Regular Research Article
PET Scanning of Brain Tau in Retired National Football League Players: Preliminary Findings

https://doi.org/10.1016/j.jagp.2012.11.019Get rights and content

Objective

Mild traumatic brain injury due to contact sports may cause chronic behavioral, mood, and cognitive disturbances associated with pathological deposition of tau protein found at brain autopsy. To explore whether brain tau deposits can be detected in living retired players, we used positron emission tomography (PET) scans after intravenous injections of 2-(1-{6-[(2-[F-18]fluoroethyl)(methyl)amino]-2-naphthyl}ethylidene)malononitrile (FDDNP).

Methods

Five retired National Football League players (age range: 45 to 73 years) with histories of mood and cognitive symptoms received neuropsychiatric evaluations and FDDNP-PET. PET signals in subcortical (caudate, putamen, thalamus, subthalamus, midbrain, cerebellar white matter) and cortical (amygdala, frontal, parietal, posterior cingulate, medial and lateral temporal) regions were compared with those of five male controls of comparable age, education, and body mass index.

Results

FDDNP signals were higher in players compared with controls in all subcortical regions and the amygdala, areas that produce tau deposits following trauma.

Conclusions

The small sample size and lack of autopsy confirmation warrant larger, more definitive studies, but if future research confirms these initial findings, FDDNP-PET may offer a means for premorbid identification of neurodegeneration in contact-sports athletes.

Section snippets

Methods

Neuropsychiatric evaluations were performed on five retired players aged 45 years or older who were recruited for this study because of a history of cognitive or mood symptoms. Through organizational contacts, NFL retirees with MCI-like symptoms were referred for testing. Of the 19 potential volunteers, 14 did not participate because of non-response or disinterest (N = 10), age (too young; N = 2), or medical illness (N = 2).

Subjects had screening laboratory tests and structural imaging scans

Results

The players represented a range of positions and diagnoses (linebacker with MCI; quarterback with normal aging; guard with dementia/depression; defensive lineman with MCI/depression; center with MCI) and played professionally from 10–16 (median, 14) years (Fig. 1). Players and controls were comparable in age (median age for players [controls]: 59 [60]; range: 45–73 [45–66], BMI (players [controls]: 32 [34], 28–42 [28–38]), years of education (players [controls]: 17 [15], 15–18 [13–22]), race (4

Discussion

These initial FDDNP-PET findings in retired NFL players with histories of cognitive and mood symptoms demonstrate high signals in the amygdala and subcortical regions compared with controls. Although the subject groups were matched for important variables, such as age, BMI, and educational achievement, these preliminary results need interpretation with caution given the small sample size and multiple uncorrected statistical comparisons. Also, not all subjects had MRI scans for co-registration

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