Misdiagnosis and the brain
The Frontal Assessment Battery (FAB) is a test that was developped to determine if the patient was affected by a frontal lobe injury and to see the degree of impairment. Recently, a paper published by Chapatos and Petrides (2013) (http://www.ncbi.nlm.nih.gov/pubmed/24030949) revisted the reliability of this test. Their reasoning behind this revisitation was simple: the patients in this study did not sustain injuries that were solely retricted to the frontal lobe. All of the patients’ injuries were involved the frontal lobe as well as the basal ganglia. Chapados and Petrides (2013) claim that the connections to the basal ganglia influenced the data and thus rendered the Frontal Assessment Battery unreliable with respect to diagnosis (or misdiagnosing) patients who has injuries truly restricted to the frontal lobe. Chapados and Petrides (2013) assessed patients at the Montreal Neurological Institute. Some patients had strictly frontal lobe injuries and others had injuries implicating both the frontal lobe and the basal ganglia. As they hypothesized, the patients were correctly identified as having frontal injuries only if the basal ganglia played a part. However, for the patients with no basal ganglia implication were not picked up by the battery. This begs the question: how many people actually sustained strictly frontal injuries but never received a diagnosis nor treatment? For years this battery was used and although some patients with frontal injuries were accurately diagnosed, many fell through the cracks because this test was not neuroanatomically reliable. This just goes to show the importance of neuroanatomy when dealing with brain injury patients but it also goes to show the importance of reliability within constructs and the test items used.
Because of lack of reliability, you are not only collecting flawed data but you may also be affecting the lives of others. In the case of the FAB, peope with brain injuries — that alter their cognitive functioning and affect their daily lives — were walking around without a proper diagnosis or treatment to rehabilitate their injury. If you don’t know what you’re actually measuring nor what you’re looking at when you gather the data, how can you expect to productively use this in the treatment of clinical patients? This is the question that we ask ourselves time and time again: is what I’m meauring actually what is supposed to measured? Although we are aware that this question must be asked, it is clear that it is not always answered.
~CaS
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