The Boston University researcher who announced Thursday that former Patriots fullback Kevin Turner died of a motor neuron disease caused by football-related chronic traumatic encephalopathy (CTE) issued a clarification Friday to address concerns from others in the medical community.
Dr. Ann McKee, the director of BU’s CTE Center, said in an interview that she stands by her discovery that CTE caused Turner’s fatal neurological disorder. But she said she did not mean to suggest that Turner and other deceased athletes whom she found to have been afflicted with motor neuron diseases triggered by CTE had been misdiagnosed by their clinicians as having amyotrophic lateral sclerosis (ALS), commonly known as Lou Gehrig’s disease.
In a news conference Thursday, McKee said of her findings in Turner’s case, “This is just another notch in the belt of getting to the bottom of this, which is, this is not ALS, folks, this is CTE.’’
McKee, a neuropathologist and leading CTE researcher, said Thursday that her postmortem autopsy of Turner’s brain and spinal cord showed that he died of a motor neuron disease that was similar but distinct from ALS.
She described her findings as “the best circumstantial evidence we will ever get that this ALS-type of motor neuron disease is caused by CTE.’’
The discovery represented another possible setback for the NFL, which is fighting the perception that its violence has caused debilitating and sometimes fatal disorders in many of its players. The league has reached a $1 billion settlement with former players who have possible brain damage.
McKee said Friday she had not heard from the NFL about her findings. However, she had fielded complaints from unspecified doctors who had diagnosed ALS in deceased athletes such as Turner.
McKee said she does not dispute the clinical diagnosis of ALS in Turner and others. Clinicians base ALS diagnoses on numerous tests, which can include muscle biopsies, MRIs, and spinal taps.
But she maintained that her pathological diagnosis, based on evidence that was not available to clinicians before Turner’s death, also is accurate.
“It’s a question of semantics because what I’m talking about is the pathological diagnosis, not the clinical diagnosis,’’ she said.
In the medical field, differences between clinical and pathological diagnoses are not uncommon. For instance, patients can be diagnosed with dementia, but they later may be found to have underlying diseases that broaden the understanding of their condition.
McKee said her findings, based on autopsy samples, might not represent “a smoking gun’’ in a court case.
“But in Kevin’s case, it’s as close to a smoking gun as you can get because of the extreme and very particular involvement of his motor system with CTE,’’ she said. “It was very obvious that it was not something you see in the most common form of ALS.’’
McKee has faced considerable criticism from advocates for the NFL and other contact sports over her studies through the years. She expressed a measure of regret that some clinicians were disturbed by her presentation and said she took no issue with their diagnoses, despite the differences from hers.
But she pledged to continue defending her findings.
“I’m making a stand here because there’s been resistance to a lot that we do and there has been resistance to this,’’ she said.
Bob Hohler can be reached at firstname.lastname@example.org.