The spasticity-related quality of life tool (SQoL-6D)
The Spasticity-related Quality of Life instrument (SQOL-6D) was developed to fulfil the need for a health-related quality of life measure that would be sensitive to the disease burden and changes following focal treatment for ULS and that could in future be used in economic evaluation of treatments for ULS.
It was developed on the basis of previous research led by King’s College London over a decade or more, including extensive analysis of goals and other outcomes from several large international studies.
The initial draft was then further refined through consensus by members of the advisory board set up to develop the SQOL-6D.
Six main goal areas have now consistently emerged from several studies (2-4) evaluating treatment for ULS. These are:
1. Reduction of pain and discomfort
2. Control of spasms and other involuntary movements
3. Maintaining the range of upper limb movements
4. Passive function: ease of caring for the affected limb
5. Active function – using the affected limb in activities
6. Mobility/ balance.
The Upper Limb Spasticity Index (ULSI) incorporates the GASeous (GAS evaluation of upper limb spasticity) tool alongside a targeted set of standardised measures that are selected from a limited set to according to the individual’s priority goals for treatment.
The Focal Spasticity Index (FSI) was a progression of the ULSI developed to incorporate both arm and leg spasticity presentations and incorporates GASLegs (Goal Attainment Scale - Leg Spasticity) for goal setting in leg spasticity in addition to the GASeous. A set of standardised set of measures are again recorded related to the goal and area of intervention.
The SQOL-6D was designed to complement the ULSI and GASeous, by providing a systematic assessment of subjects’ experience on the main impacts of ULS, and specifically in relation to the individual’s priority goals for treatment.
Structure of the SQoL-6D
The six dimensions (items) of the SQoL-6D were designed to map on to the same six main goal areas identified from our previous research and so to capture the direct experience and concerns that were most relevant to subjects suffering from ULS.
· Each dimension is assessed using a five-level scale ranging from 0 to 4, with higher scores meaning worse condition (e.g. greater pain, greater difficulty with caring for the affected limb…).
· The Total SQOL-6D score is computed as a linear transformation of the mean of the six dimensions scores to have the Total score ranging from 0 to 100, with the direction of scoring inverted, so that a higher score indicates a better quality of life, in line with other instruments.
Although the SQOL-6D is designed around the common goal areas for treatment of ULS as described above, each individual patient would usually only have goals for treatment in one to two areas. While the whole SQoL-6D tool provides an overall picture of spasticity-related health status, when evaluating response to treatment only the dimensions relevant to the identified treatment goals are expected to change. As a responsive measure of spasticity-related quality of life, the SQoL is designed be applied clinical practice in a similarly targeted manner to the ULSI, recording those dimensions that relate to the chosen goal areas.
An initial psychometric evaluation has been undertaken in a national, multicentre, prospective, longitudinal study conducted at eight sites in the United Kingdom (UK) which demonstrates acceptable reliability, validity and responsiveness to clinical change of the SQOL-6D Total score (in preparation for publication). Further evaluation is now underway.
The Sqol-6D 4