Chronic pain and hypertonia (increased muscle tone) are common issues among neurodivergent populations, significantly impacting their quality of life. Neurodivergent individuals, such as those with attention deficit hyperactivity disorder (ADHD) and autism spectrum disorder (ASD), frequently experience these conditions due to various neurobiological and physiological factors. This article explores the prevalence, underlying mechanisms, and management strategies for chronic pain and hypertonia in these populations.
Individuals with ADHD often exhibit significant motor impairments, which can lead to chronic pain and other physical challenges. The Motor Function Neurological Assessment (MFNU) has been instrumental in identifying these motor problems. The MFNU was developed over three decades to assess motor deficiencies in children with learning and attention difficulties. Studies have shown that children with ADHD often have motor skill problems, with significant overlaps reported between ADHD and developmental coordination disorder (DCD).
Research indicates that children with ADHD frequently exhibit motor impairments such as impaired handwriting, balance issues, and synkinesis (involuntary movements). Initially, motor clumsiness and improvements in motor performance with central stimulants were attributed to inattention and impulsiveness. However, recent studies show that real motor impairments, especially in fine motor skills, are common in ADHD and are intrinsic to the neurobiological dysfunctions associated with the condition.
The MFNU identifies motor deficiencies such as problems in muscular inhibition and heightened muscle tone, particularly in children with ADHD. These deficiencies often manifest in daily activities even if not always detected in standard motor tests. The MFNU includes various subtests to measure dynamic balance, diadochokinesis (rapid alternating movements), reciprocal coordination, thumb movement, ball throwing/catching, walking, lifting limbs, and passive movements of hips and feet. High muscular tone is assessed through palpation and specific muscle tests.
The MFNU has shown high reliability and consistency in measuring motor regulation problems. Studies have demonstrated significant differences in MFNU scores between children with ADHD and controls, with ADHD children showing higher problem scores. These findings suggest that motor regulation problems are prevalent in ADHD and not merely due to comorbid deficiencies in motor skills or inattention. These problems may be intrinsic to ADHD and linked to neurobiological dysfunctions.
Methylphenidate (MPH) has been shown to improve motor function in individuals with ADHD. In one study, a single dose of MPH significantly enhanced motor performance in children with ADHD-C (Combined type). The improvements were observed across all MFNU subtests, including dynamic balance, diadochokinesis (rapid alternating movements), reciprocal coordination, and thumb movement. However, these improvements were temporary and subsided as the medication was metabolized.
Further studies compared MFNU profiles of high MPH responders and non-responders, finding that high responders exhibited significantly higher motor problem scores. This indicates a link between motor regulation problems and the neurofunctional processes modulated by MPH. The improvements with MPH support the connection between motor regulation and ADHD symptoms, suggesting that motor regulation problems in ADHD are closely linked to the neurofunctional processes affected by MPH.
Adults with ADHD also report higher levels of chronic pain compared to controls. This chronic pain is often widespread and significantly impacts daily functioning. Persistent motor regulation problems, leading to increased muscle tone and subsequent pain, are likely contributors to this high prevalence of chronic pain among individuals with ADHD.
Research has shown that adults with ADHD exhibit significantly higher MFNU problem scores and report more widespread and higher levels of pain compared to controls. This suggests that long-term motor regulation problems may contribute to chronic pain in ADHD individuals. These findings underscore the importance of addressing motor regulation issues as part of the comprehensive management of ADHD.
A study on the prevalence of chronic and multisite pain in adolescents and young adults with ADHD compared to the general population found significantly higher rates of chronic pain in those with ADHD. Pain locations commonly included the head, neck, back, and limbs, with the ADHD group reporting higher rates of pain in these areas compared to their peers. Chronic pain was associated with higher levels of psychological distress and lower quality of life in individuals with ADHD.
These findings highlight the significant burden of chronic pain in individuals with ADHD. The reasons for this increased pain prevalence are multifaceted, involving both psychological and physiological factors. Healthcare providers should be aware of the high prevalence of chronic pain in patients with ADHD and consider comprehensive pain management strategies that address both physical and psychological aspects.
Children with Autism Spectrum Disorder (ASD) often face significant challenges with motor skills, which can manifest as hypertonia (high muscle tone) or hypotonia (low muscle tone). Hypertonia is characterized by stiff or tight muscles that resist movement, making daily activities like walking, writing, and playing difficult. This increased muscle tone can lead to rigidity, causing the muscles to be less flexible and more resistant to stretching. This can severely impact a child's ability to perform basic motor functions and maintain proper posture.
