What cognitive domain primarily impacted Brennan in his assessment for chronic traumatic encephalopathy?

The correct answer focuses on the cognitive domain of problem-solving, which is particularly affected in individuals with chronic traumatic encephalopathy (CTE). CTE is a progressive neurodegenerative disease that often arises following repeated head trauma, such as concussions. One of the hallmark symptoms of CTE is a decline in executive functions, which include problem-solving abilities, planning, and decision-making.

In cases of CTE, individuals may face difficulties in processing information, organizing thoughts, and developing solutions to everyday problems. This impairment can significantly impact a person's ability to function effectively in various aspects of life, particularly in roles requiring critical thinking and adaptability.

In contrast, while long-term memory, language skills, and social interactions can also be affected in individuals with CTE, the core issue often lies within executive functioning, with problem-solving being a key component. This makes problem-solving the most appropriate cognitive domain to identify regarding Brennan's assessment for CTE.