@article{ref1,
title="Postural instability and gait are associated with severity and prognosis of Parkinson disease",
journal="Neurology",
year="2016",
author="van der Heeden, Jorine F. and Marinus, Johan and Martinez-Martin, Pablo and Rodríguez-Blázquez, Carmen and Geraedts, Victor J. and van Hilten, Jacobus J.",
volume="86",
number="24",
pages="2243-2250",
abstract="OBJECTIVE: Differences in disease progression in Parkinson disease (PD) have variously been attributed to 2 motor subtypes: tremor-dominant (TD) and postural instability and gait difficulty (PIGD)-dominant (PG). We evaluated the role of these phenotypic variants in severity and progression of nondopaminergic manifestations of PD and motor complications. <br><br>METHODS: Linear mixed models were applied to data from the Profiling Parkinson's disease (PROPARK) cohort (n = 396) to evaluate the effect of motor subtype on severity and progression of cognitive impairment (Scales for Outcomes in Parkinson's disease [SCOPA]-Cognition [SCOPA-COG]), depression (Hospital Anxiety and Depression Scale [HADS]), autonomic dysfunction (SCOPA-Autonomic [SCOPA-AUT]), excessive daytime sleepiness, psychotic symptoms (SCOPA-Psychiatric Complications [SCOPA-PC]), and motor complications. In first analyses, subtype as determined by the commonly used ratio of tremor over PIGD score was entered as a factor, whereas in second analyses separate tremor and PIGD scores were used. <br><br>RESULTS were verified in an independent cohort (Estudio Longitudinal de Pacientes con Enfermedad de Parkinson [ELEP]; n = 365). <br><br>RESULTS: The first analyses showed that PG subtype patients had worse SCOPA-COG, HADS, SCOPA-AUT, SCOPA-PC, and motor complications scores, and exhibited faster progression on the SCOPA-COG. The second analyses showed that only higher PIGD scores were associated with worse scores for these variables; tremor score was not associated with severity or progression of any symptom. Analyses in the independent cohort yielded similar results. <br><br>CONCLUSIONS: In contrast to PIGD, which consistently was associated with greater severity of nondopaminergic symptoms, there was no evidence of a benign effect of tremor. Our findings do not support the use of the TD subtype as a prognostic trait in PD. The results showed that severity of PIGD is a useful indicator of severity and prognosis in PD by itself.<br><br>© 2016 American Academy of Neurology.<p /> <p>Language: en</p>",
language="en",
issn="0028-3878",
doi="10.1212/WNL.0000000000002768",
url="http://dx.doi.org/10.1212/WNL.0000000000002768"
}