Somatosensory functioning and experienced pain in ADHD-families: a pilot study

Risk Factors for the Development of Multisite Pain in Children

OBJECTIVE

Chronic pain has economic costs on par with cardiovascular disease, diabetes, and cancer. Despite this impact on the health care system and increasing awareness of the relationship between pain and mortality, efforts to identify simple symptom-based risk factors for the development of pain, particularly in children, have fallen short. This is critically important as pain that manifests during childhood often persists into adulthood. To date, no longitudinal studies have examined symptoms in pain-free children that presage a new, multisite manifestation of pain in the future. We hypothesized that female sex, sleep problems, and heightened somatic symptoms complaints at baseline would be associated with the risk of developing new multisite pain 1 year later.

METHODS

Symptom assessments were completed by parents of youth (ages 9 to 10) enrolled in the Adolescent Brain Cognitive Development study. Multivariate logistic regression models focused on children who developed multisite pain 1 year later (n=331) and children who remained pain free (n=3335).

RESULTS

Female sex (odds ratio [OR]=1.35; 95% CI, 1.07, 1.71; P =0.01), elevated nonpainful somatic symptoms (OR=1.17; 95% CI, 1.06, 1.29; P <0.01), total sleep problems (OR=1.20; 95% CI, 1.07, 1.34; P <0.01), and attentional issues (OR=1.22; 95% CI, 1.10, 1.35; P <0.001) at baseline were associated with new multisite pain 1 year later. Baseline negative affect was not associated with new multisite pain.

DISCUSSION

Identifying symptom-based risk factors for multisite pain in children is critical for early prevention. Somatic awareness, sleep and attention problems represent actionable targets for early detection, treatment, and possible prevention of multisite pain in youth.

The effect of methylphenidate on pain perception thresholds in children with attention deficit hyperactivity disorder

BACKGROUND

Pain perception is important in children with attention deficit hyperactivity disorder (ADHD) since they are more likely to experience painful events due to increased accident rates. The aim of this study is to contribute to the literature concerning the relationship between ADHD diagnosis, methylphenidate (MPH) therapy, and pain thresholds, since findings regarding the change in pain perception in children with ADHD are scarce and inconsistent.

METHODS

Children aged 8-13 years constituted both the ADHD group (n = 82) and the healthy controls (n = 41). The ADHD group was divided into two subgroups, ADHD without MPH (not treated pharmacologically) and ADHD with MPH (treated pharmacologically for at least three-months). The Conners' Parent Rating Scale-Revised: Short Form was employed to assess ADHD, a visual analog scale was applied to evaluate chronic pain severity, and a manual pressure algometer was used to assess pain thresholds.

RESULT

Children with ADHD had lower pain thresholds than the healthy controls (P < 0.05). However, lower regional pain thresholds were observed in the ADHD group without MPH compared to both the healthy control and ADHD with MPH groups. Although pain thresholds in the ADHD with MPH group were regionally lower than in the healthy controls, low pain thresholds were found in fewer regions compared to the ADHD without MPH group.

CONCLUSIONS

Children with ADHD are more sensitive to pain sensation, and MPH may help normalize these individuals' pain experiences by raising pain thresholds. Families and clinicians must be aware of situations that may cause pain in children with ADHD. In addition, these children's low threshold for pain may lead them to experience it more intensely.

Interictal Cognitive Performance in Children and Adolescents With Primary Headache: A Narrative Review

Primary headache is a very common and disabling disease. The burden of pain and recurrent attacks may lead to a poor quality of life, anxiety and depression. An increased risk of low functioning and curricular performances in young patients with primary headache has been described. The mechanisms underlying the relationship between migraine and poor school achievement may be various and could be a reflection of weak cognitive skills. Data concerning the cognitive functioning in the free pain interval in pediatric age are under-investigated and results are far from conclusive. The present review article suggests that, though considered a benign disease, pediatric migraine may be associated to altered neuropsychological functioning in the interictal phase. Although children and adolescents with migraine generally have a normal intelligence, they may show a not homogeneous cognitive profile, characterized by possible difficulties in verbal skills, in particular comprehension abilities. Pediatric primary headache may present altered neuropsychological functioning involving attentional resources, processing speed and memory, particularly verbal memory. Given the impact that this disease can have on school performance and the tendency to persist from childhood to adulthood, a cognitive screening in young patients affected by primary headache is pivotal. Additional neuropsychological research using more homogenous methods is needed.

