Poder de Hinchamiento (PH)

The development study was carried out by a number of researchers. The author, in collaboration with these researchers, had a major contribution to the development study. The author was responsible for the collection of all data pertaining to the children's oral motor skills; this included administration of more than 90% of the assessments, rating from video and scoring of all 127 oral motor assessments. In addition, the responsibility for data entry and coordination of data analysis rested with the author. Data analysis was undertaken with the generous assistance of Dr Jim Stevenson, Miss Sally Baxendale and Professor David Skuse. In collaboration with colleagues, the Schedule for Oral Motor Assessment (SOMA) was developed.

Studv design

Three groups of children were studied.

• A comparison group consisting of children with normal growth trajectories and normally developing oral motor skills. These children were included to provide a standardisation sample.

• A group of children with non-organic failure to thrive (NOFT). The results of previous work (Skuse et al 1992, Mathisen et al 1989) suggested a substantial proportion of these children would have either immature or deviant oral motor skills.

subjects were selected because they had overt feeding difficulties associated with their neurological deficits.

Description of sample

The data were from a sample of 127 children which included 58 normally developing infants (the comparison group), 56 children with non-organic failure to thrive (NOFT) and 13 children with cerebral palsy (CP). The children ranged in age from 6 to 44 months. The mean age of the comparison group was 12.2 months (range: 8 - 2 1 . 2 months), the NOFT children 15 months (range: 8.75 - 19.5 months), and the children with cerebral palsy, 20.2 months (range 14.2 - 44 months).

Identification of subiects

The children in the NOFT and comparison groups was selected largely from an inner-city (population circa 140,000) whole population survey of 1558 full term singletons, born between 1st January and 31st December 1986, who were registered with participating child health clinics or family doctor practices. The growth of 2,510 infants who attended participating health clinics and group practices for weighing and developmental checks and who remained living in the district through the first year of life were monitored (Skuse et al 1992). Detailed information about the design of the prospective community study, such as sample selection and characteristics of the children, can be found in a variety of publications (Mathisen et al 1989, Skuse et al 1992, Skuse et al 1993, Skuse et al 1994).

N O F T infants:

The final sample of N O FT infants (n=56) was drawn from 2 studies. The first a pilot study investigating failure to thrive in infancy (Mathisen et al 1989) and the second, a community study of failure to thrive (Skuse et al 1992, Skuse et al 1993, Skuse et al 1994). Both the community and pilot study of failure to thrive, identified subjects whose growth faltered in the first 12 months of life. Subjects were selected according to strict criteria (Skuse et al 1992) which included:

• full term singleton births (> 38 weeks gestation)

• no severe intra-uterine growth retardation (birth weight above the 3rd population centile on charts standardised for gestation, sex, ordinal position, maternal height and mid-pregnancy weight (Tanner 1989). • weight for age at or below the 3rd population centile, this growth trajectory

having been sustained for at least 3 months (Tanner and Whitehouse 1984).

• prem ature and low birth weight babies were excluded because of the known association with below average postnatal growth (Brothwood et al 1987).

In the community study there were 1,554 infants whose birth weights were at or above 2,500 grams and whose gestation was 38 weeks or more. Fifty-two cases (3.3%) of failure to thrive were identified at 12-15 months of age. Only 3 cases were found to have a recognizable organic disorder accounting for their poor growth. Forty-nine cases of N O FT were diagnosed after full paediatric and

neurological logical examination. Full details are given in Skuse et al (1992). A further 9 cases of N O FT were included in the sample. These children were recruited during the pilot study (Mathisen et al 1989).

Comparison infants

The comparison group (n=47), was chosen from the population database, and matched to the 47 confirmed cases of N O FT on the basis of, sex, age, ethnic origin, birth weight (to within 300 grams), ordinal position and socioeconomic status. A further 11 comparison subjects were recruited during a pilot study for the same investigation (Mathisen et al 1989, Skuse et al 1992).

Children with cerebral palsy

Preschool children with a confirmed diagnosis of cerebral palsy and a significant degree of oral-motor dysfunction were identified from attenders at specialist clinics within the Greater London area. Paediatricians were contacted with a view to identifying a pilot sample under the age of 48 months. Thirteen children were referred and subsequently recruited. Inclusion criteria included:

• a confirmed diagnosis of cerebral palsy • aged less than 48 months

• the paediatrician nominated the child as having a significant degree of oral motor dysfunction

• the carers stated that the child had a major feeding problem.

feeding behaviour in preschool children with cerebral palsy (Reilly and Skuse 1992 in appendix 1).

Recruitment of subiects

The manner in which each of the samples was recruited is fully described in Reilly and Skuse (1992), Reilly et al (1995) and Skuse et al (1995) in appendix

1.

Procedure

The same procedure was adopted for each sample. Each family was visited at home and data were usually collected during one home visit, although occasionally two visits were necessary. Because the N O FT and comparison children were part of larger studies investigating different aspects of growth and development the families were visited by 2 other researchers and a number of instruments and interviews were administered. The visit concerned with feeding was usually the last home visit and comprised three parts;

• first, a semi-structured feeding interview with the child's primary caretaker, in most cases the child's mother.

