varies. Age at first exposure, total years, position, impact intensity, recovery time, genetics, vascular health, other injuries, and coexisting disease may all matter. No current calculator can convert an exposure history into a reliable personal CTE probability.

Symptoms: What Is Known and What Is Not

People seeking evaluation may report memory loss, slowed thinking, poor planning, impulsivity, irritability, emotional lability, depression, anxiety, sleep disturbance, headache, imbalance, parkinsonism, or reduced day-to-day function. These symptoms are real and deserve care. None is specific to CTE.

Cognition

The strongest clinicopathologic signal is now for cognitive impairment and dementia in advanced CTE. Memory and executive function are commonly emphasized, but a person’s pattern should be measured with history, functional assessment, and neuropsychological testing rather than inferred from exposure alone.71

Mood and behavior

The TES research criteria include neurobehavioral dysregulation—such as explosiveness, impulsivity, emotional lability, and loss of behavioral control—as a possible core feature. Yet the 2026 autopsy study did not find mood or behavior scales to be associated with CTE stage.17 This means clinicians should treat mood and behavioral symptoms urgently when necessary, while avoiding the claim that they prove CTE.

Motor and other neurological symptoms

Gait change, tremor, slowness, falls, speech change, and swallowing difficulty may occur in people with substantial head-impact exposure, but they broaden the differential diagnosis. Parkinson’s disease, progressive supranuclear palsy, multiple system atrophy, stroke, neuropathy, cervical myelopathy, medication effects, and other disorders may be more likely explanations.

How a Living Patient Is Evaluated

The goal is not to “test for CTE.” It is to characterize the problem, identify treatable contributors, assess safety, and determine whether another neurological or psychiatric disorder better explains the symptoms.

  1. Exposure history: sports, military, blast, occupational, assault, and intimate-partner-violence exposure; duration and intensity; diagnosed concussions; and ongoing risk.
  2. Symptom timeline: which change came first, whether symptoms are progressive or fluctuating, and how work, finances, driving, medications, and relationships are affected.
  3. Neurological and behavioral examination: cognition, eye movements, gait, coordination, parkinsonism, speech, mood, impulse control, and judgment.
  4. Neuropsychological testing: useful when objective characterization, differential diagnosis, or a baseline is needed.
  5. Targeted testing: laboratory tests, sleep evaluation, MRI, and—in selected cognitive cases—Alzheimer biomarkers or other studies chosen to answer a specific question.
  6. Collateral history: input from a trusted family member or care partner is often essential because loss of insight can accompany cognitive or behavioral disorders.

What imaging and biomarkers can—and cannot—do

  • MRI can identify stroke, tumor, hydrocephalus, prior hemorrhage, white-matter disease, and patterns of atrophy. Findings such as a cavum septum pellucidum are not specific enough to diagnose CTE.
  • Amyloid biomarkers may support or argue against Alzheimer’s disease. A negative amyloid test does not establish CTE.
  • Tau PET tracers developed for Alzheimer’s disease do not currently provide a validated individual diagnosis of CTE.
  • Blood or CSF markers of axonal injury may be useful in acute or research settings, but no marker confirms CTE or predicts who will develop it.

Treatment: Address the Person, Not an Unproven Label

No medication has been shown to remove CTE tau or halt CTE progression. Treatment is nevertheless meaningful because many drivers of disability are modifiable.

  • Depression, anxiety, irritability, and trauma symptoms: psychotherapy, psychiatric care, and carefully selected medication when appropriate.
  • Sleep: treat insomnia, sleep apnea, REM sleep behavior disorder, circadian disruption, and substance-related sleep problems.
  • Headache, dizziness, pain, and vestibular symptoms: diagnosis-specific treatment and rehabilitation.
  • Cognition and function: compensatory strategies, occupational therapy, structured routines, medication review, and safety planning.
  • Vascular health: control blood pressure, diabetes, lipids, smoking, and physical inactivity.
  • Family support: caregiver education, behavioral plans, financial and driving assessment, and clear crisis instructions.