Neuroinflammation as a possible link between attention-deficit/hyperactivity disorder (ADHD) and pain

Attention-deficit/hyperactivity disorder (ADHD) and pathological pain are two complex syndromes of multifactorial origin. Despite their prevalence and broad impacts, these conditions are seldom recognized and managed simultaneously. The co-existence of neuropsychiatric conditions (such as ADHD) and altered pain perception and chronic pain has been noted in children, and the comorbidity of ADHD and chronic pain is well documented in adults. Pathophysiological studies have suggested dysfunction of the dopaminergic system as a common neurochemical basis for comorbid ADHD and pain. Considerable evidence supports the role of neuroinflammation in the pathophysiology of both. We suggest that central neuroinflammation underlies altered pain perception and pain sensitization in persons with ADHD. Based on our hypothesis, targeting neuroinflammation may serve as a potential new therapeutic intervention to treat ADHD and comorbid pain in children and adolescents and a preventive strategy for the development of chronic pain in adults with ADHD.

Speech motor control and orofacial point pressure sensation in adults with ADHD

Attention-Deficit Hyperactivity Disorder (ADHD) is a predominant neurobehavioral disorder of childhood with motor and sensory symptoms often persisting into adulthood. Motor control theories highlight the importance of the bidirectional relationship between sensation and movement for maintaining skilled behaviors like speech. The impact of ADHD on speech in adults has not been well established. The purpose of this study is to assess group differences in quantitative speech and oral somatosensory measures in adults with and without ADHD and to describe the relationship between ADHD symptomology and speech production. A total of 50 adults (18-26 years) were recruited and divided in two groups based on diagnosis: those with (n = 28) and those without (n = 22) ADHD. All participants provided a speech sample to measure articulatory accuracy and speech rate and completed quantitative point-pressure testing using tactile detection and discrimination on bilateral sites on the lower lip and lateral edge of the tongue tip. Independent t-tests corrected for multiple comparisons identified significant group differences using FDR corrected q values in speech production for correct syllables per second and overall speech rate (q<.05). Additionally, there were significant group differences (q<.05) for detection and discrimination threshold estimates at one testing location. Bivariate correlations identified a relationship between several speech measures and self-reported ADHD symptoms such that as symptom severity increased, speech accuracy for correct syllables per second decreased. Young adults with ADHD have subtle differences in speech production compared to non-ADHD control participants. Speech scientists might consider screening for ADHD when collecting normative data samples.

Behavioural and neural markers of tactile sensory processing in infants at elevated likelihood of autism spectrum disorder and/or attention deficit hyperactivity disorder

Backgrounds

Atypicalities in tactile processing are reported in autism spectrum disorder (ASD) and attention deficit hyperactivity disorder (ADHD) but it remains unknown if they precede and associate with the traits of these disorders emerging in childhood. We investigated behavioural and neural markers of tactile sensory processing in infants at elevated likelihood of ASD and/or ADHD compared to infants at typical likelihood of the disorders. Further, we assessed the specificity of associations between infant markers and later ASD or ADHD traits.

Methods

Ninety-one 10-month-old infants participated in the study (n = 44 infants at elevated likelihood of ASD; n = 20 infants at elevated likelihood of ADHD; n = 9 infants at elevated likelihood of ASD and ADHD; n = 18 infants at typical likelihood of the disorders). Behavioural and EEG responses to pairs of tactile stimuli were experimentally recorded and concurrent parental reports of tactile responsiveness were collected. ASD and ADHD traits were measured at 24 months through standardized assessment (ADOS-2) and parental report (ECBQ), respectively.