• second, a video recording of the child's main meal of the day was made and

Instrument Design and development

The SOMA will be discussed in detail; other procedures have been described in earlier publications (Mathisen et al 1989, Mathisen et al 1992, Skuse et al 1992, Reilly and Skuse 1992) and are not relevant to this thesis.

Development

The development of the SOMA is described in Reilly et al (1995) in appendix 1. The following description will therefore concentrate on familiarising the reader with the instrument, the procedures for administration and the main components. The SOM A was developed to fulfil two purposes; first, to enable the objective recording of oral motor skills in infants between the ages of 8 and 24 months. Second, to use the assessment to evaluate oral motor function in children with either no overt neurological dysfunction or those with minor degrees of dysfunction. Because preexisting oral motor assessments had been developed primarily for use with individuals who had severe oral motor dysfunction resulting from neurological impairment, they were not applicable to the infants chosen in this study. As has already been highlighted no valid instrument with known reliability existed.

During the development phase it became clear that the SOMA should meet a number of basic requirements:

• First, it was essential that the child's oral motor skills should be challenged with a variety of textures. Although developmental trends in the normal process of oral motor skill acquisition following the introduction

of mixed feeding had been noted by various researchers, the process was not adequately described. Variation was noted in both the age at which the infant's first solids were introduced and when foods of increasing texture were offered to infants. Some infants will therefore have had a wide range of oral motor experiences with exposure to a variety of different tastes and textures while others may have had rather limited experience.

• Second, the manner in which the food and liquid were presented should be standardised. Recent evidence confirmed that oral motor performance varied according to the texture or implement used during feeding. Our own experience during pilot work showed that the way in which some mothers fed their children affected their oral motor performance. For example, they tended to tilt the spoon upwards when withdrawing it from the child's mouth, thus enabling the child to remove the food more easily. In addition, they often used the spoon to clean their children's lips of any remnants of food,This resulted in the rater being unable to observe either the child's ability to remove food from the spoon unaided or the combined action of the lips and teeth to clean the lips.

• Finally, the need for a standard set of feeding utensils was established. As a result of pilot work it became clear that the use of ordinary opaque plastic utensils was not ideal. It was often difficult to observe some oral motor behaviours and to ascertain if indeed the food had been removed

from the spoon or liquid taken from the cup. Accordingly, in conjunction with a manufacturer of infant feeding equipment (Cannon Babysafe), a standard set of feeding utensils was developed (spoons, bottles, cups and teats). The utensils were constructed of clear non-breakable plastic so that lip and tongue movements were clearly visible as was the amount of liquid in the bottle or cup. The design of the equipment resembled that commonly used by children in the 12-18 months age range. Examples of the equipment are shown in the photograph enclosed in appendix 2.

Administration

The SOMA was administered to each child approximately 1-2 hours after their main meal, in most cases lunch. The examination took on average 20 minutes. All SOM A procedures were video recorded using a JVC colour camera (Newvicon) which was either hand held, supported on a table or mounted on a tripod. Natural lighting was used. The camera was sensitive to low light conditions (15 lux), had a built in stop watch, a powerful zoom facility, automatic exposure control and automatic focusing. The assessment procedure was filmed by the mothers following a brief demonstration and practice session; they were positioned so that the view of the child's head and neck was taken from an oblique angle. The examiner was positioned in front of the child so that all food was presented in the midline. The assessment was administered according to strict criteria developed by the author and explained in full in the administration and scoring manuals (Reilly 1987 - unpublished data available from the author) (see appendix 3 and 4).

structure

The schedule is divided into four levels. The following schematic diagram (figure 1) from Reilly et al (1995) gives details of the structure of the SOMA.

Figure 1 : The four components of the SOMA are shown: the oral motor challenge categories (OMC), functional areas, functional units and the discrete oral motor behaviours (DOM). Oral motor challenge categories (OMC)y> Method of administration Choice Functional area Functional unit Discrete oral motor behaviours^

Figure 1. The four components of the SO M A

1 .Liquids 2.Puree 3. Semi­ solids

4. Solids 5. Cracker 6. Dried fruit 1.1 Bottle 1.2 Tralner- cup 1.3 Cup 1.4 Straw

Spoon Spoon Spoon Self-feeding

5.1 soft 5.2 medium 5.3 hard

Juice Yoghurt Peas Fruit salad Cracker Pear

Milk Mousse Cottage- Potato- Sesame Apple

Pu reed fruit cheese salad Oatcake Apricot

Miscellaneous

eg: graded jaw opening

eg: controlled sustained bite

Suck/Munçh/Chew

eg: rotary circular chewing movements

Oral motor challenge categories

Oral motor challenge categories (OM C) refer to the texture of the foodstuffs/liquids presented. They included;

Liquids