Definition: “Coordination disorders often result from malfunction of the cerebellum, the part of the brain that coordinates voluntary movements and controls balance”.18 Anything that damages the cerebellum can lead to loss of coordination (ataxia). However, many other disorders can also cause loss of coordination. Here we want to capture any reduction or loss of coordination that cannot be objectively scored under one of the other parameters. Dysdiadochokinesis means the inability to execute fast alternating movements. In the neurological examination it is tested by letting the patient rapidly alternate pronation and supination movements of his hands or tapping his foot on the floor as fast as possible. When this is poorly executed or impaired, this is called dysdiadochokinesis, and is a sign of loss of coordination. Dysdiadochokinesis can be present in cerebellar, pyramidal, and extrapyramidal disorders. In the neurological examination, coordination testing is often referred to as cerebellar testing, but this is a misnomer. Although the cerebellum is very important in the production of coordinated movements and particular abnormal findings on coordination testing may suggest cerebellar disease, other systems also play critical roles. As an example, severe arm weakness will prevent a patient from performing finger-to-nose testing even though the cerebellum and its pathways may be intact.10 Finger-tapping, Rapid alternating movements, Finger-to-nose testing and heel-to-shin testing are all parts of the neurological examination to test the coordination. In the clinical summaries of the NBB, these findings are only occasionally reported. Therefore, we decided to leave them out of the scoring.