Results

There was no effect of infants’ likelihood status on behavioural markers of tactile sensory processing. Conversely, increased ASD likelihood associated with reduced neural repetition suppression to tactile input. Reduced neural repetition suppression at 10 months significantly predicted ASD (but not ADHD) traits at 24 months across the entire sample. Elevated tactile sensory seeking at 10 months moderated the relationship between early reduced neural repetition suppression and later ASD traits.

Conclusions

Reduced tactile neural repetition suppression is an early marker of later ASD traits in infants at elevated likelihood of ASD or ADHD, suggesting that a common pathway to later ASD traits exists despite different familial backgrounds. Elevated tactile sensory seeking may act as a protective factor, mitigating the relationship between early tactile neural repetition suppression and later ASD traits.

Impulsivity prevalence in migraine patients without and with medication overuse

BACKGROUND

Migraine is one of the most common disorders in neurological clinical practice and is part of the group of primary headaches. It often affects individuals in the age group of 25-55 years, when people are at their peak of economic productivity. Many patients ultimately overuse analgesics. Overuse is defined by the use of analgesics for at least 15 times a month - within a minimal three-month period. Impulsivity and migraine cause losses in the lives of individuals suffering from them, as they can compromise these individuals' social, emotional, and professional spheres. Regarding the professional sphere, it results in economic losses compared with the overall population.

OBJECTIVE

To investigate the presence of impulsive behavior in patients with migraine and with medication-overuse migraine.

METHODS

Cross-sectional study on 210 female and male patients; 140 were diagnosed with migraine according to criteria of the International Classification of Headache Disorders and were subdivided into two groups (70 patients each). One of these groups was composed of medication-overuse patients; the control group was composed of non-migraine patients (70 patients). All patients were evaluated with the Barratt Impulsivity Scale (BIS-11).

RESULTS

The group of migraine patients accounted for the highest impulsivity level, followed by the control group and, finally, by the medication-overuse group. However, these differences did not attain statistical significance.

CONCLUSIONS

It was not possible to establish a clear connection between migraine and impulsive behavior. Association was higher among migraineurs without medication overuse.

Childhood and adult attention deficit hyperactivity disorder symptoms in fibromyalgia: associations with depression, anxiety and disease impact

Objective: The first aim of this study was to determine the prevalence of childhood and current attention deficit hyperactivity disorder (ADHD) symptoms in patients with fibromyalgia. The second aim is to assess the role of depression and anxiety on the relationship between childhood and adult ADHD symptoms with disease impact in this population.Methods: Sixty-four patients with fibromyalgia were compared to matched 58 healthy controls. All participants completed the Wender Utah Rating Scale (WURS), Adult ADHD Self-Report Scale (ASRS), Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI) and Fibromyalgia Impact Questionnaire (FIQ).Results: Patients with fibromyalgia had significantly higher mean scores of depression (BDI), anxiety (BAI), childhood ADHD symptoms (WURS) and adult ADHD symptoms (ASRS total, ASRS hyperactivity/impulsivity subscale and ASRS attention deficit subscale) than the control group. Fibromyalgia impact (FIQ) was significantly correlated with depression (BDI; r = 0.57, p < .001), anxiety (BAI; r = 0.56, p < .001) and childhood ADHD symptoms (WURS; r = 0.41, p < .001) in fibromyalgia group. There was no significant correlation between fibromyalgia impact (FIQ) and adult ADHD symptoms (ASRS total or sub-scale scores). Hierarchical multiple regression indicated that childhood ADHD symptoms (WURS), anxiety (BAI) and depression (BDI) predicted fibromyalgia impact. Both anxiety (BAI) and depression (BDI) mediated the relationship between childhood ADHD symptoms (WURS) and fibromyalgia impact (FIQ).Conclusion: Childhood ADHD symptoms may be a contributory factor to poorer functioning in the patients with fibromyalgia. The relationship was more pronounced in the presence of depression and anxiety symptoms. Evaluation of childhood and adult ADHD symptoms in patients with fibromyalgia is important for recognition and treatment of ADHD comorbidity and also for attenuating the severity of the disease.

