Table 3. Test comparisons between controls and patients at baseline.

	UPDRS	PSPRS	PSPRS stage	Brixton	FAB	Hayling A	Hayling B	ACE-R	VOSP	Mu	Sigma
Control Mean	1	1.3	0	4.7	16.9	1.0	2.2	93.4	10.0	4.7	1.0
Patient Mean	33.8	45.0	3.3	3.1	10.8	3.0	2.3	76.4	7.6	4.0	1.3
t(df)	-9.7 (21.4)	-10.2 (20.2)	-13.7 (20.0)	2.3 (40)	6.8 (22.9)	-3.0 (35.7)	-0.12 (43)	7.1 (26.8)	3.6 (22)	2.1 (39)	-2.5 (24.3)
P value	<0.001	<0.001	<0.001	0.02	<0.001	0.005	1.0	<0.001	0.002	0.04	0.02

Mean control and patient baseline scores are given. UPDRS is the unified Parkinson’s disease rating scale, PSPRS is the PSP rating scale, FAB is the frontal assessment battery, ACE-R is the Addenbrooke’s Cognitive Examination revised, VOSP refers to the cubes subsection of the Visual Object and Space Perception battery, mu is the mean of the reciprocals of the median latency as measured by saccadometry and sigma is the mean of the variance of the saccade latencies. Hayling A refers to the number of category A errors in the Hayling test, and Hayling B to the number of category B errors. The scores for UPDRS, PSPRS, Hayling A and Hayling B are given untransformed, therefore a higher score indicates deteriorating function. t is the t statistic, df is the degrees of freedom, p values given are two tailed. Results have been corrected where control and patient variance were not equal. This process gives an altered value for degrees of freedom. Using Bonferroni correction with 10 comparisons, a p value less than p=0.005 would be significant. In that case mu, sigma, Hayling B and Brixton tests would not be significant.