My focus within clinical psychology is clinical neuropsychology. In this field of study, we attempt to understand higher level cognitive processes (like attention, memory, speeded information processing, etc.) in the brain, particularly in individuals with neurological diseases. One area I have focused on is studying patients with multiple sclerosis (MS). MS is a disorder of the central nervous system that results in the destruction of the white matter (in particular, the myelin) in the brain. This destruction is thought to occur through some autoimmune process but the mechanism underlying that process is currently not well understood. MS typically strikes people in their 20's and 30's, just as they are starting their careers/families, and patients typically live many years with their symptoms, so it is a particularly devastating disease. It affects women more than men by about a 2:1 ratio, is more common in geographical regions farther away from the equator, and tends to differentially affect individuals of Western/Northern European ancestry.

A thread that has organized my research program involves the study of secondary factors that may influence cognitive performance in MS patients. On the surface, it may seem relatively simple to administer a neuropsychological test to measure a particular cognitive function (e.g., memory, information processing speed), see how patients perform relative to normative data or controls, and draw conclusions about patients’ cognitive profile based upon their relative performance. In actual practice, interpreting neuropsychological tests, especially in neurological patients (like those with MS), is extremely challenging. One reason for this is that multiple non-cognitive factors can interfere with a patient’s performance on these tests. For example, many neurological patients suffer from depression, and depression has been shown to interfere with performance on many types of effortful cognitive tasks. Thus, a neurological patient could perform poorly on a demanding set of cognitive tasks not because of any primary cognitive difficulty emanating from the neurological condition, but because of the secondary effects of depression.

Much of my research program with my students at Penn State has focused on developing a better understanding of the relationship between depression and cognitive dysfunction in MS. More generally, my students and I have studied a number of factors associated with depression in MS. A model of depression guiding but also formulated by our research is illustrated and described here. We have also been exploring the influence of another possible secondary factor involved in cognitive performance in MS patients—oral motor speed. Our ongoing work in this domain is described in more detail here. We have also begun exploring the relationship between another secondary influence on cognitive functioning, fatigue, and some of our initial work in this domain is described here. Besides our work in multiple sclerosis, I oversee the Neuropsychology of Sports-Related Concussion Program. For a more detailed description of this program click here.