A diagnostic tool routinely used in psychology is the Rey-Osterreith Complex Figure:

The patient is timed while copying the figure.  The figure and copy are removed and the patient re-copies the figure from memory immediately and again after 30 minutes.  It’s a sensitive measure of visuospatial recall, visuospatial recognition, response bias, processing speed, and visuospatial constructional ability.

Although the test has existed in its current form since 1944, there has been no publication on its utility in PSP.  Now, an Italian research group at the University of Pisa led by Dr. Luca Tommasini gave the test to 30 people with PSP-Richardson syndrome, 30 with Parkinson’s disease and 30 healthy persons matched to the others on age, gender and educational attainment. 

It was previously known that people with Parkinson’s make errors on the test related to planning and impulsivity.  The new study found that in PSP, those errors are more severe than in Parkinson’s, with the added problems of disinhibited repetition of some elements and “vertical expansion” of the figure.  The latter could be related to the difficulty in moving the eyes vertically or to an underlying difficulty in accurately conceptualizing vertical space.  In my own experience with people with PSP, there is disproportionate difficulty attending to objects and events at the upper and lower extremes of the visual space even if the eyes were still able to move adequately in those directions.

These results could help distinguish PSP-RS from PD diagnostically.  We await results for the other disorders with which PSP can be confused such as multiple system atrophy-parkinsonism and corticobasal degeneration.  We also await results from very early-stages of the disease, when such a diagnostic test would be most useful, and from variant forms of PSP such as PSP-parkinsonism and PSP-progressive gait freezing, where cognitive abilities are not usually as impaired as in PSP-Richardson syndrome.