Background There is a growing interest in the cognitive impairment shown by patients with Huntington’s disease (HD). Alteration in visuospatial functions and saccadic eye movements had been demonstrated. Therefore, these factors should be taken into account when designing tasks to assess other cognitive domains. Stroop Colour and Word Test provide three scores based on the number of items completed on each stimulus sheet: colour naming (CN), word reading (WR) and interference (I). In Spanish population we have normative data for vertical form (items listed in columns).
Aims To compare the performance of the horizontal reading (items listed in rows) and the vertical reading (in columns) of the Stroop Test, and their correlation with the global cognitive status and eye movement disturbances in a sample of HD participants.
Method Pilot, cross-sectional study. The Stroop tests were administered to 2 pre-manifest HD and 4 manifest HD patients. The global cognitive status was assessed by the Mini-mental State Examination (maximum score 35). Eye movements were assessed by the UHDRS motor scale. Data were analysed using non parametric tests.
Results The total scores of WR, CN and I of the Stroop tests were similar when they were administered horizontally or vertically (p = 0.91; p = 0.17, p = 0.68, respectively). However, the vertical WR showed higher correlation with the MMSE (rs = 0.84) and inverse correlation with abnormal eye movements (rs = −0.94), compared to the horizontal WR (rs = 0.75, rs = −0.89, respectively).
Conclusions Vertical and horizontal forms of Stroop Test yield equivalent results in our sample. However, the vertical reading shows higher correlation with the cognitive status and with eye movement disturbances compared to the horizontal reading. Further studies including higher sample size and group differences (manifest vs. pre-manifest) are needed to confirm these preliminary results.
- word reading
- eye movements
- executive functioning