1. Introduction
Neurodevelopmental disorders are a group of disabilities that are primarily associated with functional disturbances of the brain and neurological system. They encompass a wide range of disorders, including autism spectrum disorder (ASD), attention deficit and hyperactivity disorder (ADHD), intellectual disability (ID), and motor, communication, learning, and language disorders [
1]. Estimates of the prevalence of developmental disability differ among various populations and settings according to different methodological approaches. Data from a study in the United States estimated a prevalence of 15.04% for any developmental disability in children aged 3 to 17 years old [
2]. Among them, ADHD was one of the most prevalent disorders. In 2015, a meta-analysis of 175 studies reported an overall pooled estimate of 7.2% [
3]. The Saudi National Mental Health Survey (SNMHS) estimated that the lifetime prevalence and 12 month prevalence of ADHD in Saudi Arabia are 8% and 3.2%, respectively [
4,
5]. The prevalence of ASD worldwide was estimated to be approximately 52 million cases according to the Global Burden of Disease study in 2010, equivalent to 1 in 132 individuals [
6]. In Saudi Arabia, data on the national prevalence of ASDs are scarce. A few studies have cited a prevalence of 18 per 10,000 and one in 167 individuals [
7,
8].
People with neurodevelopmental disorders experience difficulties in multiple domains, including cognition, learning, language and speech, and sensory, motor, and behavioral problems, thus prompting the need for comprehensive multidisciplinary assessments and interventions [
9]. The evidence is abundant for the benefits of early diagnosis and intervention for neurodevelopmental disorders, leading to better functional outcomes [
10]. This field faces multiple challenges in the Arab region, particularly in Saudi Arabia, which can be attributed to factors such as the scarcity and limitations of epidemiological studies, the shortage of trained professionals, and late access to diagnosis and early interventions [
8,
11].
Cognition is one of the domains commonly affected in people with neurodevelopmental disorders; it refers to the mental processing of information, including attention, memory, learning, decision making, reasoning, and problem solving. There is a high degree of heterogeneity in the underlying cognitive impairment in these disorders; furthermore, the high rates of comorbidity between them complicate the degree and extent of these problems, imposing even more challenges for research and clinical practice [
12]. People with autism experience specific deficits in processing social and emotional information, which are common diagnostic features of ASD [
13]. Furthermore, there is considerable comorbidity between ASD and ID. Some authors reported that 31% of children with ASD have comorbid ID [
14]. In ADHD, the cognitive deficits frequently reported include executive dysfunction and information processing speed, and many individuals with ASD and ADHD scored lower in working memory and processing speed in intelligence testing [
15]. The assessment of a child’s intellectual ability is considered a standard part of the evaluation of people with neurodevelopmental disorders worldwide [
16], and even though it comes with its challenges, given the unique cognitive profile of an individual with these disorders, intelligence testing scores can play a role in designing a personalized care plan and placement into clinical and educational settings [
17].
In terms of sensory functioning, children with neurodevelopmental disorders respond differently to sensory experiences than typically developing peers [
18]. There is abundant evidence of sensory dysfunction in people with ASD, reflected by including sensory aspects in the latest Diagnostic and Statistical Manual of Mental Disorders (DSM-5) [
1]. Many people with ASD experience sensory processing dysfunction (SPD), as it is challenging to receive, organize, and interpret sensory stimuli from various sensory systems [
19]. These experiences may appear as hyper, hyperreactivity, or seeking a particular sensory stimulus. It is estimated that as high as 90% of people with ASD have sensory abnormalities [
20]. A study among 64 children diagnosed with ASD in Riyadh, Saudi Arabia, found that 84% had significant sensory dysfunctions [
21]. In ADHD, several reports suggest the presence of abnormal sensory processing in multiple domains when comparing ADHD with control groups [
22]. A study comparing the sensory profiles of children with ADHD or ASD and typically developing children found that ADHD and ASD were associated with more sensory processing deficits than children without disabilities [
23]. The presence of sensory dysfunctions in children with neurodevelopmental disorders implicates their daily activities, interactions, and learning experiences [
24]. These findings reflect the vitality of an assessment for early detection, paving the way for evidence-supported early intervention programs [
25]. Even though SPD is largely seen in people with different NDDs, a specific pattern for each disorder has not established yet. In addition, people sharing the same condition also showed different sensory processing patterns. This might be related to the different sensory thresholds and coping strategies in each individual. Moreover, additional factors, such as age, gender, and being medicated, play a role in this variation of sensory processing within people with the same condition [
26,
27,
28,
29].
