Altered Cervical Vestibular-Evoked Myogenic Potential in Children with Attention Deficit and Hyperactivity Disorder

Arousal dysregulation and executive dysfunction in attention deficit hyperactivity disorder (ADHD)

Attention deficit/hyperactivity disorder (ADHD) is a heterogeneous neurodevelopmental condition, that continues to have an elusive etiological background. A number of extant models and theories have historically intended to explain the many factors contributing to ADHD behaviors. One of the most accepted hypotheses has been the executive dysfunction theory associating reduction in executive control to abnormalities in structure and operational dysfunction of dopaminergic signaling networks. Nevertheless, executive functions are not always impaired in ADHD, and the literature describes other symptoms commonly reported suggesting individuals with ADHD would appear to suffer from a more general deficit. Another existing line of research, that has gained much attention recently, establishes that ADHD would have dysregulated states of brain arousal that would account for its commonly observed cognitive deficits and behavioral symptoms, described as the state regulation theory, which has now included measures of autonomic function. This article describes some important aspects that compose and challenge these two most influential theoretical constructs, executive dysfunction and state-regulation, based on their empirical evidence, implying the need to reevaluate the norms used to classify individuals and establish ADHD diagnosis. Large number of controversial results continue to exist within the study of ADHD biological and/or performance markers, possibly due to such heterogeneity and variability within the same diagnosis. The need to resolve these issues and establish newly revised diagnostic criteria for ADHD is critical, as therapeutic success depends on having accurately identified underlying neurophysiological factors in order to appropriately address them in treatment.

Relationships between sensory integration and the core symptoms of attention-deficit/hyperactivity disorder: the mediating effect of executive function

Attention-deficit/hyperactivity disorder (ADHD) is often accompanied by executive function deficits and functional alterations in sensory integration. The present study aimed to investigate the relationship between ADHD core symptoms, executive function, and sensory integration in children with ADHD. A total of 228 children with ADHD were recruited for our study. The Sensory Organization Test (SOT) and Child Sensory Integration Scale (CSIS) evaluated the sensory integration ability from lab-based and scaled-based perspectives, respectively. Three core components of executive functions (inhibition, working memory, and set-shifting) were assessed using both lab-based tests and the relevant factors from the behavior rating inventory of executive function (BRIEF). Partial correlation analysis was performed to explore the correlation of sensory integration with EF and ADHD core symptoms. Based on the observed significant correlation, bootstrap analyses were further conducted to explore the potential mediating effect of EF on the relationship between sensory integration and ADHD core symptoms. ADHD symptoms and EF were significantly correlated with CSIS scores; no factors were significantly correlated with SOT performance. In detail, the vestibular-balance score was negatively correlated with both inattention and hyperactivity/impulsivity symptoms, while the hyper-sensory and proprioception scores were negatively correlated with only inattention symptoms. For the scaled-based EF, vestibular-balance was negatively correlated with inhibition and working memory, and the hyper-sensory score was negatively correlated with shift factor. No correlation was found for the lab-based EF tests. The subsequent mediation analysis found that inhibition partially mediated the relationship between vestibular balance and hyperactivity/impulsivity symptoms. Working memory completely mediated the relationship between vestibular-balance, hyper-sensory, proprioception, and inattention symptoms. These results were well validated in an independent sample. Our present findings demonstrated that the functional alteration in basic sensory integration might be associated with impairments of executive functions and then lead to the behavioral expression of ADHD. The present findings might provide a new perspective to understand the occurrence of ADHD symptoms and potential precise intervention methods.

Vestibular Evaluation of Children Diagnosed with Specific Learning Disorder

Objective

The aim of this study was to determine the vestibular function of children diagnosed with specific learning disorders (SLD).

Methods

This study was conducted with 30 children diagnosed with SLD and 30 healthy children matched for age and sex, and vestibular tests were applied.

Results

Optokinetic and head shake test values in videonystagmography subtests were found to be pathological in the study group, and the lateral asymmetry value in video head impulse test (v-HIT) was found to be significantly higher in the study group. Also, a significant difference was found in the N1 latency, P1-N1 interlatency, P1-N1 amplitude values in the cervical vestibular evoked myogenic potential test, and asymmetry values in the ocular vestibular evoked myogenic potential test.

Conclusion

The current study showed that vestibular functions may differ from normal in SLD patients and that vestibular dysfunction may play a role in symptoms such as postural instability, balance, and gross and fine motor disorders that are frequently observed in these children.