Urgent safety: New suicidal thoughts, threats, violence, inability to care for oneself, rapidly worsening confusion, seizures, or focal neurological deficits require urgent evaluation. In the United States, call or text 988 for a mental-health crisis and call 911 for imminent danger or a medical emergency.12

Prevention Is the Most Actionable Message

The February 2026 Global CTE Summit centered on caring for people with suspected CTE and on prevention, diagnostics, public health, and family experience.910 The most defensible prevention principle is to reduce cumulative head-impact exposure:

  • Delay or limit collision exposure in children when feasible.
  • Reduce contact during practice and enforce sport-specific safety rules.
  • Remove athletes immediately when concussion is suspected and use a graduated return process.
  • Do not normalize playing through neurological symptoms.
  • Improve informed consent so athletes and families understand both known risks and uncertainty.
  • Prevent additional impacts while the brain is recovering.

Helmets and other equipment can reduce some injuries, particularly skull and facial injury, but no helmet has been proven to eliminate concussion or CTE risk.

What Patients and Families Should Take Away

  • A history of repetitive head impacts is a reason for thoughtful evaluation—not for self-diagnosis.
  • Definite CTE cannot currently be diagnosed during life.
  • Advanced CTE is associated with dementia, but low-stage disease and individual prognosis remain uncertain.7
  • Mood and behavioral symptoms deserve treatment but are not specific evidence of CTE.
  • Other neurological, psychiatric, sleep, pain, and substance-related conditions may be treatable and should be actively sought.
  • Reducing future head impacts remains worthwhile at every age.

Bottom line: CTE is real, but certainty during life remains limited. The medically responsible approach is to separate pathology from syndrome, communicate uncertainty honestly, treat symptoms and comorbidities aggressively, protect safety, support families, and reduce further repetitive head impacts.

At Los Altos Neurology, evaluation of former athletes and others with repetitive-head-impact exposure focuses on cognition, behavior, mood, sleep, motor function, and everyday safety, while using imaging and biomarkers only when they answer a clearly defined differential-diagnosis question.

References

  1. Katz DI, Bernick C, Dodick DW, et al. Neurology. 2021;96:848-863. NINDS consensus diagnostic criteria for traumatic encephalopathy syndrome.
  2. Bieniek KF, Cairns NJ, Crary JF, et al. J Neuropathol Exp Neurol. 2021;80:210-219. Second NINDS/NIBIB consensus neuropathologic criteria for CTE.
  3. Falcon B, Zivanov J, Zhang W, et al. Nature. 2019;568:420-423. Cryo-EM structures of tau filaments from chronic traumatic encephalopathy.
  4. Mez J, Daneshvar DH, Abdolmohammadi B, et al. Ann Neurol. 2020;87:116-131. Duration of American football play and chronic traumatic encephalopathy.
  5. Abdolmohammadi B, et al. JAMA Netw Open. 2024;7:e2447731. Years of ice hockey play and chronic traumatic encephalopathy.
  6. Stewart W, et al. Acta Neuropathol. 2024;147:31. Chronic traumatic encephalopathy in former elite rugby union players.
  7. Alosco ML, et al. Alzheimer’s & Dementia. 2026. doi:10.1002/alz.71032. CTE neuropathology alone is associated with dementia and cognitive symptoms.
  8. Mez J, et al. Alzheimer’s Dement. 2023;19:528-541. Clinical validity of traumatic encephalopathy syndrome criteria.
  9. Concussion & CTE Foundation, Boston University CTE Center, and UCSF Memory and Aging Center. February 2, 2026. Global CTE Summit 2026 agenda.
  10. Boston University Chobanian & Avedisian School of Medicine Continuing Education. 2026. The Global CTE Summit—course overview.
  11. National Institutes of Health. 2026. Severe CTE clearly linked to dementia.
  12. U.S. 988 Suicide & Crisis Lifeline. 988 Suicide & Crisis Lifeline.

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