El Origen Del Lenguaje

Control analyses for randomisation

The possible effect of lack of proper randomisation of the task blocks was examined, by performing a two 2 (Order: ‘self-pleasant left’ condition vs. ‘any other left’ condition) x 4 (Left arm conditions: 1st Left block vs. 2nd Left block vs. 3rd Left block vs. 4th Left block): (1) Ownership; and (2) Motor Awareness update scores.

Ownership scores

A Mann-Whitney test found no main effect of Order (Z = -0.039, p = 0.969) and a Friedman test found no main effect of Left arm conditions (χ2₍₃₎ = 2.347, p = 0.504) was found. The lack of main effects suggests that im- proper randomisation of bocks during the task did not have an effect on Ownership data.

Motor Awareness scores

A Mann-Whitney U test found no main effect of Order (Z = -0.577, p = 0.564). A Friedman test found no main effect of Left arm conditions (χ2(3) = 2.717, p = 0.437). The lack of main effects suggests that improper randomi- sation of bocks during the task did not have an effect on Motor Awareness data.

Control analyses on baseline scores

Pre-touch Ownership and Motor Awareness scores of each patient’s first left-arm block were compared between AHP and HP groups, to examine if the groups differed significantly at the beginning of the task.

Ownership scores

A Mann-Whitney U test found no significant difference (Z = -0.203, p = 0.839) between AHP and HP groups.

Motor Awareness scores

A Mann-Whitney U test found a significant difference (Z = -3.188, p = 0.001) between groups, with the AHP group starting at a higher level (Mdn = 0.67) (i.e. answering more incorrectly) than the HP group (Mdn = 0).

Overall, the two analyses showed that patients in AHP and HP groups did not differ significantly in Ownership scores, showing comparable levels of DSO. However, the AHP group was found to be significantly more unaware than the HP group.

Self-touch enhancement effect analysis

Two 2 (Group) x 2 (Instructed Agency: ‘self’ vs. ‘other’) x 2 (Velocity: ‘pleasant’ vs. ‘neutral’) analyses were performed for the left and right arm, on Intensity of touch ratings, to examine whether self-touch was perceived as more intense than other-touch.

Left arm scores

A Wilcoxon signed rank test found a significant main effect of Instruct- ed Agency (Z = -4.052, p < .001), with ‘self’ touch being scored as more in- tense (Mdn = 3.87), compared to ‘other’ touch (Mdn = 2) (see Figure 3.1). No significant main effects were found for Group (Z = -1.125, p = 0.26), or, Ve- locity (Z = -1.125, p = 0.26). The interaction between Velocity and Instructed Agency was analysed by comparing the differential scores of each of the two variables. A Wilcoxon signed rank test found a significant interaction (Z = - 2.569, p = 0.01). Bonferroni-corrected (α = 0.025) post-hoc analyses showed that, in the neutral velocity, patients reported significantly more intense touch for ‘self’ (Mdn = 3.75) than for ‘other’ touch (Mdn = 2) (Z = -3.027, p = 0.002). Similarly, in the pleasant velocity, patients reported significantly higher inten- sity of touch for ‘self’ (Mdn = 4) than for ‘other’ touch (Mdn = 2) (Z = -2.851, p = 0.004). No significant interaction between Group and Instructed agency (Z = -1.024, p = 0.306), or Group and Velocity (Z = -0.113, p = 0.91) was found.

Figure 3.1: Means and standard errors of Intensity of touch scores for left arm: the Self-touch enhancement effect

Right arm scores

A main effect of Group was found (Z = -3.075, p = 0.002), with AHP having higher intensity scores (Mdn = 8.93), than HP (Mdn = 5.50). No signif- icant effect of Instructed agency (Z = -0.261, p = 0.794) was found. Also, no significant interaction was found between Group and Instructed agency (Z = - 0.094, p = 0.964).

Affective touch effect analysis

This was a 2 (Group: AHP vs. HP) x 2 (Instructed Agency: ‘self’ vs. ‘other’) x 2 (Velocity: ‘pleasant’ vs. ‘neutral’) design on Pleasantness of touch ratings, to examine if pleasant touch was indeed perceived as more pleas- ant.

A Mann-Whitney U test found a main effect of Group that approached statistical significance (Z = 1.947, p = 0.052), according to which the AHP group had the tendency to report higher pleasantness scores, compared to HP (Figure 3.2). No significant main effects of Velocity (Z = -0.601, p = 0.548), or Instructed agency (Z = -0.959, p = 0.338) were found. No signifi- cant interaction between Group and Velocity (Z = -0.086, p = 0.932), Group and Instructed agency (Z = -0.507, p = 0.612), or Velocity and Instructed

0 1 2 3 4 5 6 7 8 9 10

Pleasant Neutral Pleasant Neutral

Self Other Me an In te n si ty o f to u ch scores AHP HP

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agency (Z = -0.506, p = 0.613) was found. In addition, no significant interac- tion between Group, Velocity and Instructed agency was found (Z = -0.506, p = 0.617).

Figure 3.2: Means and standard errors of Pleasantness of touch scores for left arm

Main experimental analyses

This section investigated the effects of agency and velocity on Owner- ship and Motor Awareness, for left and right arms separately.

