Procedures

4.1. Recruitment of subjects

Applications were submitted to ethics committees at Great Ormond Street Hospital for Children NHS Trust and local health authorities for approval to approach the families of children under the authorities’ care. Once approval had been received from the committees children were recruited to the study by their Consultant Paediatrician or the Communication Aids Clinic team. At the point of recruitment the aims of the research and the procedures involved were outlined briefly to the children’s mothers. Subsequently, contact was made with the mothers by the author, the research aims and procedures were

discussed further and a date to see the children was arranged. As travelling can be difficult and tiring for physically disabled children and their families, and because children involved in the study were scattered across a wide geographical area, data collection sessions were conducted in the child's playgroup, school or local child development centre. Some mothers and their children were seen at the Wolfson Centre, when they attended the Communication Aids Clinic. Appointments were arranged at the convenience of the families and local services.

4.2. Data collection

As many locations were used, the rooms in which the sessions were conducted varied in their size, contents and the degree to which they were affected by noise from activities in the rest of the building. However, the rooms were generally quiet, all were large enough for the video camera to be placed eight feet in fi*ont of the mother and her child, tables and chairs of suitable heights were provided, and attempts were made to make the rooms as light as possible and free fi*om distracting toys. If children had special seating this was used throughout the session. Children's AAC systems were placed on the table within view so that they could request their system directly. Systems mounted on wheelchairs were in their usual position.

Each session followed the same order of activities. The aims of the research were again outlined to the mothers and children and an information letter was given to the mothers to read prior to them giving written consent for themselves and their child to participate in the study. (See Appendix 6.) Once consent had been given mothers were asked not to interpret the children's communicative signals for the author during the Script Situation.

The reason given was that the author wanted to "see how the children communicate with people whom they are not familiar with and who may not be able to understand them as well as their parents".

At the beginning of the session children were assessed using the LIPS and then either the RDLS or the TROG. Whilst the children were involved in these assessments their mothers completed the CDI. Following these assessments the mothers and their children were videotaped playing in the Conversation Situation. Each pair was instructed to "play and talk as you usually do" and told "here are some things you may want to play with." The wordless book was placed to the left of the child and the opaque box containing toys to their right, just out of reach. The camera was switched to automatic focus and the author sat out of view to the side or behind the pair depending on the room available. After ten minutes the author said to the child, "Shall we play with some of my toys now?" and either exchanged places with the child's mother or sat at the free side of the child depending upon the child's motor function. The author then said to the child "When we're playing with my toys I might do some funny things. If I do something silly you will tell me won't you?", in order to give the child permission to take an initiating role in the subsequent conversation. Mothers were again asked to watch rather than join in the conversation, this time indirectly by the author saying to the child "these games are just for you and me, so Mum/Mummy's going to be very quiet". The children were then videotaped with the author who elicited communication functions using the Script Situation. The order of presentation of the two situations was always the same in order not to influence the mothers' communication with their children.

Children who did not achieve a standard score of -2.0 or above on the RDLS/TROG or an IQ of 70 or above on the LIPS were excluded from the study. They were however, videotaped in both the Conversation and the Script Situations as it was felt that their families had made a commitment to the study. In these instances the child’s results were discussed by the author with the referring agent who made a decision of whether to pass on the information to the child's parents. As the author was not involved in the child's care it was not considered appropriate for her to embark on discussions that involved issues raised by standardised tests.

4.3. Effects of videotaping conversation on interaction data

The video camera was switched on once the two assessments had been completed and interaction was filmed for eleven to twelve minutes for the Conversation Situation. Interaction from the first ten minutes was analysed, as the pilot study had indicated that within this period of time all of the target communicative functions could be produced by both the mothers and the children. This decision was taken in spite of the possibility that the mothers and children may have behaved differently at the start of the session and gradually relaxed into more usual patterns of interaction as they began to feel more at ease (eg. Harris, Brooks, Jones & Grant, 1986; Howlin et al, 1973).

At the beginning of the Conversation Situation the children and their mothers were given a large opaque box in which they were told were toys with which they could play. This hopefully aroused the interest of the children and may have presented them with the opportunity to ask their mothers to open the box, request information about the toys, request that the object be given to them, or attract their mothers attention to the toys, at

the beginning of the filmed interaction. It is possible that the patterns of behaviour observed in previous studies (eg. Harris, 1982; Light et al, 1985b), in which mothers initiate frequently and control conversation, would be also observed in the present study. If this were so, the children may not have had sufficient opportunity to initiate moves to request attention or objects once conversation was underway. Thus, the interaction between the mothers and their children was analysed from the point at which the they were presented with the play materials.

Attempts to minimise changes in interaction were made by placing the video camera at least eight feet away from the mothers and children, the camera being switched to automatic focus and the author (the only person in the room apart from the pair being filmed) sitting out of the line of vision of the pair, to the side or behind them. Whilst the pair were filmed the author busied herself with papers, so that the mothers and children were not watched whilst they were playing.