Health and Psychology

What's the difference between testing in neuropsychology and psychology?

I met a psychologist who does psychological testing that includes some neuropsychological instruments.  I've also met neuropsychologists who are primarily using psychological tests as neuropsychological instruments.  So here's the difference.  A neuropsychologist can relate brain functioning to testing. 

A standard psychological test is the Wechsler Adult Intelligence Scale (WAIS).  It's part of the Wechsler series of testing, which includes memory (Wechsler Memory Scales) and achievement (Wechsler Individual Achievement Test) in addition to intellectual processes.  When administered, scored and interpreted by a psychologist, this test provides raw and scaled scores and index scores.  A variety of information is collected on Verbal Comprehension, Perceptual Reasoning, Working Memory, and Processing Speed.  Computerized reports can be generated that will provide between 10 to 20 pages of scientifically valid, empirically based data on all aspects of intellectual functioning.

When the same test is administered by a neuropsychologist in addition to all of the above data is information on how that all translates to brain functioning.  Using the exact same test I look at estimated functioning of cognition prior to how the individual is testing now.  I look for things that suggest brain damage specifically (pathognomic indicators).  I look to see if there are psychological factors that are noted in off-hand comments being made by the person I'm examining.  ("Oh I was never good at this kind of thing."  Or "I think this is hard, can anyone do this?" Or "I don't understand how to do this.")

I also notice things that tell me how someone thinks about the test and how their brain works.  Do they consistently ignore materials I place on their right or left side?  Do they have a systematic trial and error method of responding to the materials or are they making guesses?  If they miss items and recognize their limitations, do they get overwhelmed or shrug it off?  Do they notice errors at all or do they think what they did was correct?

Little things become important.  When using both hands are the movements symetrical or is one slower?  Is there a tremor when writing or even just holding a pencil?  Are they sitting upright or leaning to one side?  Do they tilt their head when working? Squint their eyes?  Does their coloring change?  Their respiration? Do they stop responding and seem to get lost then seem to return? 

Hundreds of little observations, perhaps thousands, in the course of an hour or so.  Even if I use a computer to score the data, I have to add all the observations that go into doing the testing.  Then I have to tie all those observations into brain function.

A graduate student of mine commented that she holds her pencil between her thumb and third finger "because it's more comfortable."  She's taken a WAIS as part of her training.  But now she's learning neuropsychology.  So the class talked about cortical functioning of fine motor skills and the distinction between pencil grip, hand coordination, fingering of small items, handedness, and gross motor skills of arm movement, fluidity of hand motion, the distinction between nerves coming from the spinal cord along the hands and arms and the movements generated in the brain down those same brain pathways.  As we talked and evaluated the student and class came to realize how much brain was involved in that single comment. That little "just feels more comfortable" grip of a pencil.  There was some gross motor involvement, memory involvement, directional sense, and sensory experiences. 

Tying all those together and testing the theories of brain functioning to show how they all relate, differentiates a neuropsychologist from a psychologist.  Even when neuropsychologists and psychologists do the exact same tests in the exact same way we get different data.