Language and speech are among the domains that are frequently affected in children with neurodevelopmental disorders. Communication delays are often among the first issues that indicate ASD [
30]. However, there is high heterogeneity in the ability of children with ASD to understand and use language [
31], with some children experiencing severe language impairment, while other children’s language abilities are comparable to typically developing children [
32]. Multiple levels of speech and communication can be affected, including nonverbal (e.g., facial expressions, gestures, and eye contact), paralinguistic (e.g., prosody and intonation), and linguistic level (e.g., language and speech). Deficits in the social use of speech and language are particularly prominent in people with ASD. Furthermore, in a systematic review of 21 studies, children with ADHD were found to have poorer language function than controls in multiple language domains, including overall language performance, expressive, receptive, and pragmatic languages [
33]. Language and speech problems can result in several adverse outcomes, such as behavioral difficulties, poor adaptive skills, poor social skills, and poor academic function [
34,
35]. However, the earlier a child acquires speech and language skills, the better the outcomes are in adaptive and social functioning [
36]. Furthermore, some evidence suggests a lower efficacy of such intervention when applied after five years, which emphasizes the importance of earlier detection and management [
37].
Children with neurodevelopmental disorders present with complex issues affecting multiple aspects of their development. This asserts the role of multidisciplinary team evaluation in addressing these issues. This study aimed to explore the findings of a multidisciplinary team assessment of children referred for possible neurodevelopmental disorders.
5. Discussion
In this study, we explored the findings of a multidisciplinary assessment of 221 children referred for the assessment of possible neurodevelopmental disorders. Two-thirds of the referred children were diagnosed with ASD, followed by ADHD in 10%, and 8.5% were not diagnosed with neurodevelopmental disorders. When assessed for comorbidities, 46 children had comorbid ADHD in addition to the primary diagnosis. Children with an NDD show high comorbidities, especially with other NDDs. Some studies found that 40 to 80% of individuals with ASD also have ADHD [
43]. In this study, the male-to-female ratio in our sample was 2.8 boys to one girl. This result is consistent with the prevalence ratio in the literature for neurodevelopmental disorders, which varies between two and four males to one female [
44]. Similar to these findings, two Saudi Arabia studies reported a ratio of 2.7:1 and 3.5:1 boys to girls, respectively, among children diagnosed with ASD [
11,
45].
Parental consanguinity is a prevalent phenomenon in Saudi Arabia and the Middle East, with previous studies from SA reporting a prevalence between 28.5% and 39% of the consanguineous relationship between the parents of children with ASD [
11,
45,
46]. In the current study, the consanguinity rate was 51.1%, exceeding that of the studies mentioned above. This variation could partly be attributed to our sample’s heterogenicity, as there were multiple neurodevelopmental disorders in addition to ASD, compared to sample populations of ASD only in the previous studies. This gap in the relationship between consanguinity and neurodevelopmental disorder among the Saudi population is worth highlighting, and future research on this issue is recommended. Another finding of this study is the history of mental illness in 26.6% of first-degree relatives. A cohort study in Sweden found an increased risk of autism when there is a family history of multiple mental and neurological disorders [
47]. These results also align with multiple studies that found an increased risk of ASD in children with a history of mental illness in first-degree relatives [
48,
49]. This study found that approximately half of the patients with an NDD (52.7%) had a history of psychiatric medication use, which is higher than a previous study from Saudi Arabia, which only found that 39.08% of children with ASD were on psychiatric medications [
50]; a range between 2.7% and 80% has been reported in the literature [
51]. This increase in psychiatric medication use could be partly related to the limited access to nonpharmacological services for children with NDDs.
Social communication and language delay are among the most frequently reported concerns in children with NDD. In the current study, most children were found to have low communication and socialization skills and language delays. Furthermore, most children who went through speech and language assessment demonstrated poor levels of pre-communication and nonverbal communication skills. It has been estimated that approximately 30% of children with ASD have minimal verbal abilities and varying degrees of severity in communication and language impairments [
52]. Multiple studies reported social communication impairments and language delay as the most common reason for the referral of children with ASD for assessment [
11,
46,
53].