Left arm Ownership scores

A Mann-Whitney U test revealed a trend main effect of Group (Z = - 1.843, p = 0.065), indicating that the AHP group (Mdn = 0) had the tendency to improve more on Ownership, compared to the HP group (Mdn = 0). No main effects of Instructed agency (Z = -0.486, p = 0.627) and Velocity (Z = - 1.048, p = 0.295) were found. 0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0

Pleasant Neutral Pleasant Neutral

Self Other Me an Pl ea sa n tn es s o f to u ch s co re s AHP HP

The interaction between Group and Velocity was analysed by calculat- ing the differential score between ‘pleasant’ and ‘neutral’ scores, and com- paring it between groups. A Mann-Whitney U test found a significant interac- tion (Z = -2.098, p = 0.036). Subsequent Bonferroni-corrected (α = 0.025) pairwise comparisons found that in the AHP group, the pleasant velocity had the tendency to lead to more improvement in Ownership (Mdn = 0), com- pared to neutral velocity (Mdn = 0), although the result was not significant (Z = -1.708, p = 0.088). No significant result was found comparing pleasant and neutral velocities in HP group (Z = -0.935, p = 0.35) (see Figure 3.3).

Also, no significant interactions were found between Group and In- structed Agency (Z = -0.673, p = 0.501), or Velocity and Instructed agency (Z = -0.939, p = 0.348).

The interaction between Group, Velocity and Instructed agency was analysed by calculating the differential scores of Instructed agency and Ve- locity, and comparing the difference of these differential scores between groups. A Mann-Whitney U test revealed a significant interaction Z = -2.611, p = 0.009). Bonferroni-corrected (α = 0.025) post-hoc comparisons found no significant differences of the Velocity differential score between ‘self’ and ‘other’ conditions in the AHP group (Z = -0.870, p = 0.384). Similarly, no dif- ference was found in the Velocity differential score between ‘self’ and ‘other’ in the AHP group (Z = -1.192, p = 0.233).

Figure 3.3: Means and standard errors of Ownership updates (post – pre- touch) of AHP and HP in the different touch conditions

Left arm Motor Awareness scores

No significant main effects of Group (Z = -0.786, p = 0.432), Instructed Agency (Z = -0.888, p = 0.374) or Velocity (Z = -0.682, p = 0.495) were found. The interaction between Group and Velocity was investigated by cal- culating the differential score for ‘pleasant’ and ‘neutral’ scores and compar- ing them between groups. A Mann-Whitney test revealed a significant inter- action (Z = -1.966, p = 0.049) (Figure 3.4). Bonferroni-corrected (α = 0.025) post-hoc comparisons found no significant differences between AHP pleas- ant and HP pleasant (Z = -1.446, p = 0.148), or AHP neutral and HP neutral (Z = -0.296, p = 0.767) conditions. No significant interactions between Group and Instructed Agency (Z = -0.193, p = 0.847), and Instructed agency and Velocity (Z = -0.193, p = 0.847) were found. No interaction between Group, Velocity and Instructed agency was found (Z = -1.103, p = 0.27).

-0.20 -0.15 -0.10 -0.05 0.00 0.05 0.10 0.15 0.20

Pleasant Neutral Pleasant Neutral

Self Other Me an O w n er sh ip d iffe re n ce (p o st - p re ) AHP HP

Figure 3.4: Means and standard errors of Motor Awareness update scores (post – pre touch) of AHP and HP in the different touch conditions

Right arm Ownership scores

A non-significant trend main effect of Instructed agency (Z = -1.633, p = 0.102), or Group (Z = -0.059, p = 0.953) was found. Also, no significant in- teraction between Group and Instructed agency (Z = 0, p = 1).

Right arm Motor Awareness scores

No significant main effects of Group (Z = -1.121, p = 0.262), or In- structed agency (Z = -1.218, p = 0.223) were found. Also, no significant in- teraction between Group and Instructed agency was found (Z = -1.006, p = 0.314).

Control analyses on neglect

Two 2 (Group: AHP vs. HP) x 2 (Instructed agency: ‘self’ vs. ‘other’) analyses were performed, on extrapersonal and personal neglect self- reported scores, to ensure that any effects by self- and affective touch were

-0.20 -0.15 -0.10 -0.05 0.00 0.05 0.10 0.15 0.20

Pleasant Neutral Pleasant Neutral

Self Other Me an A w ar en es s d iffe re n ce (p o st - p re ) AHP HP

specific for Ownership and Motor Awareness, and not generally on the pa- tient’s awareness for their neurological condition.

Extrapersonal neglect

No significant main effects of Group (Z = -0.999, p = 0.318) or In- structed Agency (Z = -0.761, p = 0.446) were found. Also, no significant in- teraction between Group and Instructed Agency was found (Z = -4.75, p =0.659).

Personal neglect

No significant main effects of Group (Z = -0.33, p = 0.974), or Instruct- ed agency (Z = -0.33, p = 0.974) were found. Also, no significant interaction between Group and Instructed Agency was found (Z = -1.613, p = 0.107).

The lack of findings in the neglect conditions confirms that the velocity and agency of touch only affected Ownership and Motor Awareness, and did not have a more general effect, such as on awareness of drawing neglect.