Essential tremor (ET) is defined as a syndrome of tremor in posture and movement.1 It has also been discovered that cerebellar motor disturbances, cognitive disturbances, personality changes, hearing loss, and olfactory deficits are associated with ET.1 Symptoms are usually seen in the arms, head, or voice with occasional involvement of the legs, chin, and trunk.2 Essential tremor is often accompanied by a family history of similar tremors2,3 and has also been linked to several genes.4 The prevalence rate of ET is 3% to 6% of those older than 40 years.2 The upper extremity is affected most often, 90% to 95% of the time.3,5 The lower extremity is affected only 10% to 34% of the time. Essential tremor is thought to be due to a functional abnormality within the central nervous system. Clinically, it is a slowly progressive, monosymptomatic disorder with postural and kinetic tremors
It is hypothesized that ET is caused by a functional disturbance of the olivocerebellar circuit. Clinical evidence shows that ET disappears after lesions of the cerebellum, the pons, or the thalamus occur, which are all part of the cerebrocerebello-cerebral loop.4 Because there is no clear diagnostic test for ET, it must be defined in descriptive clinical terms, narrow or incomplete that may be.
Migraine is classified by the Headache Classification Committee of the International Headache Society as a headache that has additional components such as nausea, vomiting, photophobia, and phonophobia.6 The International Headache Society also reports women being affected by migraine 2 to 4 times more than men. Migraine affects the ability to perform activities of daily living as well as missed workdays.7 There are many theories as to the cause of migraine, including musculoskeletal and vascular disturbance. One theory defined by Moskowitz8 states the involvement of the trigeminovascular complex. An increase in discharge from the trigeminal nucleus from hormonal influences, environmental stressors, and low blood sugar could affect blood flow, causing a migraine with aura.