Essential tremor-Parkinson's disease: A double whammy

• DOI: 10.1016/j.jns.2016.04.040
• Publication Date: 2016-04-30T20:53:29Z
• Authors: Elan D. Louis; Adina Wise; Roy N. Alcalay; Ashwini K. Rao; Pam Factor-Litvak
• Keywords: Male; Essential Tremor; Parkinson Disease; Severity of Illness Index; Affect; 03 medical and health sciences; 0302 clinical medicine; Cost of Illness; Humans; Female; Prospective Studies; Mental Status Schedule; Postural Balance; Aged

Surprisingly little has been written about the combined clinical entity, essential tremor-Parkinson's disease (ET-PD), which is the result of a double disease hit. We carefully quantified tremor burden using a wide range of measures (tremor severity, tremor-related disability, tremor-related quality of life) and furthermore, studied additional motor and non-motor features in ET-PD.In this prospective, clinical-epidemiological study, we performed a standardized, structured clinical evaluation of 27 ET-PD patients, comparing them to age-matched samples of 35 PD and 109 ET patients.The number of hours/day shaking was lowest in PD (median=3.0), intermediate in ET (median=10.0) and highest in ET-PD (median=14.0) (p<0.001). All measures of mobility and balance (Berg Balance test, Activities-specific Balance Confidence Scale, Timed Up and Go test) worsened across groups in a stepwise manner from ET to PD to ET-PD (p<0.05). Mini-mental state test scores worsened (p=0.002) and daytime sleepiness increased (p=0.002) across groups from ET to PD to ET-PD.The ET-PD patient seems to be more than just a PD patient with a little more kinetic tremor. Aside from a significantly greater tremor burden, ET-PD patients exhibited more cognitive and sleep problems and more mobility and balance problems than patients with isolated PD.