Gait in children with and without ADHD: A systematic literature review

BACKGROUND

There is increasing speculation whether Attention-Deficit/Hyperactivity Disorder (ADHD) has phenotypic or secondary motor symptoms. Some evidence suggests even fundamental motor skills such as walking can differ in ADHD, however, the evidence is limited and has not been reviewed. Therefore, we conducted a systematic review to summarize the findings regarding gait in ADHD compared to typically developing children in (1) normal (i.e., self-paced), (2) paced or complex (i.e., walking backwards), and (3) dual-task contexts.

METHOD

Following a thorough literature search and application of stringent exclusion criteria, a total of 12 studies were included in this review. All studies examined normal walking with a variety of gait parameters in children (age range: 5-18), however, selected parameters and group differences were often inconsistent.

RESULTS

In self-paced walking, studies reporting gait with coefficients of variance (CVs) indicated several between-group differences, whereas averages of gait variables were the same for those with ADHD and typically developing children. Paced or complex walking contexts often differed between ADHD and typically developing groups, favoring the ADHD group in some cases, but primarily the typically developing participants. Finally, walking contexts with dual-tasks showed more frequent performance losses in the ADHD group.

DISCUSSION

Children with ADHD seem to have specific patterns of gait variability compared to typically developing children, particularly in complex walking contexts and at faster paces. The influence of age, medication, and method of gait normalization may have influenced the results of studies. Overall, this review highlights the potential for a unique gait profile in children with ADHD.

Stabilometric Biofeedback Training in Cognitive and Affective Function Improvement. Contribution of the Russian Scientific School. Part II

This review is the second part of the critical analysis of recent papers of Russian and other authors devoted to the study of the stabilometric parameters in postural control biofeedback training and rehabilitation, associated with psychological functions. The review presents the studies of postural control features in chronic pain syndrome, chronic fatigue syndrome, Parkinson’s disease, multiple sclerosis, and depression. The leading role of Russian researchers in the development and application of stabilometric biofeedback in the training of optimal functioning, rehabilitation, and correction of neurological disorders is noted. The paradigm of stabilometric biofeedback training of the cognitive and affective functions is offered.

Feasibility and Preliminary Effects of a 1-Week Vestibular Rehabilitation Day Camp in Children with Developmental Coordination Disorder

AIM

This pilot study investigated the feasibility and preliminary effects of an intensive 1-week day camp program for children with Developmental Coordination Disorder (DCD) that focused on vestibular rehabilitation.

METHODS

Ten participants (6-10 years) were assessed twice pre-intervention, post intervention, and at 8-week follow-up. Videonystagmography, Video Head Impulse Tests (vHIT), and Modified Emory Clinical Vestibular Chair Test (m-ECVCT) test were assessed at baseline. Outcomes measures were gaze stability (Dynamic Visual Acuity; DVA), functional gait (Functional Gait Assessment; FGA), balance (Sensory Organization Test), motor function (Bruininks-Oseretsky Test), and participation (Miller Function and Participation).

RESULTS

No abnormal results were detected from the videonystagmography, vHIT and m-ECVCT. There was a 100% attendance rate at the camp and assessment sessions. FGA scores significantly improved following intervention and changes were maintained at follow-up. The number of children with abnormal DVA scores decreased from 3 to 1 to 0 between pre-intervention, post-intervention, and follow-up. There were no significant changes in any of the other outcomes following intervention.

CONCLUSIONS

Intensive vestibular rehabilitation delivered in a day camp format is feasible and show positive preliminary effects on functional gait and dynamic visual acuity in children with DCD.

Evaluation in Ayres Sensory Integration® (EASI) Vestibular and Proprioceptive Tests: Construct Validity and Internal Reliability

IMPORTANCE

Vestibular and proprioceptive functions play a critical role in occupational performance and participation. Assessment of these functions in a reliable and valid manner is part of a comprehensive assessment in the Ayres Sensory Integration® frame of reference, commonly applied in pediatric occupational therapy.

OBJECTIVE

To report on reliability and validity of six tests of vestibular and proprioceptive functions of the Evaluation in Ayres Sensory Integration (EASI).

DESIGN

We used Rasch analyses to examine and modify the number of items and scoring categories on the six tests and known-groups analysis to examine group differences. We evaluated internal consistency using Cronbach's α and Rasch person reliability.

PARTICIPANTS

The sample contained typically developing children (n = 150) and children with sensory integration concerns (n = 84); all participated voluntarily. Outcomes and Measures: The EASI is used to measure sensory and motor functions in children ages 3 to 12 yr. The six tests of vestibular and proprioceptive functions were analyzed in this study.

RESULTS

Data from >96% of items conformed to the expectations of the model. We found statistically significant group differences (ps < .001-.128; ds = 0.20-1.31), with the typically developing children group scoring significantly higher on all but one test, and moderate to strong evidence of internal consistency (Rasch person-reliability indices ≥ 0.80; strata > 3) for five of six tests.

