Erratum to: Testing the potential of a virtual reality neurorehabilitation system during performance of observation, imagery and imitation of motor actions recorded by wireless functional near-infrared spectroscopy (fNIRS)

Correction

Following publication of our article [1], we realised that some of the statistical tests used were not appropriate. We have now conducted the appropriate statistical tests, and updated the relevant tables, figures five and six (Figures 1 and 2 here, respectively) and conclusions accordingly.

Figure 1

Unilateral group recorded over contralateral hemisphere: shown are the Δ[O ₂ Hb] amplitude changes with standard error of the mean (SEM) and statistical significances of repeated measures ANOVA.

Figure 2

Bilateral group recorded over contra- (dark gray) and ipsilateral (light gray) hemisphere: shown are the Δ[O ₂ Hb] amplitude changes with standard error of the mean (SEM) and statistical significances of repeated measures ANOVA.

For both the unilateral and the bilateral groups, analyses were recalculated.

Intra-condition differences:

• original publication [1]: paired t-test using means per trial for unilateral and bilateral group

• update: one-way repeated measures ANOVA using means per subject for unilateral and bilateral group

Inter-condition differences:

• original publication [1]: one-way ANOVA using means per trial for unilateral and bilateral group

• update: one-way repeated measures ANOVA using means per subject for unilateral and bilateral group

Conclusions

For the unilateral group (Table 1 and Figure 1), no changes in significance levels were found in Δ[O₂Hb] signals. For the bilateral group (Table 2 and Figure 2), the main differences compared to the original publication are that the intra-condition differences ([O₂Hb]_rest versus [O₂Hb]_stim) for the two conditions ‘Observation Right’ (O_R, p = 0.077) and ‘Observation Left’ (O_L, p = 0.080) recorded over the ipsilateral hemisphere do not reach significant level any more. Hence, the paragraphs discussing the intra-condition significances in those two conditions (sections Observation, imagery and imitation and Bilateral oxygenation of the Discussion) are only applicable for the contralateral hemisphere. Further, in both groups changes in significance levels were found for Δ[HHb]. However, since the Discussion and Conclusion of the originally published article only focuses on the concentration changes found in Δ[O₂Hb], this aspect does not change these sections.

Table 1 Unilateral group

Table 2 Bilateral group