Music-based Autism Diagnostics (MUSAD) – A newly developed diagnostic measure for adults with intellectual developmental disabilities suspected of autism

Highlights

• A music-based framework is appropriate for assessing ASD in adults with IDD.

• The dimensional structure of the MUSAD is in line with the DSM-5 ASD criteria.

• The reliability estimates for all test scores were sufficient.

• Evidence for construct validity is provided.

Abstract

The MUSAD was developed as a diagnostic observational instrument in an interactional music framework. It is based on the ICD-10/DSM-5 criteria for autism spectrum disorder (ASD) and was designed to assess adults on a lower level of functioning, including individuals with severe language impairments. This study aimed to evaluate the psychometric properties of the newly developed instrument.

Methods

Calculations were based on a consecutive clinical sample of N = 76 adults with intellectual and developmental disabilities (IDD) suspected of ASD. Objectivity, test-retest reliability, and construct validity were calculated and a confirmatory factor analysis was applied to verify a reduced and optimized test version.

Results

The structural model showed a good fit, while internal consistency of the subscales was excellent (ω > .92). Item difficulties ranged between .04 ≤ p_i ≤ .82 and item-total correlation from .21 to .85. Objectivity was assessed by comparing the scorings of two external raters based on a subsample of n = 12; interrater agreement was .71 (ICC 2, 1). Reliability was calculated for four test repetitions: the average ICC (3, 1) was .69. Convergent ASD measures correlated significantly with the MUSAD, while the discriminant Modified Overt Aggression Scale (MOAS) showed no significant overlap.

Conclusion

Confirmation of factorial structure and acceptable psychometric properties suggest that the MUSAD is a promising new instrument for diagnosing ASD in adults with IDD.

Introduction

Autism Spectrum Disorder (ASD) is a frequently co-occurring condition in individuals with intellectual developmental disabilities (IDD). The prevalence of IDD within the autism spectrum is estimated to be between 30% and 35% (Centers for Disease Control and Prevention, 2012, Fombonne, 2003b). Despite the clinical relevance of this group due to high rates of comorbid challenging behaviors leading to an above-average administration of antipsychotics (McCarthy et al., 2010, Sappok et al., 2014a), and frequent admissions to inpatient treatment (Tsakanikos, Costello, Holt, Sturmey, & Bouras, 2007), research activities focusing on adults in the low-functioning range of the autism spectrum are rare (Matson & Shoemaker, 2009). There is a lack of diagnostic standards assessing ASD in adults with IDD, especially in those with limited language skills (Bölte and Poustka, 2005, Bölte and Poustka, 2005, Matson and Shoemaker, 2009). Generally ASD seems to be under-diagnosed in adulthood (Brugha et al., 2011): reasons for this may be the change of diagnostic criteria over the decades, increasing sensitivity to ASD in children or individual adaptation to social demands. In adults with IDD, diagnostics are further complicated by, for example, limited self-report and a lack of information about early child development due to loss of contact with families. Symptom overlap with schizophrenia, long-term hospitalization, severe sensory impairments, and IDD itself may lead to misinterpretation and wrong treatment concepts (Akande et al., 2004, Sappok et al., 2010). In cases of suspected ASD, comprehensive diagnostics is the basis for adequate treatment and support, enhancing health, reducing challenging behaviors, developing social and emotional skills and leading to a better quality of life.

In children and young people, a huge number of ASD screening tools and a diagnostic gold standard including a parental interview, the Autism Diagnostic Interview-Revised (ADI-R; Lord, Rutter, & Le Couteur, 1994) and a play- and interview-based behavior observational assessment, namely the Autism Diagnostic Observation Schedule (ADOS; Lord et al., 1989), allow for valid diagnostic statements in cases where ASD is suspected. While increasing numbers of specific tools and questionnaires have been developed to screen for ASD in adults with IDD in recent years, such as the Pervasive Developmental Disorder in Mental Retardation Scale (PDD-MRS; Kraijer & Bildt, 2005), the Autism Spectrum Disorders – Diagnosis for intellectually disabled Adults (ASD-DA; Matson, Wilkins, Boisjoli, & Smith, 2008), the Diagnostic Behavioral assessment for Autism Spectrum disorder – Revised (DIBAS-R; Sappok, Gaul, et al., 2014), and the Autism Check List (ACL; Sappok, Heinrich, & Diefenbacher, 2014), there is a lack of diagnostic standards and a specific measure for structured behavioral observation in adults with IDD and severe language impairment. Even though the ADOS is generally applicable in adults with IDD (Berument et al., 2005, Sappok et al., 2013b), childlike materials and prompts seem to be inappropriate in assessing adults. Additionally, limited feasibility is reported, correlating with the severity of IDD and speech impairments (Bergmann et al., 2015, Sappok et al., 2013b). In light of the lack of specific ASD diagnostic measures for adults on a lower level of functioning, valid procedures based on nonverbal communication are highly desirable.

