A challenge for school-based speech-language pathologists is to meet their multiple responsibilities adequately while addressing the unique needs of students with autism spectrum disorders (ASD). This challenge requires that school-based SLPs maintain current knowledge on research and clinical practice recommendations for students with ASD.
In February 2007 the Centers for Disease Control and Prevention revised the prevalence figures for ASD to one in every 150 individuals. Once characterized as a "low-incidence disorder," ASD is now one of the highest-frequency programming challenges in the educational setting.
There are several hypotheses for the increased incidence. One contributing factor is an increased awareness of the disorder through the Internet, media coverage of high-profile cases, professional training, and parent support groups and services. A second factor is the ability to diagnose the full spectrum of autism disorders available since 1994, when the diagnostic criteria were modified in the Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition (American Psychiatric Association, 1994) to include Asperger's syndrome and higher-functioning individuals within ASD. A third factor appears to be an actual increase in the incidence and severity of childhood developmental disorders in general.
Screening and Assessment
SLPs are often on the front line for preschool screening and intervention. The unusual developmental characteristics associated with ASD are noticed immediately by SLPs evaluating language acquisition patterns and milestones. Guidelines for Speech-Language Pathologists in Diagnosis, Assessment, and Treatment of Autism Spectrum Disorders Across the Life Span (ASHA, 2006c) lists multiple assessment tools for professionals to use as part of a multidisciplinary team (see online sidebar for more information on ASHA documents).
As ASD has gained a higher profile nationally, disorder labels are being applied at younger ages to qualify for intervention services. Parents concerned about their child's development typically turn to their pediatrician. However, a study conducted by Dosreis (2006) found that very few pediatricians routinely screen for ASD and most are unfamiliar with screening tools. The pediatricians who reported screening for ASD admitted that the assessment was prompted by parent concerns rather than their own routine practice procedures. In response to escalating concerns, the American Academy of Pediatrics published Caring for Children with Autism Spectrum Disorders: A Resource Toolkit for Clinicians, a pediatric autism screening toolkit for health care professionals.
Professionals need to consider the possibility of other developmental disorders that mirror many of the ASD characteristics during the preschool years. There is considerable overlap of characteristics in the profiles of different developmental disorders during the preschool years. The focus should be on identifying developmental areas that have been compromised and need to be addressed in treatment goals.
It is important to realize that many of the assessment tools are designed for ASD. By choosing an autism screening checklist or assessment instrument, the professional may have already decided that a child's developmental behavior pattern indicates ASD. For example, a clinician's use of the Childhood Autism Rating Scale, Gilliam Autism Rating Scale, Autism Diagnostic Observation Schedule, etc., presume autism and are used to substantiate its severity.
Other screening tools that encompass a broader variety of possible developmental disorders, such as Differential Assessment of Autism and other Developmental Disorders (DAADD, Richard & Calvert, 2003), need to be considered. DAADD identifies pertinent childhood behaviors that can be used to discriminate among developmental disorders. Most childhood developmental disorders have common features, that become more distinct over time. With early intervention, some of the characteristics should resolve, while the remaining features allow better differentiation of a developmental disorder.
The DAADD includes observation of the developmental areas of language, pragmatic/social, sensory, motor (gross and fine), medical/physical involvement, and behavior. Disorders included for consideration are the autism spectrum (Asperger, autism, Rett, pervasive developmental disorder–not otherwise specified), as well as processing/language-learning disability, mental retardation, and other medical syndromes. The results assist a professional to pursue more specific assessment for possible developmental disorders that are indicated at a 40% level or higher. The DAADD also builds awareness for both parents and professionals regarding the considerable overlap among disability characteristics during the preschool years. Finally, the profile of characteristics of concern in the developmental areas evaluated (i.e., language, social, motor, sensory, physical, behavior) become the target goals for the subsequent treatment plan.
The Vineland Adaptive Behavior Scale is another standardized, open-ended interview assessment tool designed to evaluate domains of socialization, communication, motor, and daily living skills (Sparrow, Balla, & Cicchetti, 1984). It is important that the assessment information encompass all developmental aspects, not just speech/language, to develop comprehensive treatment goals.
SLPs have a responsibility to help educate parents and other professionals in discriminating features of ASD versus other developmental disorders to arrive at an accurate diagnosis. A Web-based autism video glossary provides more than 100 videoclips that help parents and professionals recognize the early symptoms of autism. Amy Wetherby of Florida State University and Nancy Wiseman of First Signs created this resource. (Users must register but may access the glossary at no charge.)
Diagnosis and Intervention
Successful treatment is dependent on accurate diagnosis. The ASHA guidelines (ASHA, 2006c) state that the SLP is an independent health care provider with responsibilities in screening, diagnosis, and evaluation of autism. According to the ASHA policy documents, SLPs who acquire and maintain the necessary knowledge and skills can diagnose ASD, typically as part of a diagnostic team. SLPs practicing in public schools need training in the clinical criteria for ASD; they also need to be comfortable with and experienced in using and interpreting reliable, valid ASD diagnostic assessment tools.
SLPs working with ASD must be cautious about presuming specific deficits based on a diagnostic label. Every individual within ASD will share basic core characteristics but also will present a unique compilation of the features. Practicing professionals need to understand the neurological aspects in conjunction with the behavioral symptoms to reliably diagnose difficulties and design intervention goals.
One particularly challenging differential diagnosis is Asperger's syndrome versus nonverbal learning disorder (NVLD). Researchers have theorized that 80% of individuals with Asperger's syndrome also present with characteristics of NVLD, suggesting that these are clinically overlapping disorders related by their neurological site. The fibers that link the cerebellum, basal ganglia, and prefrontal lobes are responsible for inhibitory control over executive functions such as thoughts, attention, and action. Deficits in this area result in too much communication among these areas of the brain, too little inhibition, and a tendency to shut out the rest of the world (Casanova, Buxhoeveden, Switala, & Roy, 2002).
Differentiating ASD from NVLD illustrates the importance of ensuring that treatment is consistent with the etiology of ASD, which is biochemical and neurological in origin. Patience and routine are paramount in every intervention plan. The treatment goal should have a functional impact that the person understands. Give the individual time to adjust to the stimuli, don't overwhelm the individual's sensory system, and keep data to guide your treatment decisions and progress.
Commercial treatment methodologies for ASD are marketed aggressively to parents and school systems. An SLP can help objectively evaluate the variables targeted in a program to make sure they are a match for the individual's profile (for questions to ask in evaluating programs, products, and procedures, visit the ASHA Web site.). Autism occurs on a continuum of severity and causes. One treatment program will not address all individuals with ASD. If not carefully evaluated, an intervention approach can result in wasted time, energy, and money, or may cause harm to an individual with ASD.
ASD is a syndrome disorder, implying deficits in multiple developmental areas. The SLP is a critical member of the multidisciplinary team and must work in conjunction with other professionals. Team members must collaborate on goals and ensure consistency across all settings to achieve a functional impact, as treatment that occurs in isolation will not generalize to other settings.
Empirical research to justify specific treatment approaches is significantly limited because of the multiple behavioral characteristics that are encompassed under the autism spectrum. Genetic analysis of various chromosomes, gender differences, environmental factors, biochemical balance, communication between various neurological structures, and developmental mutations are just a few of the aspects of ASD being evaluated.
While the evidence is being built, the professional must stay informed of research studies and carefully integrate findings into clinical practice. Participation in continuing education activities is required to remain current with the most recent advances in ASD.