Tremors are repetitive rhythmic movements that are involuntary and unintentional. They are back and forth movements commonly called oscillations.
An example is chattering teeth from cold temperatures or fear. It is not voluntary and it repetitive and rhythmic, back and forth. Most tremors occur in the hands and can be caused by many conditions. Tremors can be symptoms of neurological disorders such as Parkinson’s disease and multiple sclerosis. Brain damage from stroke or traumatic brain injury (TBI) can also cause tremors. Drug usage or withdrawal can sometimes elicit tremors. Hypoglycemia, vitamin deficiencies, and improper liver and thyroid functioning can also cause tremors.