A person with involuntary head shaking could be suffering from a condition called essential tremor. Essential tremor is a condition that involves involuntary shaking of the head and the hands. This condition can worsen in some people if they are sitting or standing in a certain position.
The symptoms of essential tremor include shaky voice, head nodding, no tremors during sleep, tremors that worsen when a person is stressed and poor balance. This condition is usually confused with Parkinson's disease, which also has involuntary tremors when a person is not moving.
As of January 2015, the main cause of essential tremor is not known but it has been associated with abnormal brain activity that leads to tremor. The condition is also caused by genetics in nearly half of the people suffering from it, as stated by WebMD. A child who is conceived by a parent suffering from essential tremor has 50 percent risk of getting the condition, but the symptoms may fail to appear.
Diagnosis of the condition is based on the symptoms that a person is experiencing. There is no specific test for this condition. If the condition is mild, a person may not require treatment. Treatment using medications or undergoing surgery may be required if the condition is affecting the ability of a person to function.