Design and Content Validity of a New Instrument to Evaluate Motor Abilities of Children with Severe Multiple Disabilities: Movakic (Part-I)

Special Article - Pediatric Rehabilitation

Phys Med Rehabil Int. 2015; 2(9): 1068.

Design and Content Validity of a New Instrument to Evaluate Motor Abilities of Children with Severe Multiple Disabilities: Movakic (Part-I)

Mensch SM1,2,5*, Rameckers EAA3,4,5, Echteld MA1,6,7, Penning C¹ and Evenhuis HM¹

¹Intellectual Disability Medicine, Department of General Practice, Erasmus Medical Centre, The Netherlands

²Ipse de Bruggen, Centre of Expertise in Intellectual Disabilities, The Netherlands

³Department of Rehabilitation Medicine, School for Public Health and Primary care (CAPHRI), Maastricht University, The Netherlands

4Adelante Centre of Expertise in Rehabilitation and Audiology, The Netherlands

5University for Professionals for Paediatric Physical Therapy, AVANSplus, The Netherlands

6Stichting Wetenschap Balans, The Netherlands

7Prisma, Centre of Expertise in Intellectual Disabilities, The Netherlands

*Corresponding author: Sonja M Mensch, Erasmus Medical Centre, Intellectual Disability Medicine, Department of General Practice, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands

Received: October 16, 2015; Accepted: November 13, 2015; Published: November 20, 2015


Aim: Evaluation of motor abilities of children with severe multiple disabilities is often based on subjective assessment or on instruments validated for other target populations. A practical instrument for the evaluation of change in motor abilities is needed. In this study such an instrument is constructed and its content validity and applicability are tested.

Methods: The instruments content was developed using an expert focus group and a systematic literature review. Experts were consulted in all stages of development. Content validity was assesses using the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN). Applicability was assessed by experienced physical therapists in a pilot study among 53 children and adults with severe multiple disabilities.

Results: Movakic (MOtor eVAluation of KIds with multiple and Complex disabilities), a questionnaire consisting of 21 items on motor abilities, was constructed. Movakic scores are based on an assessment of motor performance of the child and have to be assessed by physical therapists. Movakic had adequate content validity and applicability.

Conclusions: Movakic’s good applicability and content validity suggest that is has potential to be a useful instrument in clinical practice. Movakic’s reliability is assessed in a prospective study, as reported in part II of this issue.

Keywords: Severe multiple disabilities; Motor abilities; Cerebral Palsy GMFCS V; Content validity; Evaluative instrument


SMD: Severe Multiple Disabilities; COSMIN: COnsensus-based Standards for the selection of health Measurement Instruments; Movakic: MOtor eVAluation of KIds with multiple and Complex disabilities; GMFCS: Gross Motor Function Classification System; CFCS; Communication Function Classification System; MACS: Manual Ability Classification System; IQ: Intelligent Quotient; ICF-CY: International Classification of Functioning, Disability and Health for Children and Youth; CLA: The Chailey Levels of Ability; BSID III: Bayley Scales of Infant and Toddler-Third Edition; PEDI: Pediatric Evaluation of Disability Inventory; GMFM-88: Gross Motor Function Measure (88 items); MHFMS: Modified Hammersmith Function Motor Scale; LE 85: Lower Extremity physical functioning and mobility skills; MFM: Motor Function Measure scale; TDMMT: Top Down Motor Milestone Test; VAB: Vulpe Assessment Battery; WeeFim: Functional Independence Measure for Children.


Children with severe multiple disabilities (SMD) are characterized by a severe or profound intellectual disability and severe motor impairments. There is no universal description of this group to be found in the current literature. Apart from “severe multiple disabilities”, which we selected, the terms “severe generalized cerebral palsy”, “profound and intellectual multiple disability”, “severe motor and intellectual disability”, “severe neurological impairment and intellectual disability” are used. Support for these children in acquiring or improving motor abilities is highly relevant for participation in general care situations and a sense of self-determination or autonomy. Availability of practical and reliable instruments for the measurement of motor abilities in these children is very important. However, instruments specifically designed for the measurement of motor abilities in this target group are lacking.

