Early Screening for Autism in Child Health Care Services

Special Article - Autism in Children

Austin J Autism & Relat Disabil. 2017; 3(1): 1038.

Early Screening for Autism in Child Health Care Services

Haglund N¹*, Dahlgren SO², Gustafsson P¹, Råstam M¹ and Källén K3

¹Department of Clinical Sciences Lund, Child and Adolescent Psychiatry, Lund University, Sweden

²Department of Psychology, University of Gothenburg, Sweden

³Department of Clinical Sciences Lund, Obstetrics and Gynecology, Center of Reproduction Epidemiology, University of Lund, Sweden

*Corresponding author:Nils Haglund, Department of Clinical Sciences Lund, Child and Adolescent Psychiatry, Lund University, Baravägen 1C, SE-22185 Lund, Sweden

Received: April 08, 2017; Accepted: July 06, 2017; Published: July 14, 2017


The Observation Scale for Autism (OSA) was designed to be used as a level 1 screening instrument for Autism Spectrum Disorders (ASD) in primary health care for children. The time-efficient instrument, suitable for children under 3 years, was performed as a complementary assessment for early signs of ASD, in the existing 30- month, follow- up program in the Swedish Child Health Care (CHC) services. In total, 2571 children were screened for ASD with the OSA. A majority of the children (89%) was assessed with both OSA and the Modified Checklist for Autism in Toddlers (M-CHAT). When screened at 30 months´ with the OSA, 35 children (1.4%), reached the cut- off for suspected ASD. Information on ASD diagnoses was retrieved from the Child and Adolescent Psychiatry (CAP) clinics, and all children were followed to at least 6 years (mean 7.3). Among the screened children, 26 (1.01%) were diagnosed with ASD. In this naturalistic setting, both the OSA and the M-CHAT showed low Positive Predictive Value (PPV) as “stand-alone-instruments” (PPV=14% and 7%, respectively) in detecting ASD in children. The M-CHAT showed a higher sensitivity than the OSA (41% vs 19%), but had a higher false positive rate (93% compared to 86%). If combined (screen positive OSA and screen positive M-CHAT), the test results showed acceptable PPV but very low sensitivity. When used in the current clinical setting, none of the instruments, neither used one by one nor used in combination, showed satisfying ability to identify children at risk for ASD.

Keywords: Screening; Autism; Level 1; Child Health Care; Evaluation; Recommendation


OSA: Observation Scale for Autism; ASD: Autism Spectrum Disorders; CHC: Child Health Care; M-CHAT: Modified Checklist for Autism in Toddlers; CAP: Child and Adolescent Psychiatry; PPV: Positive Predictive Value; AAP: American Academy of Pediatrics; USPSTF: U.S. Preventive Services Task Force; JA-OBS: Attention Ability –Observation –test; NH: Nils Haglund; SOD: SvenOlof Dahlgren; ADOS: Autism Diagnostic Observation Schedule; ADI: Autism Diagnostic Interview; WPPSI-R: Wechsler Preschool and Primary Scale of Intelligence-Revise; DSM-IV: Diagnostic and Statistical Manual of Mental Disorders, 4th ed; DSM 5 (5th ed); NPV: Negative Predictive Value; UK NSC: UK National Screening Committee


Early detection of Autism Spectrum Disorders (ASD) has over the last decades become of uttermost interest for Child Health Care due to the increasing evidence that early interventions improve the social and communicative skills of children with ASD [1,2]. The impact of early intervention on alleviation of autism symptoms [3,4], stress the importance to develop an efficient autism screening system for early detection of autism. Different screening instruments, tools and questionnaires have been developed, with the Modified Checklist for Autism in Toddlers (M-CHAT) [5] as one of the most frequently used in finding children at risk for ASD in early childhood. There is and has been a discussion for and against a general screening (level 1 screening) for ASD at 18 or 24 months of age. Level 1 screening include all children regardless of suspicion of ASD, and differ from level 2 screening which include children who are already identified at increased risk due to family history or concerns from parents or clinicians. The American Academy of Pediatrics (AAP) made a statement in 2007 to support a universal screening for ASD at early age [6]. The basis for this recommendation was existing evidence of ASD symptoms at 18 months, the intensive research for developing early ASD- screening tools, and the growing number of effective early intervention programs [7]. The statement made by AAP was questioned by some scientists and practitioners [8,9], who found the evidence too weak to warrant a general ASD screening, and the interest for an implementation in pediatric practice has shown to be modest.