Cognitive abilities in individuals with NDDs may be a key indicator of long-term outcomes and has an essential impact on developing treatment goals. Only 43 children in this study went through an IQ assessment. Most of those children scored lower than average, with 60% and 44% receiving scores suggestive of ID on Leiter and Stanford-Binet intelligence scales, respectively. Recent studies reported a 30%–50% rate of intellectual disability among children with ASD [
14,
54]. The higher ID rates in our sample may be because only a small number of children had an IQ assessment. The heterogenicity in intellectual functions within the NDD population leads to multiple challenges when considering intervention plans. Reports often indicate that the presence of an intellectual disability is associated with poor social communication and language skills, motor abilities, and slow improvement in the acquisition of daily skills [
55,
56].
The current results found that children with NDD scored high in children and toddler sensory profiles. The most common sensory profiles included avoiding, sensitivity, registration, and seeking domains. These results are similar to those of Narizisi et al. [
52], who found that children diagnosed with autism have a higher prevalence of sensory alteration than typically developing peers in Italy. Another study among Saudi Arabian children, by Al-Heizan et al., reported similar results, with a higher prevalence of sensory dysfunction in children with ASD [
21]. Other studies have pointed to the effect of such sensory difficulties on social communication [
57], more severe restricted and repetitive behaviors [
58], feeding [
59], and sleep problems [
60] in children with NDDs. The results of our current study indicate increased rates of motor difficulties in most children with NDDs, with 31% and 58% scoring below average and low in the motor skills domain, respectively. These results are consistent with previous studies reporting poorer motor skills among children with developmental disabilities [
61,
62]. The increase in both sensory and motor difficulties has been associated with reduced daily living skills performance [
63]. These findings show the importance of sensory and motor assessments of children with NDDs and implementing standard treatment programs with occupational and physical therapy.
In this study, most children with neurodevelopmental disorders had low adaptive behavior composites and scored low in all domains of adaptive behavior skills measured by VABS-II. These results are similar to the reported profiles of children with neurodevelopmental disorders in the literature [
64,
65]. We also explored the daily living skills among children with NDDs. Our results show that most children with NDDs (88%) had low or below-average daily living skills, similar to another study that reported a lack of self-care skills among 82.9% of school-aged children with ASD [
66]. In this sample, most of the children required assistance with most domains of daily living skills (DLS), with bathing, upper body dressing, and toileting requiring the highest level of assistance, followed by grooming, lower body dressing, and eating. These findings are consistent with a Turkish study that assessed the DLS of children with ASD using the WeeFIM II scale [
67]. They reported that their participants needed assistance in most DLS. However, there was a difference in the domains that needed help compared to our sample, with bathing and grooming requiring the highest level of assistance, while upper and lower body dressing required lower levels of assistance. These differences could be due to the inclusion of children with other NDDs and younger ages compared to a sample consisting mainly of children with ASD who were above thirteen years old in the Turkish study.
These findings reflect the need for a multidisciplinary team assessment to address the range of difficulties encountered by children with NDDs. Although the support for better outcomes with an earlier intervention is mixed [
68], multiple studies indicated more robust and beneficial results with early recognition and intervention for people with NDDs [
10,
25]. Our results show that the average age of the referred children was 7.95 years. This is inconsistent with previous results that showed that the average age of an ASD diagnosis was between two and three years of age, reported by previous Saudi studies [
11,
45]. Similar to our findings, a previous Australian study, by Bent et al., reported a later age of diagnosis with an average age of 4 years, and commonly diagnosed at 6 years of age among their sample of children with ASD [
69]. Several factors could contribute to the later age of diagnosis, including a less severe symptomatology, which may not have given rise to early concerns for parents. Another factor to consider is that social communication, attentional, and academic difficulties are indicative of NDD diagnoses and may not have been present until children began to attend kindergartens or preschools. There have been increasing efforts to address these gaps in delayed diagnosis and referrals for assessment and intervention in Saudi Arabia, with the national policy for screening for autism being approved in 2021 [
70]. More recently, a consensus statement by Saudi experts in the field highlighted the importance of both early multidisciplinary team assessment and early interventions for children with autism in efforts to bridge these gaps [
71].