Discussion

Whilst the initial purpose of this second phase was to develop a set of TELER Indicator definitions that had both content and construct validity, a number of important issues emerged during the developmental process.

These can be listed for discussion as follows:

* Changes that occurred in the indicators to satisfy one of the theories of measurement.

* Changes that occurred in the indicators to satisfy the theoretical basis of the Bobath Approach.

* A pattern of change was recorded when the Indicators were used during the implementation of the Bobath Approach for stroke rehabilitation.

9.5.1 Satisfying Measurement Theory

In the initial literature review, the importance of measurement theory to physiotherapist seeking ways to evaluate practice was clearly identified (section 3.3). One of the criteria established in Phase I was that a measure must have logic, that is, it must fulfil the basic principles on which measuring scales are based. This TELER system was chosen specifically because it appeared to fulfil this requirement.

When developing the Function Indicators during Phase 11 it became apparent that neither clinical or expert knowledge was sufficiently comprehensive to enable the definitions of certain motor tasks if these were to be placed in a hierarchical order. An example of this dilemma arose in the original development of the Indicator o f'rolling see Figure 13b. Whilst clinicians had placed the components of rolling into a hierarchy there was some controversy about this and the indicator scores were frequently out of sequence if used in clinical practice.

When critiqued by the BBTA two issues were discussed, one relating to the task, and the other to the clinical steps involved in the task. It was agreed at the consensus meeting that whilst rolling was frequently referred to in treatment programmes, what was actually

required by patients was the more functional skill of 'turning over in bed\ the components of which were defined and placed in the component indicator structure. This then fulfilled the patients requirement more fully and placing the components into a component TELER Indicator (Le Roux, 1993, 1995a; Mawson, 1995b) ensured that one of the theories of measuring scale which states that, the codes of the ordinal scale must be in a hierarchical order (Stevens, 1956), could then be satisfied. Once used, a pattern of achievement might be recorded that, once explained, might lead to the development of more formal knowledge. Figure 7 shows the process by which informal knowledge is used in the development of TELER definitions and how, when measurement theory is satisfied, formal knowledge may emerge. The process presented in Figure 7 was undertaken during the present study enabling the development of a theoretical basis for stroke rehabilitation.

9.5.2 Fulfilling the Theoretical Basis of the Bobath Approach

During the validation process, it became apparent that the Indicators were evolving and changing in response to the conceptual basis of the approach being measured. The initial set of indicators were developed in response to patients’ needs, the definitions were the result of clinical experiences and were defined by physiotherapists working within the stroke services. When they moved on to the BBTA it was interesting to note, that whilst they were not changed in their fundamental structure, elements of the Indicators were changed to fulfil the needs of the approach. ( See Appendix 2.3.)

It can be seen that independent sitting was renamed ’Maintained Sif and the definition 0: was changed from 'unable' to ’unable to be placed. Whilst this may not appear to be a very significant change it does, in fact, reflect a fundamental concept of the approach, the importance of 'acceptance o f the base o f support\ This phrase frequently used in the literature (Shumway-Cook et a], 1988; Bromley, 1994; Bobath, 1990) and during the teaching process lacked a working definition. However, the development of the indicator had required the therapists to identify what was meant clinically by this term. It can be seen from the list of clinically significant steps that to be able to maintain sitting (accept base of support) required the patient to be able to take weight through the

supporting surfaces, align the shoulders over the pelvis and keep the hands resting equally on the knees. The theory underlying these steps related to the concept of normal equilibrium requiring normal tone to maintain the centre of mass over the supporting surface achieved by muscle activity around weight bearing joints. As Shumway-Cook suggests, this activity requires a combination of sensory and motor processes to be operational, the Bobath concept stating, that abnormal tone interrupts both processes, thereby interrupting the selective activity required to achieve normal equilibrium.

Similarly, the indicator of Lying and Stand became Maintained Lying and Maintained Stand. The results of this study would suggest that the indicators o f'Maintained Sit or Stand are prerequisites for the next stage of recovery. Without the ability to accept a midline position taking weight therefore symmetrically through that supporting surface and maintain equilibrium activity the patients would be unable to move away from or back to the original position, using the same muscle activity to achieve a new or changed base of support. The final list of indicators resulting from the BBTA consensus meeting included this concept of acceptance of base of support, and change the base of support, including the concept of maintenance prior to change. See Figure 13.

Obviously, the working hypothesis that an association exists between the recovery of movement skills required testing. The assumption that the ability to maintain a position against gravity was a prerequisite for the ability to with moving away from and back to that position, became one of the working hypothesis to be tested in Phase 111 of this study. This concept of prerequisite skills, conflicts with the assumption on which Carr and Shepherd have based their approach to the rehabilitation of stroke patients (Carr and Shepherd, 1987a). This will be discussed in the following chapter.

9.5.3 Operationalising Informal Knowledge

During the developmental process it became apparent that, when defining the clinically significant steps required to achieve the tasks or goals required, a model of recovery was being used that fulfilled the conceptual basis of the approach. As reviewed in the literature, the Bobath Approach had moved towards the rehabilitation of selective trunk activity, regarding trunk activity as central to all normal movements (Bobath, 1981; Davies, 1985, 1990). Mohr (1990) in a teaching document, clearly discusses the

importance of selective trunk activity identifying four muscle groups that include flexion, extension, side flexion elongation and axial rotation. She suggested, that these were hierarchical and that the base of support on which the functional activity occurred, dictated the complexity of the task.

