Difference between focal or diffuse brain injury

Dr. Lange provided a brief overview of the developmental history of clinical neuropsychology. She mentioned that neuropsychological testing evolved to assess individuals with focal acquired brain injuries for diagnosis and management. She distinguished acquired brain injuries that occur after birth from those that an individual is born with, congenital or genetic brain conditions. Before the advances made in neuroimaging technology such as CAT and MRI scans, neuropsychology was used to pinpoint the area of dysfunction in the brain. However, damage to the brain is not always focal, but can be diffuse in nature. Dr. Lange explained that neuropsychological assessment of diffuse brain injuries, affecting many interconnecting areas of the brain, is difficult as the measures were developed to reveal dysfunction in specific brain regions. These conditions include Multiple Sclerosis, Parkinson's disease and Chronic Fatigue Syndrome.

She noted that appropriate interpretation of test data from individuals with these conditions requires a significant degree of interpretation and knowledge by the practitioner. If a neuropsychologist has not had the opportunity to deal with patients with an illness that affects the brain in a diffuse and subtle manner, such as CFS, they might not be sensitive to the type of cognitive dysfunctions seen in these patients. Patients need to find neuropsychologists who are sensitive and knowledgeable about these issues. When a patient is looking for a neuropsychologist, he or she must find someone who is knowledgeable about CFS and FM. Patients must interview neuropsychologists to determine the best candidate, because neuropsychological testing is expensive. CFS patients have deficits. A knowledgeable neuropsychologist must look at the numbers across the different cognitive domains for an appropriate reflection of the cognitive profile with its strengths and weaknesses.