The Stewart-Holmes test is used to examine the function of the cerebellum. It is done by asking the patient to try to touch the face with his hand against our resistance. The patient's arm is flexed at the elbow, after which we release the resistance and observe the inhibition of movement. In cerebellar disorders, there is a delayed slowing of the movement of the limb against the face ipsilaterally, and therefore the doctor should protect the patient's face with the other hand and brake the limb in time. It is examined on both upper limbs. 
Stewart-Holmes test (video, neurology 1.LF UK) https://el.lf1.cuni.cz/neuronorma/default/video/video28.html 
- ROTH, Jan – FIALA, Ondřej – RŮŽIČKA, Evžen. Neurological exams - normal [online]. [cit. 2012-11-22]. <https://el.lf1.cuni.cz/neurologie>.