In ASD, abnormal muscle tone is prevalent and can significantly impair motor coordination. Hypertonia results in excessive muscle stiffness and resistance, leading to difficulties in bending and reaching out limbs, and maintaining balance. Children with hypertonia may walk with stiff, straight legs and have difficulty performing tasks that require fine motor skills, such as writing or buttoning a shirt. This condition often requires physical therapy and other interventions to manage symptoms and improve motor function.
These motor disorders are frequently observed in conjunction with other neurodevelopmental issues such as hypotonia, where muscles are overly lax or "floppy." Hypotonia is more prevalent in autism than hypertonia and is characterized by reduced muscle tone, leading to difficulties in sitting upright, standing, and other activities that require muscle strength and endurance. This condition can make children appear weak and excessively flexible, with joints that easily dislocate.
The presence of both hypertonia and hypotonia in children with ASD indicates a broader range of motor dysfunctions that can affect various aspects of their physical abilities. Managing these conditions often requires a multidisciplinary approach involving physical therapy, occupational therapy, and sometimes pharmacological interventions to enhance muscle function and coordination.
Pain perception in neurodivergent individuals is often atypical. For instance, individuals with ASD may exhibit both increased and decreased sensitivity to pain. This paradoxical nature of pain perception can be attributed to various neurophysiological factors, including abnormalities in pain processing pathways and altered brain activation patterns. Studies have shown that individuals with ASD might have altered pain thresholds, which can vary widely from being hypersensitive to certain stimuli to having an unusually high tolerance for pain.
The complexities in pain perception among neurodivergent individuals can be linked to the initial stages of pain signaling. Nociceptors, which detect thermal, mechanical, and chemical stimuli, transmit these signals to the central nervous system via different nerve fibers. In ASD, studies on pain thresholds have shown contradictory results, with some individuals exhibiting hypo-sensitivity (reduced sensitivity to pain) and others showing hyper-sensitivity (increased sensitivity to pain). Factors such as attention, anxiety, and task performance can significantly influence these findings.
Brain activity and pain processing also play crucial roles. Structural and functional deviations in the thalamus, a regulatory hub for sensory inputs, have been observed in individuals with ASD. These deviations can lead to altered pain perception and processing. Similarly, changes in the primary somatosensory cortex (S1) affect pain sensitivity and processing. The salience matrix, involving the cingulate cortex, insula, and prefrontal cortex, assigns emotional value to pain and directs attention to pain stimuli. Alterations in these brain regions have been documented in ASD, affecting pain awareness and response.
Studies on empathy for pain in individuals with ASD show mixed results. Some individuals exhibit typical brain activations in response to observing pain in others, while others show atypical reactions. Empathy for pain involves understanding and sharing the emotional experience of pain with another person, which is typically mediated by specific brain regions. However, in individuals with ASD, these responses can be highly variable.
For example, observing pain in others can trigger brain responses like those caused by direct pain experiences. However, in individuals with ASD, these responses can range from typical to highly atypical. This variation highlights the complexity of pain perception and empathy in neurodivergent populations. Some individuals with ASD may have heightened activation in areas like the anterior cingulate cortex during pain anticipation, which can increase sensitivity to anticipated pain. Others may show reduced or atypical responses, reflecting differences in how they process and empathize with pain stimuli.
This mixed response underscores the need for personalized approaches in understanding and managing pain in neurodivergent individuals. Tailoring pain management strategies to individual needs can help address the unique ways in which these populations perceive and react to pain, ultimately improving their overall quality of life.
Managing chronic pain and hypertonia in neurodivergent populations requires a comprehensive approach that addresses both physical and psychological aspects. The multifaceted nature of these conditions necessitates individualized treatment plans that can effectively alleviate symptoms and improve the quality of life for these individuals.
Physical therapy and exercise are critical components of managing motor disorders and associated pain in neurodivergent populations. Physical activities such as swimming, horseback riding, and martial arts can significantly improve motor skills, muscle tone, and overall physical coordination in children with ASD. These activities not only enhance physical fitness but also promote social skills and sensory integration.
Parents and caregivers should consult with healthcare providers to tailor these activities to their child's specific needs. Physical therapists can provide guidance on suitable exercises and activities that can be practiced at home to further support motor development and reduce muscle stiffness.