Musical interaction as a nonverbal means of communication and an adult form of play may build a framework to assess ASD in adults with IDD (Wigram, 2000). The strong connection between music and ASD is described in terms of exceptional musical interests and abilities early on by Kanner (1943), and has been supported recently by a Cochrane review of music therapy in the treatment of children with ASD (Geretsegger, Elefant, Kim, & Gold, 2014). But what kind of diagnostic information might music provide? Interactional skills, social affect, and reciprocity are to be observed in joint music-making, including individuals with severe language impairments. Stereotyped, restricted, and repetitive behaviors and interests may occur in musical exploration and expression. Multisensory aspects of musical instruments (auditive, visual, haptic, olfactory) allow the investigation of abnormal sensory interests. Motor coordination and mannerisms are to be seen in the ways in which instruments are handled (right-left drum beat) and in movements like tapping and dancing. Overall, most behavioral characteristics listed as core symptoms of ASD in the ICD-10 and DSM-5 can be observed in musical action and interaction (Bergmann et al., 2015). Given the background of the strong association between music and ASD, several assessment tools and two explicit music-based diagnostic instruments have been developed in the field of ASD: Wigram's Harper House Music Therapy Assessment (1999) and the Music Therapy Diagnostic Assessment (MTDA; Oldfield, 2004). Both were developed to assess children and lack a comprehensive psychometric verification.

In 2009, the Music-based Scale for Autism Diagnostics (MUSAD) was designed in a music therapeutic setting alongside further specific instruments for ASD screening in this group of patients (Sappok et al., 2014b, Sappok et al., 2014c). The instrument was developed along the ICD-10 research criteria for autism (F84.0, F84.1) taking into account the latest changes made in the DSM-5 (Bergmann et al., 2015). The concept is comparable to the ADOS, using prompts to provoke diagnostic relevant behaviors that are to be coded on a 4-point Likert scale regarding the severity of symptom expression in the autistic spectrum. Ten predefined active musical interactional situations were used to create a playful, naturalistic, and age-appropriate framework, also engaging non-speakers in a diagnostic assessment. The implementation procedure is as follows: 1. Free play (warm-up); 2. Piano (joint attention); 3. Gongs (dynamic/affective attunement); 4. Congas (musical dialog); Break; 5. Sing a song (socio-emotional togetherness); 6. Ocean drum (contact via instrument, imagination); 7. Symbolic instruments (pretend play); 8. Music selection (asking for help); 9. Balloon game (turn-taking): and 10. Dancing together (bodily synchronization). The conga situation may provide an example of the entire diagnostic work-up:

• Implementation

  The Investigator initiates joint play with a common pulse, followed by slight tempo changes and again stabilization of a basic beat. The next task is to hit the drum with alternating right and left hand. Next are simple motifs and breaks in order to initiate interplay; if the client does not react or stops, he or she is supported verbally and gesturally. Finally a crescending drum roll with release of the suspense in a final blow invites the client to share affectivity.

• Description

  To change perspective, the investigator is first asked to describe the client's behaviors in free-text along predetermined observation priorities: i.e., in this case, motor coordination, imitation skills, metric synchronization and variations, turn-taking skills, social reciprocity and shared joy.

• Scoring

  Task-specific items like “Rhythmic synchronization of tempo changes” or overall items like “Joy in playing together” are to be scored on a 4-point scale in order to operationalize ASD-related behaviors. (For a complete description see: Bergmann et al., 2015).

Eighty-eight items are grouped in five domains according to ASD main characteristics, including (1) social interaction, (2) communication, (3) stereotyped and repetitive behaviors, (4) sensory-motor issues, and (5) affective dysregulation. Temper tantrums, aggression, and self-injury are mentioned as “nonspecific problems” in the ICD-10, so we added the last domain (affective dysregulation) as a possible ASD marker. Regarding the future development of diagnostic criteria and diagnostic understanding of ASD, motor issues were also included. The scale consists of two modules, one for verbal and one for non-verbal individuals. However, the two modules differ only in the domain of social communication (2), involving a set of verbal items or an alternative nonverbal item set without influence for conducting the investigation. The inclusion of low-level musical interventions without the requirement to imitate (Bergmann et al., 2011, Schumacher and Calvet, 2007) and a course of tasks with increasing demands on social and physical contact was developed in order to decrease irritability and rejection in individuals with a low level of functioning facing an unfamiliar environment. In a previous study, a feasibility of 95% was achieved when applying the MUSAD in adults with IDD (Bergmann et al., 2015), which is considerably higher than the feasibility for the ADOS in this group, which was reported at 81% (Berument et al., 2005, Sappok et al., 2013b).

The primary objective of the present study was to examine the MUSAD along the main criteria for test quality, i.e., objectivity, reliability, and validity based on a clinical sample. The secondary aim was the improvement of test economy by reducing the number of items.