title: The patient's perspective: The effect of levodopa on Parkinson symptoms.
abstract: Dopaminergic medication adjustments in Parkinson's disease are often solely based on patient reports. However, it is unclear how well patient-based ratings of the levodopa response correlate with clinician-based ratings, and whether this correlation differs between motor symptoms. Here we compare patient-clinician agreement for the effect of levodopa on resting tremor and bradykinesia/rigidity. Furthermore, given patients' reports that tremor is most troublesome during stress, we test for differences in patient-clinician agreement between tremor at rest and stress-induced tremor.
  
  
  
  We included 42 tremulous Parkinson patients, who were clinically rated (using the MDS-UPDRS) in a practically defined OFF-state and after levodopa-benserazide 200/50 mg. Using accelerometry, we quantified the effect of dopaminergic medication and behavioral context (rest vs. cognitive stress) on tremor intensity. Patients rated medication effects on tremor and bradykinesia/rigidity using visual analogue scales.
  
  
  
  There was only moderate patient-clinician agreement for the effect of levodopa on bradykinesia/rigidity (R2= 0.18; p < 0.01), and a tendency towards larger agreement for tremor (R2= 0.44; p < 0.001; difference between correlation coefficients: z = 1.64; p = 0.051). Patient ratings of tremor changes correlated significantly better with accelerometry for tremor during cognitive stress (R2= 0.35; p < 0.001) vs. tremor at rest (R2= 0.12; p < 0.05; difference: z = -2.35, p < 0.01).
  
  
  
  The moderate correlations between patient ratings and clinical/accelerometry changes indicate the need for methods to better monitor symptom severity and impairments in daily life, for example wearable sensors. Our findings also suggest that context matters: Parkinson patients' subjective experience of levodopa effectiveness on tremor was largely based on the ability of levodopa to reduce tremor during cognitive stress.
authors.affiliation: Radboud University Medical Centre, Donders Institute for Brain, Cognition and Behaviour, Department of Neurology, Nijmegen, The Netherlands; Department of Neurology, Medical University of Vienna, Vienna, Austria. Electronic address: heidemarie.zach@meduniwien.ac.at.
authors.forename: Heidemarie
authors.initials: H
authors.lastname: Zach
authors.affiliation: Radboud University Medical Centre, Donders Institute for Brain, Cognition and Behaviour, Department of Neurology, Nijmegen, The Netherlands.
authors.forename: Michiel
authors.initials: M
authors.lastname: Dirkx
authors.affiliation: Radboud University Medical Centre, Donders Institute for Brain, Cognition and Behaviour, Department of Neurology, Nijmegen, The Netherlands.
authors.forename: Jaco W
authors.initials: JW
authors.lastname: Pasman
authors.affiliation: Radboud University Medical Centre, Donders Institute for Brain, Cognition and Behaviour, Department of Neurology, Nijmegen, The Netherlands.
authors.forename: Bastiaan R
authors.initials: BR
authors.lastname: Bloem
authors.affiliation: Radboud University Medical Centre, Donders Institute for Brain, Cognition and Behaviour, Department of Neurology, Nijmegen, The Netherlands.
authors.forename: Rick C
authors.initials: RC
authors.lastname: Helmich
mesh_terms: D061725:Accelerometry / Q000379:methods; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000978:Antiparkinson Agents / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000188:drug therapy* / Q000503:physiopathology / Q000523:psychology*; D017060:Patient Satisfaction; D010817:Physician-Patient Relations; D016896:Treatment Outcome; D014202:Tremor / Q000188:drug therapy / Q000503:physiopathology / Q000523:psychology
chemical_list: D000978:Antiparkinson Agents; D007980:Levodopa
keywords: Cognitive co-activation; Levodopa-effect; Parkinson's disease; Tremor; Visual analogue scale