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Accuracy of clinical diagnosis in tremulous parkinsonian patients: a blinded video study
  1. Nin P S Bajaj1,2,
  2. Vamsi Gontu2,
  3. James Birchall3,
  4. James Patterson4,
  5. Donald G Grosset4,
  6. Andrew J Lees5
  1. 1Department of Clinical Neurology, Nottingham University Hospitals NHS Trust, Nottingham, UK
  2. 2Department of Clinical Neurology, Derby Hospitals NHS Foundation Trust, Derby, UK
  3. 3Department of Nuclear Medicine, Derby Hospitals NHS Foundation Trust, Derby, UK
  4. 4Institute of Neurological Sciences, Southern General Hospital, Glasgow, UK
  5. 5Queen Square Brain Bank for Neurological Disorders and Institute of Neurology, University College, London, UK
  1. Correspondence to Dr NPS Bajaj, Nottingham University Hospitals NHS Trust, D Floor West Block, Queen's Medical Centre, Nottingham NG7 2UH, UK; nin.bajaj{at}


Background This study examines the clinical accuracy of movement disorder specialists in distinguishing tremor dominant Parkinson's disease (TDPD) from other tremulous movement disorders by the use of standardised patient videos.

Patients and methods Two movement disorder specialists were asked to distinguish TDPD from patients with atypical tremor and dystonic tremor, who had no evidence of presynaptic dopaminergic deficit (subjects without evidence of dopaminergic deficit (SWEDDs)) according to 123I-N-ω-fluoro-propyl- 2β-carbomethoxy-3β-(4-iodophenyl) nortropane ([123I] FP-CIT) single photon emission computed tomography (SPECT), by ‘blinded’ video analysis in 38 patients. A diagnosis of parkinsonism was made if the step 1 criteria of the Queen Square Brain Bank criteria for Parkinson's disease were fulfilled. The reviewer diagnosis was compared with the working clinical diagnosis drawn from the medical history, SPECT scan result, long term follow-up and in some cases the known response to dopaminergic medications. This comparison allowed a calculation for false positive and false negative rate of diagnosis of PD.

Results High false positive (17.4-26.1%) and negative (6.7-20%) rates were found for the diagnosis of PD. The diagnostic distinction of TDPD from dystonic tremor was reduced by the presence of dystonic features in treated and untreated PD patients.

Conclusion Clinical distinction of TDPD from atypical tremor, monosymptomatic rest tremor and dystonic tremor can be difficult due to the presence of parkinsonian features in tremulous SWEDD patients. The diagnosis of bradykinesia was particularly challenging. This study highlights the difficulty of differentiation of some cases of SWEDD from PD.

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  • Funding NPSB was in part supported by an unrestricted investigator initiated grant from GE Healthcare UK.

  • Competing interests None.

  • Patient consent Obtained.

  • Ethics approval This study was conducted with the approval of the North Nottinghamshire ethics committee. ID: 07/Q2502/1.

  • Provenance and peer review Not commissioned; externally peer reviewed.