This interesting research out of Germany looked at 12 cases of the RS (Richardson’s Syndrome) form of PSP, 5 cases of the PSP-P (PSP-Parkinsonism) form, 27 cases of Parkinson’s Disease, and 23 healthy controls. (It was just published on PubMed though the journal is dated Dec 2008 and the epub is dated 1/14/09.)
Cases of PSP-parkinsonism are characterized by asymmetric onset, tremor, and a moderate initial response to levodopa. Obviously, PSP-P cases are frequently confused with Parkinson’s Disease.
Because PSP-P and PD are so similar in symptoms, clinicians need a way to differentiate the two disorders. The German researchers conclude that video-oculography (VOG) can be used because of the “clear-cut separation between PSP-P and [PD] obtained by measuring saccade velocity.” Typically, a neuro-ophthalmologist has the equipment to conduct a VOG.
It should be noted that none of the patients had pathologically-confirmed diagnoses, so the results may change based upon that.
Robin
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Journal of Neurology. 2008 Dec;255(12):1916-1925. Epub 2009 Jan 14.
Differential diagnostic value of eye movement recording in PSP-parkinsonism, Richardson’s syndrome, and idiopathic Parkinson’s disease.
Pinkhardt EH, Jürgens R, Becker W, Valdarno F, Ludolph AC, Kassubek J.
Dept. of Neurology, University of Ulm, Ulm, Germany.
Vertical gaze palsy is a highly relevant clinical sign in parkinsonian syndromes. As the eponymous sign of progressive supranuclear palsy (PSP), it is one of the core features in the diagnosis of this disease.
Recent studies have suggested a further differentiation of PSP in Richardson’s syndrome (RS) and PSP-parkinsonism (PSPP).
The aim of this study was to search for oculomotor abnormalities in the PSP-P subset of a sample of PSP patients and to compare these findings with those of (i) RS patients, (ii) patients with idiopathic Parkinson’s disease (IPD), and (iii) a control group. Twelve cases of RS, 5 cases of PSP-P, and 27 cases of IPD were examined by use of video-oculography (VOG) and compared to 23 healthy normal controls.
Both groups of PSP patients (RS, PSP-P) had significantly slower saccades than either IPD patients or controls, whereas no differences in saccadic eye peak velocity were found between the two PSP groups or in the comparison of IPD with controls.
RS and PSP-P were also similar to each other with regard to smooth pursuit eye movements (SPEM), with both groups having significantly lower gain than controls (except for downward pursuit); however, SPEM gain exhibited no consistent difference between PSP and IPD.
A correlation between eye movement data and clinical data (Hoehn & Yahr scale or disease duration) could not be observed.
As PSP-P patients were still in an early stage of the disease when a differentiation from IPD is difficult on clinical grounds, the clear-cut separation between PSP-P and IPD obtained by measuring saccade velocity suggests that VOG could contribute to the early differentiation between these patient groups.
PubMed ID#: 19224319 (see pubmed.gov for this same abstract)