Essential tremor-Parkinson's disease: A double whammy.
BACKGROUND
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.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Division of Movement Disorders, Department of Neurology, Yale School of Medicine, Yale University, New Haven, CT, USA; Department of Chronic Disease Epidemiology, Yale School of Public Health, Yale University, New Haven, CT, USA; Center for Neuroepidemiology and Clinical Neurological Research, Yale School of Medicine, Yale University, New Haven, CT, USA. Electronic address: elan.louis@yale.edu.
Elan D
ED
Louis
Department of Neurology, College of Physicians and Surgeons, Columbia University, New York, NY, USA.
Adina
A
Wise
Program in Physical Therapy, Department of Rehabilitation & Regenerative Medicine, College of Physicians and Surgeons, Columbia University, New York, NY, USA.
Roy N
RN
Alcalay
Program in Physical Therapy, Department of Rehabilitation & Regenerative Medicine, College of Physicians and Surgeons, Columbia University, New York, NY, USA; G.H. Sergievsky Center, College of Physicians and Surgeons, Columbia University, New York, NY, USA.
Ashwini K
AK
Rao
Department of Epidemiology, Mailman School of Public Health, Columbia University, New York, NY, USA.
Pam
P
Factor-Litvak
D000339:Affect; D000368:Aged; D017281:Cost of Illness; D020329:Essential Tremor / Q000150:complications* / Q000188:drug therapy / Q000453:epidemiology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008609:Mental Status Schedule; D010300:Parkinson Disease / Q000150:complications* / Q000188:drug therapy / Q000453:epidemiology / Q000503:physiopathology*; D004856:Postural Balance; D011446:Prospective Studies; D012720:Severity of Illness Index
Clinical; Essential tremor; Parkinson’s disease