CONCLUSIONS AND RELEVANCE

The EASI vestibular and proprioceptive tests have strong construct validity and internal reliability, indicating that they are psychometrically sound clinical measures. What This Article Adds: The development of occupational therapy assessments with strong psychometric properties, such as the EASI tests of vestibular and proprioceptive functions, enhances clinical practice and research by elucidating the factors affecting participation in accurate and dependable ways so that occupational therapy interventions can be focused and effective.

Weak Vestibular Response in Persistent Developmental Stuttering

Vibrational energy created at the larynx during speech will deflect vestibular mechanoreceptors in humans (Todd et al., 2008; Curthoys, 2017; Curthoys et al., 2019). Vestibular-evoked myogenic potential (VEMP), an indirect measure of vestibular function, was assessed in 15 participants who stutter, with a non-stutter control group of 15 participants paired on age and sex. VEMP amplitude was 8.5 dB smaller in the stutter group than the non-stutter group (p = 0.035, 95% CI [−0.9, −16.1], t = −2.1, d = −0.8, conditional R² = 0.88). The finding is subclinical as regards gravitoinertial function, and is interpreted with regard to speech-motor function in stuttering. There is overlap between brain areas receiving vestibular innervation, and brain areas identified as important in studies of persistent developmental stuttering. These include the auditory brainstem, cerebellar vermis, and the temporo-parietal junction. The finding supports the disruptive rhythm hypothesis (Howell et al., 1983; Howell, 2004) in which sensory inputs additional to own speech audition are fluency-enhancing when they coordinate with ongoing speech.

Vestibular Functioning in Children with Neurodevelopmental Disorders Using the Functional Head Impulse Test

Several studies in children with neurodevelopmental disorders (NDDs) including autism spectrum disorders (ASDs), reading impairment, or attention deficit/hyperactive disorder (ADHD) pointed toward a potential dysfunction of the vestibular system, specifically in its complex relationship with the cerebellum. The aim of the present study was to test the functional vestibulo-ocular reflex (VOR) responses in children with NDDs to measure functional performance of the vestibular system. The VOR is specifically involved in this stabilization of the image on the retina during rapid movements of the head. To perform this study, four groups of children with ASD, ADHD, reading impairment, and with neurotypical development (TD) were enrolled (n = 80). We performed the functional head impulse test (fHIT), which measured the percentage of correct responses by asking the child to identify an optotype briefly presented during passive head impulse in each direction of each semicircular canal plane. We observed significantly lower correct answers in children with NDDs compared with those with TD (p < 0.0001). Surprisingly, there was no significant difference between the three groups of children with NDDs. Our study fostered preliminary evidence suggesting altered efficiency of vestibular system in children with NDDs. VOR abnormalities estimated using the fHIT could be used as a proxy of NDD impairments in children, and represent a potential biomarker.

Neural Foundations of Ayres Sensory Integration®

Sensory integration, now trademarked as Ayres Sensory Integration^® or ASI, is based on principles of neuroscience and provides a framework for understanding the contributions of the sensory and motor foundations of human behavior. The theory and practice of ASI continues to evolve as greater understanding of the neurobiology of human behavior emerges. In this paper we examine core constructs of ASI identified in the seminal work of Dr. Jean Ayres, and present current neuroscience research that underlies the main patterns of sensory integration function and dysfunction. We consider how current research verifies and clarifies Ayres’ propositions by describing functions of the vestibular, proprioceptive, and tactile sensory systems, and exploring their relationships to ocular, postural, bilateral integration, praxis, and sensory modulation. We close by proposing neuroplasticity as the mechanisms underlying change as a result of ASI intervention.

Considerations for Testing and Treating Children with Central Vestibular Impairments

This perspective explores common pediatric diagnoses that could present with central vestibular pathway dysfunction, leading to delays in motor development and postural control, and gaze instability. Specifically, the following diagnoses are considered: cerebral palsy, myelomeningocele, vestibular migraine, attention-deficit hyperactivity disorder, developmental coordination disorder, concussion, childhood cancer, congenital muscular torticollis, adolescent idiopathic scoliosis, and autism. Suggestions for clinical screening, vestibular function testing, and vestibular rehabilitation for children with these diagnoses are based on evidence for the efficacy of testing and interventions for children with peripheral vestibular hypofunction. More research is needed to explore peripheral and central vestibular function in children with these diagnoses. Testing and intervention methods may need to be modified to accommodate for the specific behavior and motor challenges that some children might present. Researchers should develop technology so that gaze stabilization exercises can be delivered in a fun, functional, and effective way.