A Guide to Common Neurological Examinations
Testing sensory function: beginning to differentiate
Once the extent of motor function has been established, the neurologist will examine the sensory system. This is a significant step in differential diagnosis because other major neurodegenerative diseases such as motor neuron disease can be eliminated as possibilities. Sensory disturbances are not seen in motor neuron disease, for example, whereas they are common early signs of MS. They can appear on one side of the body, in both extremities or in just one extremity. The onset is not the same for everyone.
Two common early sensory signs of MS are loss of temperature sensation and of sense of vibration. Vibration sense may be tested using a tuning fork placed on the big toe. A normal response is to describe the feeling as 'buzzing' or 'like electricity'. Signs of abnormality in this test, such as no sensation of buzzing or a different sensation, may indicate lesions in the spinal cord.
The doctor will strike the tuning fork to get the greatest vibration and will place it on your big toe. He'll ask you to describe what you feel.
