The goals of the neurological examination are several:
- For patients presenting with symptoms suggestive of a neurological problem, the examination should:
- Determine, on the basis of an organized and thorough examination, whether in fact neurological dysfunction exists.
- Identify which component(s) of the neurological system are affected (e.g. motor, sensory, cranial nerves, or possibly several systems simultaneously).
- If possible, determine the precise location of the problem (e.g. peripheral v central nervous system; region and side of the brain affected etc.).
- On the basis of these findings, generate a list of possible etiologies. Unlikely diagnoses can be excluded and appropriate testing (e.g. brain and spinal cord imaging) then applied in an orderly and logical fashion.
- Screening for the presence of discrete abnormalities in patients at risk for the development of neurological disorders. This is appropriate for individuals who have no particular subjective symptoms suggestive of a neurological problem, yet have systemic illnesses that might put them at risk for subtle dysfunction. Diabetic patients, for example (particularly those with long standing poor control), may develop peripheral nerve dysfunction. This may only be detected through careful sensory testing (see below under Sensory Testing), which would have important clinical implications.
- Cursory screening/documentation of baseline function for those who are otherwise healthy. In patients with neither signs nor risk factors for neurological disease, its unlikely that the detailed exam would uncover occult problems. Simply observing the patient during the course of the usual H&P (i.e. watching them walk, get up and down from the exam table, etc.) may well suffice. Many examiners incorporate some aspects of the neuro exam into their standard evaluations. Cranial Nerve testing, for example, can be easily blended into the Head and Neck evaluation. Deciding what other aspects to routinely include is based on judgment and experience.
The major areas of the exam, covering the most testable components of the neurological system, include:
- Mental status testing
- Cranial Nerves
- Muscle strength, tone and bulk
- Cerbellar Function
- Sensory Function
Real and imagined problems with the neurological examination:
The neurological examination is one of the least popular and (perhaps) most poorly performed aspects of the complete physical. I suspect that this situation exists for several reasons:
- This exam is perceived as being time and labor intensive.
- Students and house staff never develop an adequate level of confidence in their ability to perform the exam, nor in the accuracy of their findings. This, in turn, probably translates into poor performance later in their careers.
- Exam findings are often quite subjective.Thus, particularly when the examiner does not have confidence in their abilities (see above), interpretation of the results can be problematic.
- Understanding/Interpretation of some neurological findings requires an in depth understanding of neuroanatomy and pathophysiology. As many clinicians do not see a large number of patients with neurological disorders, they likely maintain a limited working understanding of this information.
- There is an over reliance on the utility of neuro-imaging (e.g. CT, MRI). These studies provide an evaluation of anatomy but not function. Thus, while extremely helpful, they must be interpreted within the context of exam findings. Careful examination may make imaging unnecessary. Also, exam findings can make a strong case for the presence of a pathologic process, even if it is not seen on a particular radiological study (i.e. there are limits to what can be seen on even the most high tech imaging).
The above are not meant to lower expectations with regards to how well a physician should be expected to learn and perform the neurological examination. Rather, I mention these points to highlight some of the real and imagined obstacles to clinical performance. Like all other aspects of the physical exam, there is a wealth of information that can be obtained from the neurological examination, provided that it is done carefully and accurately.This is, of course, predicated on learning how to do it correctly. A few practical considerations/suggestions:
- In general, the neurological examination is not applied in its entirety to asymptomatic, otherwise healthy people as the yield (i.e. likelihood of identifying occult disease) would be quite low. It is, however, a good idea to practice the exam early in your careers, even when working with normal patients.This will improve the facility with which you perform the exam, provide you with a better sense of the range of normal, increase the accuracy of the results generated, and give you confidence in the meaning of findings identified when evaluating other patients.
- It is sometimes appropriate to perform only certain parts of the neurological examination (e.g. just cranial nerves; or only motor testing)These situations will become apparent with experience.
- The testing described below is still rather basic. There are many additional aspects of the exam that should be applied in specific settings. They are beyond the scope of this text, but can be found in other references.
- Take advantage of those opportunities when a more experienced clinician examines one of your patients. When possible, watch them perform their exam. Then go back alone and verify the findings.
Like any other aspect of the exam, the neurological assessment has limits. Testing of one system is often predicated on the normal function of other organ systems. If, for example, a patient is visually impaired, they may not be able to perform finger to nose testing, a part of the assessment of cerebellar function (see below). Or, a patients severe degenerative hip disease will prevent them from walking, making that aspect of the exam impossible to assess. The interpretation of findings must therefore take these things into account. Only in this way can you generate an accurate picture. Doing this, of course, takes practice and experience.
Adapted, with permission from University of California, San Diego School of Medicine By Charlie Goldberg, M.D.