Dysdiadochokinesia · What Is It, Causes, Diagnosis, Treatment, and More

DDK often results from cerebellar dysfunction. The cerebellum is the part of the brain responsible for coordinated muscle movement, balance, gait (i.e., walking), and complex tasks. When an underlying problem affects the cerebellum, a person may have difficulty with coordination (i.e., cerebellar ataxia) speech, stability, and limb control.  

Cerebellar dysfunction can either be acquired or genetic. Examples of acquired causes include metabolic etiologies (e.g., Hashimoto disease or celiac disease), vascular etiologies (e.g., intracranial hemorrhage or stroke), brain cancer, infections (e.g., Lyme disease), inflammatory diseases (e.g., multiple sclerosis), or psychiatric problems (e.g., schizophrenia). Certain medications such as barbiturates and sedatives, as well as toxins from recreational drugs, alcohol, and botulinum can also lead to DDK. Finally, deficiencies in vitamins B, E, and thiamine can also increase the risk of developing cerebellar dysfunction. 

Examples of genetic or hereditary causes of DDK include Friedreich ataxia, spinocerebellar muscle atrophy, and Huntington disease.  

Diagnosis of DDK typically requires a physical examination to assess motor control and cerebellar function. A common method to test rapid alternating movement involves the individual starting with the palm of one hand resting on a flat surface. They are then asked to flip their hand repeatedly, alternating between having the palm face down and then face up.  

While assessing for DDK, other exams can also be done to test general cerebellar function including the Romberg test which requires the individual to stand with their heels together and eyes closed. If the individual has trouble balancing, it may indicate cerebellar dysfunction. Finally, the Stewart Holmes rebound test requires the individual to push against resistance, which is then suddenly removed. The examiner will assess how well the individual can control their balance after the resistance is taken away. 

Typically, further testing is done to determine the underlying cause. After completing a thorough physical examination and medical history review, blood tests may be performed to detect potential vitamin deficiencies, toxins, autoimmune antibodies, lipids, or changes in hormone levels. A full blood cell count may also be performed to help assess possible underlying conditions. Imaging techniques, such as computerized tomography (CT) scans of the head or magnetic resonance imaging (MRI) of the brain, may also be required to determine the source of cerebellar dysfunction. Finally, if genetic disorders are suspected, providers may recommend genetic testing.