In 2016, the U.S. Preventive Services Task Force USPSTF [10] concluded that there was still insufficient evidence to balance the benefits and harms of screening young children for ASD in early ages as a general health care service. The USPSTF found adequate evidence that current available screening tests could detect ASD in children aged 18-30 months. However, they concluded that there was not enough evidence on benefits for a general screening for ASD when no concerns are raised from family members, other care givers or care professionals. The USPSTF concluded that evidence was lacking, of poor quality or conflicting. On the other hand, the risk of harms of screening for ASD was considered as minimal [10]. The USPSTF found no study that assessed or addressed harm of screening for ASD. Still, the review state “issues that affect families in whom children receive early false-positive screens for ASD are not described in the literature and certainly warrant further consideration”. Furthermore, the UPSTF concluded that to the best of their knowledge, there was no screening method available that could be proven cost-effective, especially in the light of the high false positive rate reported. In UK, the National Health Service made a statement against universal screening for ASD in 2011 [11].

Over the last decades, the autism spectrum was expanded to include children with milder symptoms, which has resulted in an increasing number of children diagnosed with ASD [12]. This fact challenges existing screening instruments in finding the right children for further neuropsychiatric evaluation. Different studies have reported difficulties detecting children with milder forms of ASD symptoms at younger ages, especially in under-served populations where parents’ concerns might not be raised due to cultural background and ethnicity [13,14]. Recommendation of a universal screening for neurodevelopmental disorders in primary practice, when concerns from parents or family are not raised, challenge the quality of the instrument and the overall screening procedure. A screening tool with low sensitivity has difficulties to identify children at risk for ASD whereas an instrument with low specificity will result in an unnecessary large number of children to be referred for further assessment. The quality of the screening tool can be measured by its sensitivity and specificity, which both should exceed 0.70 [15]. In the usually strained primary Health Care Services, a future universal screening of all children for ASD (level 1) must be based on a nontime consuming and easy to handle screening procedure.

Although a number of screening instruments for detection of ASD has been developed over the last decades, there are still only few scales available for assessment of symptoms in children before 3 years in a general setting. Most of the existing instruments are based on parent-reported questionnaires to be used either solely [16-21], or in combination with observation scales [22,23], or are designed to be used as level 2 instruments [24,25]. Existing instruments are often expected to be used by trained nurses, and are not designed to be used in universal, level 1- child health care clinical settings. A recent review [15] evaluating existing level 1 screening instruments for ASD found support for the use of ASD- specific screening at 18 and 24 months, but concluded that screening before 24 months was associated with higher false- positive rates than screening after 24 months. The M-CHAT is the most frequently used instrument in community settings, and has been internationally evaluated. When the screening tool is used as a stand-alone instrument, the Positive Predictive Value (PPV) for the M-CHAT has been reported to be as low as 0.06 [26]. If the M-CHAT was followed by an interview, the PPV has reported to be as high as 0.57 - 0.65 in different universal clinical settings [15]. The PPV was reported to be lower in younger children, aged 16-24 months (0.28) compared to 24-30 months old ones (0.61). A Swedish study [23] evaluated the M-CHAT in combination with the Joint Attention Ability Observation –Test (JA-OBS), followed by parent interview. Only M-CHAT test-positive children were assessed by the observation tool (JA-OBS). The study yielded high PPV (90%) for detecting ASD, but was not included in the previously quoted review. To the best of our knowledge, the sensitivity of the M-CHAT has not yet been assessed in a clinical setting.

