Tests and diagnosis

By Mayo Clinic Staff

There is currently no reliable way to diagnose CTE. A diagnosis requires evidence of degeneration of brain tissue and deposits of tau and other proteins in the brain that can be seen only upon inspection after death (autopsy). Some researchers are actively trying to find a test for CTE that can be used while people are alive. Others continue to study the brains of deceased individuals who may have had CTE, such as football players.

Eventually, the hope is to use a range of neuropsychological tests, brain imaging and biomarkers to diagnose CTE. In particular, imaging of amyloid and tau proteins will aid in diagnosis.

Neurological tests

Your doctor will check your neurological health by testing your:

  • Speech, language and cognition — including short- and long-term memory
  • Reflexes
  • Muscle tone and strength
  • Ability to get up from a chair and walk across the room
  • Sense of sight and hearing
  • Coordination
  • Balance

Brain-imaging tests

Brain-imaging technology is currently used to diagnose mild traumatic brain injury. Some of the following technologies might be used for CTE diagnosis in the future.

Magnetic resonance imaging (MRI). An MRI uses a strong magnetic field to detail brain images. Researchers believe that as the following specialized MRI tests improve, they may be able to help diagnose CTE.

  • Susceptibility-weighted imaging (SWI) is a type of MRI that shows tiny bleeds (hemorrhages) that result from injury to the central nervous system.
  • Diffusion tensor imaging (DTI) is a type of MRI that reveals the movement of water and the path of white matter in the brain, which can show brain abnormalities. It shows promise for detecting CTE, but needs to become more accurate and precise.
  • Magnetic resonance spectroscopy (MRS) is similar to MRI but may be able to provide greater details about neurological damage.

Positron emission tomography (PET). A PET scan uses a low-level radioactive tracer that is injected in a vein. Then, a scanner tracks the tracer's flow through the brain. Researchers are actively working to develop PET markers to detect tau abnormalities associated with neurodegenerative disease.

The goal is to develop a marker to identify the tau pathology of CTE in people who are living.

Researchers are using various substances that bind to tau and other proteins on PET scans. These PET scans are in the research phase and not available for clinical testing.

Event-related potentials (ERPs) and quantitative EEG. These noninvasive tests use electroencephalography (EEG), in which a mesh cap covered with electrodes is placed on a person's head. It allows doctors to detect, record and analyze brain waves, which may find brain changes that result from multiple traumatic brain injuries.

Single-photon emission computerized tomography (SPECT). SPECT is an imaging test used to diagnose types of dementia. Studies are needed to show whether SPECT can tell CTE from Alzheimer's disease or other neurodegenerative diseases.

Other tests

There's been little research on plasma or cerebral spinal fluid to diagnose the long-term disease processes of CTE. Some biomarkers that are used in Alzheimer's disease research may be useful for CTE because the conditions are similar. These biomarkers would need to identify brain degeneration from CTE separately from the original brain trauma.

April 20, 2016