About Dr. Klein Gad E. Klein, Ph.D., is a neuropsychologist who specializes in the cognitive aspects of various neurological disorders including epilepsy, movement disorders such as Parkinson’s disease, as well as brain tumors and dementia. He also evaluates the cognitive and behavioral sequelae of traumatic brain injury and stroke. Dr. Klein is also an expert in advanced neuro-imaging techniques such as functional MRI, as well as the intracarotid amobarbital test (Wada test) and electrocortical stimulation mapping.