It has been reported that existing screening tools depending on parents’ observation abilities often have unsatisfactory value in discriminating between ASD and non-ASD within the group of children showing atypical development [27]. Although some appropriate screening tools for early detection of ASD have been developed and shown to have good psychometric properties, there is still a need for brief, easy to handle assessment instruments designed for use in the primary health care system. Our research team developed the OSA (Observation Scale for Autism) [26], designed to be a time- efficient observation scale, easy to administer, and suitable for children under 3 years. The instrument was designed to perform independently of social, language, and cultural background. The mentioned requirement was especially important when the diagnostic tool should be used in the multicultural city of Malmö. The instrument was developed to be a part of the existing 30- month, follow- up program in the Swedish Child Health Care (CHC) services, offered free to all children. To the best of our knowledge, we are not aware of any true level-1 screening study in which all children were tested with an observation instrument.

The results from a pilot study evaluating the OSA [28], suggested the instrument to be able to discriminate children with ASD from children with typical development, and from children with Down syndrome. The latter group was included to evaluate the performance of the OSA in a group of children with developmental delay. According to the pilot study, using a suggested cut-off (scoring negative in 3 items or more), the OSA provides high sensitivity for ASD (92%) with low false-positive rates.


The aim of the present study was to evaluate the OSA as a level-1 instrument in the Swedish primary health care universal 30 months’ follow-up to detect signs of ASD in children. Screen positive children were supposed to be referred for diagnostic evaluation at the Child and Adolescent Psychiatry (CAP) clinic. A second aim was to compare the performance of OSA with that of the M-CHAT (which was used parallel with the OSA).

Material and Methods


The OSA was developed by the two first authors (NH, SOD). Items for the observation scale were chosen according to research in early markers for ASD [29-31]. In cooperation with the nurses at two CHC-units in Malmö, the OSA was adapted to be suitable for the standard 30- month assessment of all children in the primary Child Health Care program in Sweden. The OSA was designed to be used as a part of the universal examination, and had to be easy to administer, non-time consuming, and requiring minimal formal training for the CHC-nurses.

The OSA was earlier presented and described [26] and consists of 12 observations, focusing on the observation of behavior of the child´s ability to interact with his/her parent(s) and the CHCnurse. Observations are especially focused on reciprocal behavior in communication and social interaction and play, namely; reciprocal social interaction between caregiver and child; reciprocal eye contact between nurse and child during the assessment; reciprocal play between nurse and child; the child’s spontaneous use of two word phrases during assessment. The observers were instructed to determine whether the child behave at each observation point as expected for a child with the developmental age of 30 months. If not, the observer would mark a negative score for the item in question. When evaluating the OSA instrument [28], the research team selected the 9 most discriminative items to increase specificity (excluding from the original 12 observations; adequate movements, building blocks and two-word- sentences). The 9- item version of the OSA was used in the current study.


As a first step, the OSA was tried at two CHC-units with different populations according to social and language background in Malmö. After that, the screening instrument was offered to be used at all CHCunits in the Malmö area. Malmö is a city with a diverse population regarding cultural, social, and language background. In 2015, more than 50% of all children under the age of 16 years had a mother born outside the Nordic countries, and the proportion of immigrants is increasing [32]. Out of 29 CHC-units, 21 units chose to participate, in an up to a two-year period screening of all children at their 30-months follow-up health assessment. Different CHC-units participated in the screening program for varying long periods according to agreements made. The over-all screening period lasted during January 2011to May 2013 (29 months), but few CHC centers participated during the whole screening period. In total, 2,571 children were screened with OSA out of 6,450 children who attended the 30-month follow- up at any participating CHC (Figure 1 & Table 1). A majority of the CHCnurses participated in a one-day course on the early symptoms of ASD, and received information on how to use the OSA instrument.