1. PLEASE NOTE: The very long list of references supporting this review has meant that only the most important are listed here and are represented by bold type throughout the text. The full list of references is available on the journal website http://www.ageing.oxfordjournals.org/ as Appendix 2.
2. Shannon KM . Movement disorders. In: Bradley WG, Daroff RB, Fenichel GM, Jankovic J, eds. Neurology in Clinical Practice, 4th edn, Vol. II. Philadelphia: Butterworth Heinemann, 2004; pp. 2144–5.
3. Elble RJ . Diagnostic criteria for essential tremor and differential diagnosis. Neurology 2000; 54 (11 Suppl 4): S2–6.
4. Benito-Leon J , Bermejo-Pareja F, Louis ED. Neurological Disorders in Central Spain (NEDICES) Study Group. Incidence of essential tremor in three elderly populations of central Spain. Neurology 2005; 64: 1721–5.
5. Louis ED , Marder K, Cote L et al. Differences in the prevalence of essential tremor among elderly African Americans, whites, and Hispanics in northern Manhattan, NY. Arch Neurol 1995; 52: 1201–5.