For individuals with hypertonia, pharmacological treatments can be crucial in managing muscle stiffness and improving mobility. Medications like Baclofen, Tizanidine, and Dantrolene are commonly used:
In severe cases where medications are not sufficient, surgical interventions might be considered. Intrathecal Baclofen pumps deliver Baclofen directly into the spinal fluid, allowing for higher concentrations of the medication at the site of action with fewer systemic side effects. Deep brain stimulation (DBS) involves the implantation of electrodes in specific brain areas to regulate abnormal signals and has shown promise in treating generalized dystonia. However, the outcomes can be variable and require thorough evaluation and monitoring.
Psychological therapies tailored to the unique needs of neurodivergent individuals are also beneficial in managing chronic pain and hypertonia. These interventions can help address the emotional and cognitive aspects of pain and motor dysfunctions, providing a holistic approach to treatment.
Educational support for clinicians is crucial to improve their understanding of the specific pain expressions and needs of neurodivergent individuals. Training healthcare providers in recognizing atypical pain behaviors and understanding the sensory sensitivities of individuals with ASD can lead to more effective and compassionate care. Providing resources and continuous education on the latest research and management strategies can empower clinicians to offer the best possible support.
Managing chronic pain and hypertonia in neurodivergent populations involves a multi-disciplinary approach that includes physical therapy, pharmacological treatments, and psychological interventions. Each strategy plays a vital role in addressing different aspects of these complex conditions, ultimately aiming to improve the overall well-being and quality of life for individuals with ASD and ADHD.
Chronic pain and hypertonia significantly impact the lives of neurodivergent individuals. Understanding the underlying mechanisms and developing tailored management strategies are essential for improving their quality of life. Future research should continue to explore the complex interactions between neurobiological dysfunctions, motor impairments, and pain perception in these populations to develop more effective interventions.
By addressing both the physical and psychological aspects of these conditions, healthcare providers can better support neurodivergent individuals in managing chronic pain and hypertonia, ultimately enhancing their overall well-being.
Bogdanova, O. V., Bogdanov, V. B., Pizano, A., Bouvard, M., Cazalets, J.-R., Mellen, N., & Amestoy, A. (2022). The current view on the paradox of pain in autism spectrum disorders. Frontiers in Psychiatry, 13. Link
Ibarra, M. (2020, March 4). Hypertonia and hypotonia: Overcoming motor disorders in autism - world stem cells clinic. World Stem Cells Clinic. Link
Jeoung, B. (2014). The relationship between attention deficit hyperactivity disorder and health-related physical fitness in university students. Journal of Exercise Rehabilitation, 10(6), 367–371 Link
Jordan, A., Parchment, A., Gauntlett-Gilbert, J., Jones, A., Donaghy, B., Wainwright, E., Connell, H., Walden, J., & Moore, D. J. (2024). Understanding the impacts of chronic pain on autistic adolescents and effective pain management: A reflexive thematic analysis adolescent–maternal dyadic study. Journal of Pediatric Psychology, 49(3), 185–194 Link
Joseph, C., Bailey-Sands, E., Simenson, R., Cameron, M., May, A., Hussein, N., Shin, M., & Evans, S. (2023). Rehabilitation management: Hypertonia. Current Problems in Pediatric and Adolescent Health Care, 53(1), 101349. Link
Maranan, K. (2020, June 3). 5 exercises for hypertonic muscle (high muscle tone). NAPA. Link
Mundal, I., Schei, J., Lydersen, S., Thomsen, P., Nøvik, T., & Kvitland, L. R. (2023). Prevalence of chronic and multisite pain in adolescents and young adults with ADHD: A comparative study between clinical and general population samples (the hunt study). European Child & Adolescent Psychiatry, 33(5), 1433–1442. Link
Paquet, A., Olliac, B., Bouvard, M.-P., Golse, B., & Vaivre-Douret, L. (2016). The semiology of motor disorders in autism spectrum disorders as highlighted from a standardized neuro-psychomotor assessment. Frontiers in Psychology, 7. Link
Stray, L., Kristensen, Ø., Lomeland, M., Skorstad, M., Stray, T., & Tønnessen, F. (2013). Motor regulation problems and pain in adults diagnosed with ADHD. Behavioral and Brain Functions, 9(1), 18. Link
Stray, L. T. (2015). Neuromuscular regulation problems in attention deficit hyperactivity disorder assessed by the motor function neurological assessment. Journal of Novel Physiotherapies, 5(2). Link
Zain, E., Sugimoto, A., Egawa, J., & Someya, T. (2023). Case report: Methylphenidate improved chronic pain in an adult patient with attention deficit hyperactivity disorder. Frontiers in Psychiatry, 14. Link