The results of this phase would support the previously identified model (Mohr, 1990) confirming that selective activity in the trunk is essential to the achievement of the identified goals. The hierarchical recovery of this activity appears to be as follows:

FIGURE 11

Model of Selective Trunk Activity Incorporated within the TELER Indicator Definitions

* Flexion of the trunk with a posterior pelvic tilt * Extension of the trunk with an anterior pelvic tilt * Side flexion and elongation of the trunk

* Rotation of the trunk

Other selective activity in the hip, knees and ankles were also identified and there appeared to be a hierarchy within the activity defined. Other researchers have attempted to use aspects of trunk activity to develop a measure of outcome. (Parry, 1983; Carr et al, 1985; Ashbum, 1982). However, previous authors have not identified the individual items that enable ’Maintained S it or 'Dynamic Sit. This study has also identified the selective trunk activity required to achieve Maintained Stand and ’Dynamic stand.

In a recent publication, Nieuwboer et al., (1995) also suggested that selective trunk activity and symmetry are components of normal sitting, in their work on the measurement of sitting. However Nieuwboer first identified the abnormalities and problems produced by a stroke by interviewing three experienced neurophysiotherapists and observing five stroke patients. From this, they developed 28 items which ‘involved maintaining different positions against gravity and making postural adjustments during

This problem based approach resulted in a confusing list of scoring criteria that include abnormal movements and normal movements, plus the fact that trunk selectivity is limited to flexion and extension and lateral elongation with upper limb weight bearing. This combination of activities potentially limits the measurement of true selectivity of trunk activity. Charlton (1995), Gordon (1987) and Horak (1992) clearly suggest, the way forward in understanding motor control lies in the study of action or motor tasks. The development of the TELER Indicators involved the analysis of motor tasks, the resulting definitions of selective trunk activities being an identification of normal activity, not abnormal responses to a lack of selective activity, (Nieuwboer et al., 1995).

Nieuwboer et al., confirmed the validity of certain definitions of the developed TELER Indicators as she included as relevant the selective activities of flexion and extension in the trunk and elongation with side flexion when the patient lent towards the weight bearing arm. All of the physical functional indicators developed during this phase include these selective activities however they also include the ability to rotate the trunk back towards midline. Without this final element of selective activity, the ability to balance, walk, go up and down stairs or change postures in any way would be almost impossible as rotation around the vertical or horizontal axis occurs during most advanced movement skills.

The importance of this selective trunk activity during the recovery of movement following a stroke has received little attention in the research literature, even though it would appear to be the basis of all activities against gravity (Charlton, 1995). Shumway- Cook et al., (1988) suggest that normal balance or equilibrium which they define as: 'the ability to maintain the centre o f body mass over its base o f support with minimal

postural sway' is frequently lost following a stroke. Whilst this article is predominantly

about standing following a stroke, it can be assumed that this loss of the ability to maintain the centre of mass over the base of support occurs in a variety of other postures such as sitting.

It is interesting that, following the development of the final catalogue of TELER Indicators, the literature supports the conceptualisation of maintenance and changing base of support as a measurement of movement. The findings of this phase are further

supported by Shumway-Cook and Woollacott (1995) as they suggests that, whilst the control of posture and balance involve the integration of sensory and motor processes, it is achieved by the co-ordinated activity of trunk and leg muscles.

Shumway-Cook and Woollacott go on to cite a number of references to lower limb activity and decreased sensory information (Arcan, et al., 1977; Black et al., 1982), she fails however, to discuss or report any research relating to the activity in the trunk during movements, against or towards gravity. Although this study was about the recovery of standing following a stroke, trunk alignment was quantified in terms of lateral sway, this being the transfer of weight laterally using centre of pressure dated from a static force plate.

This data is totally lacking in clinical significance as stroke patients not only require to transfer weight on to the hemiplegic leg, but they also need to maintain alignment or equilibrium over this new base of support. Whilst Shumway-Cook correctly identified the importance of maintenance of equilibrium by trunk activity, she ignores this concept when trying to measure the rehabilitation of standing in stroke patients.

This is an extremely important area of stroke rehabilitation as it might.be suggested that the ability to transfer weight on to either leg whilst maintaining a new postural alignment is, a prerequisite for stepping prior to walking. This assumption will be tested during the third phase of this study, using the validated Physical Function Indicator of Dynamic

Stand and Stand-Step.

Having defined the selective activity of the trunk as items within the TELER Indicators, these could then be used to investigate the relationship between the recovery of trunk activity in different motor tasks. Of particular interest would be the association between the maintenance of a posture and movement from one posture or base of support to another. This might provide evidence of the link between hierarchical movements within the trunk and the size of the base of support, suggested by Mohr (1990 ) in her teaching document on the management of the trunk.

9.5.4 Validating the TELER Definitions: Kinematic Analysis

If the indicators developed during this phase were to be used to provide this evidence, the biomechanical literature must be reviewed to establish, whether the definitions provided by the clinicians in Phase 11 are supported by quantitative analysis of movement. Millington (1992) using kinematic analysis of ten elderly subjects, identified three phases of the movement of Sit to Stand. See Figure 14.

FIGURE 14

Three Phases of Sit to Stand Motion Defined from Kinematic Analysis

KNEE EXTENSION TRUNK _{TRUNK EXTENSION} FLEXION

2 7 3 6

PERCENT OF MOTION

100