Children with SMD mostly have a level of motor abilities that is comparable to level IV/V of the Gross Motor Function Classification System (GMFCS) for children with cerebral palsy [1,2]: they typically are wheelchair-bound and only a few are able to move by crawling or using a physical aid [3,4,5]. They are usually severely limited in maintaining their body position or in transfers to another position. Communicative functions are highly limited; the children are only able to communicate non-verbally or through body language, which translates to Communication Function Classification System (CFCS) level V [6]. The child handles objects with difficulty or has severely limited ability to perform even simple actions. It requires support in almost all situations, which corresponds to Manual Ability Classification System (MACS) levels III-IV [7]. In addition, children with SMD are often diagnosed with sensory impairments, dysphagia often leading to respiratory infections [8], gastro-oesophageal reflux disease, epilepsy, scoliosis and contractures [9,10,11]. As a result, these children are fully dependent on their caregivers and material in their immediate vicinity for all activities of daily life.

In clinical practice, evaluation of motor abilities in children with SMD is often based on subjective assessments or on instruments developed for other target groups with motor disabilities. An instrument for this specific group, with the aim of longitudinal evaluation of progression, stabilization, or deterioration of motor abilities, which could then be applied in clinical physical therapeutic practice, was needed.

A systematic review of available instruments on motor abilities in children with severe disabilities [3], showed that eight instruments might be potential candidates for application in children with SMD. One instrument (TDMMT) was developed specifically for this population [12]. The seven other instruments were developed for children with cerebral palsy, other neurologic conditions, or motor disabilities in general. Although evaluation of psychometric properties of all eight instruments appeared incomplete, one or more of them might be suitable for children with SMD after some adaptation. Therefore, an expert focus group formulated suitability criteria and systematically judged the clinical suitability of the identified instruments for this group. The expert focus group determined the clinical suitability of the eight instruments based on five established criteria; 1) Low level of motor abilities, children with SMD are classified in level V (GMFCS) and can at best crawl. 2) Grading of scoring because of the subtle changes in motor abilities. 3) Manual and/or device support is a functional element in using motor abilities. 4) Non-verbal instruction, children with SMD have an Intelligent Quotient (IQ) <25 and do not understand verbal instruction. 5) Capability versus capacity and performance, which means the possibility, and not quality, of performing a motor ability is important. The suitability criteria were further specified in appendix A. As a result of the judgment, consensus was reached for all instruments; none of the selected instruments was found to be completely suitable in the target group. Therefore the focus group decided that development of a new instrument was needed. The procedure of the judgment is described in appendix A.

In this study we present the development of an instrument to evaluate motor abilities of children with severe multiple disabilities. The formulated suitability criteria were the starting point of the construction of the new instrument. We tested its applicability and content validity. In a companion publication in the current issue of this journal the reliability of the new instrument will be presented.


Expert focus group

The joint development and application of new suitability criteria and growing insights into wishes for an ideal instrument for children with SMD led to a strong motivation of the expert focus group to proceed and design a new instrument. Members of the focus group were selected from therapists of the Ipse de Bruggen Care Organisation with ten years or more experience with the target population. The expert focus group consisted of six well-trained physical therapists and an occupational therapist, each with over 15 years [range 15-30 years] of specialist experience in working with children with SMD. They were trained in the use of different instruments such as the Gross Motor Function Measure (GMFM), the Bayley Scales of Infant and Toddler-Third Edition (BSID-III) and the Pediatric Evaluation of Disability Inventory (PEDI). In addition, all have specific specializations in the field of intellectual disability and physical therapy interventions.

Theoretical framework

The content of the instrument was based on the next theoretical starting points: the International Classification of Functioning, Disability and Health for Children and Youth (ICF-CY) [13], multidisciplinary treatment goals and monodisciplinary treatment goals. Using the ICF-CY we can distinguish the levels of ‘body function and structure’, ‘activities’, and ‘participation’. Multidisciplinary treatment goals for children with disabilities are usually defined at the participation level of the ICF-CY, where as mono disciplinary treatment goals may concern the level of activities. In physical therapy, motor abilities (level of activity) are the primary focus for treatment, among other goals such as contracture management (level of body function and structure). This new instrument had the aim to evaluate motor abilities on the level of activities, and the users of the instrument had to be physical therapists working with children with SMD. Logically, the theoretical framework of the new instrument had to comply with the established criteria for clinical suitability.

Content validity

In the development of the new instrument, we used the general requirements (Table 1) on content validity of the COnsensus-based Standards for the selection of health Measurement INstruments (COSMIN). Assessing content validity is an important step in developing an instrument that aims to be relevant and comprehensive. An appropriate method might be to let experts judge the relevance and comprehensiveness of the items. The focus and detail of the items of the instrument need to be specifically designed to match the target population [14]. Since the COSMIN criteria are designed to assess content validity of an instrument in a certain study, only the first four criteria needed to be met to deem the items suitable for obtained adequate content validity.