Coordination of upper limb movements is assessed by the subject alternately touching your finger and their own nose. Move your finger from side to side, and then leave it in position and ask the patient to repeat the movement with their eyes closed (figure 8a–c). Ask the patient to draw imaginary circles in space or screw up imaginary jam jars (8d).
Fine movement can be assessed by tapping the dorsum of one hand with the other, and then alternately with the front and back of this hand (figure 8e,f). A more practical approach is to ask the patient to undo a button and write with a pen; various types of grip are further considered in the musculoskeletal system (page 131).
In the lower limb, place each heel in turn on the shin of the contralateral limb, and move it from the knee to the ankle and back. Ask the patient to touch your strategically placed finger with the great toe of each foot, then with their eyes closed; to describe circles with their great toe, or with their eyes closed, to ‘shoot’ the great toe with two fingers, after you have passively moved the foot (figure 9a–d).
Observe the patient walking (figure 10a); disturbances of gait can be accentuated by asking the subject to walk a straight line and repeat this heel toe fashion (figure 10b). Ataxia (incoordination of gait) may be due to an altered state of consciousness (e.g. excess alcohol, head injury, upper motor neurone spasticity), altered tone of cerebellar or basal ganglia disease and abnormalities of sensory input, when the patient is unaware of their position in space. Apraxia is failure to organise movements that are otherwise intact, and is associated with frontal lobe lesions.
Standing on toes and heels, and walking backwards on the heels, are further tests of coordination (figure 10c-e), but also depend on position sense, muscle power and normal joints. The altered coordination in cerebellar disease is characteristically slow, awkward and incomplete. It requires a few tries to complete a movement and it is often broken down into its component parts (disdiadochokinesis). Abnormalities of posture may be accentuated by asking the patient to stand still, with their feet together and their eyes closed (Romberg’s sign – figure 11).