ADHD Is Comorbid to Migraine in Childhood: A Population-Based Study

Objective: Recurrent headaches and ADHD are prevalent in the pediatric population. Herein, we assess if ADHD is comorbid to headaches overall, to headache subtypes (e.g., migraine), and to headache frequency. Method: Informed consent and analyzable data were obtained for 5,671 children aged 5 to 12 years (65.9% of the target sample). Parents and teachers were interviewed using validated questionnaires based on the Diagnostic and Statistical Manual of Mental Disorders (5th ed.; DSM-5). Relative risks were modeled using univariate and multivariate analyses. Results: As contrasted to nonheadache controls, the prevalence of ADHD was significantly higher in children with migraine (p < .001) but not in those with tension-type headaches. In children with migraine, risk of ADHD increased as a function of headache frequency (p < .05). Conclusion: Migraine and frequent migraine are comorbid to ADHD. Future studies should focus on the impact of the association on the burden to the children and their families.

Tactile Discrimination, Praxis and Cognitive Impulsivity in ADHD Children: A Cross-Sectional Study

Background: The study of attention deficit hyperactivity disorder (ADHD) has traditionally focused on deficit of inhibitory control and cognitive impulsivity. However, the pathophysiology of ADHD has also been associated with the somatosensory cortex. The aim of this study was to explore if there were differences in tactile discrimination and praxis between neurotypical and ADHD children and whether these differences could be explained by cognitive impulsivity. Methods: A cross-sectional study was conducted. The sample comprised 74 children aged 7 to 11 years divided in two groups: 43 with neurotypical development, 31 with ADHD. To assess tactile discrimination, the finger localization and the graphestesia tests were used. Praxis was assessed with the Kaufman Assesment Battery for Children (K-ABC) hand movement subtest, the action program and the Zoo Map subtests of the Behavioral Assessment of Dysexecutive Syndrome, and the complex figure of Rey–Osterrieth test (ROCF). Cognitive impulsivity was assessed using the Magallanes Computerized Impulsivity Scale test (EMIC). Results: Children with ADHD showed greater cognitive impulsivity (p = 0.038) and scored lower in Zoo Map (p = 0.023) and hand-movement subtests (p = 0.002), and in ROCF test (p = 0.004). Differences in praxis skills still remained after controlling by gender and cognitive impulsivity. Conclusion: Praxis deficit might have repercussions not only on the characterization of ADHD but also on its treatment.

Sensory Function and Chronic Pain in Multiple Sclerosis

Objective

To examine whether hypoesthesia and chronic pain are related in patients with MS.

Methods

Sixty-seven MS patients with pain and 80 persons without MS were included. Sensory functioning was tested by bedside neurological examination. Touch, joint position (dorsal column-medial lemniscus pathway), temperature sense, and pain (spinothalamic tract) were tested. Pain intensity was measured by the Colored Analogue Scale (CAS Intensity) and the Faces Pain Scale (FPS); pain affect was also measured by CAS Affect and Number of Words Chosen-Affective (NWC-A). Mood was assessed with the SCL-90 anxiety and depression subscales and the Beck Depression Inventory (BDI).

Results

A significant negative relationship was found between pain intensity and the function of the dorsal column-medial lemniscal pathway, but not with the spinothalamic tract.

Conclusion

In addition to the already known relation between hyperesthesia and pain, hypoesthesia for touch and joint position also seems to be related to chronic pain in MS patients.

A Case of Congenital Insensitivity to Pain With Anhidrosis Comorbid With Attention Deficit Hyperactivity Disorder: Clinical Implications for Pathophysiology and Treatment

Congenital insensitivity to pain with anhidrosis (CIPA) is a rare autosomal recessive genetic disorder caused by a mutation in the neurotrophic tyrosine kinase receptor (NTRK1) gene. CIPA is accompanied by abnormal catecholamine metabolism and decreased blood concentration of dopamine and norepinephrine. Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder of heterogeneous etiology and presentation, and recent reports have suggested a pathophysiological role of neurotrophins in ADHD. Furthermore, dopamine and norepinephrine are known to play major roles in the pathophysiology of ADHD, and the imbalance of monoaminergic and cholinergic systems as an underlying cause of ADHD has recently been studied. Here, we report the case of an 11-year-old boy with CIPA and comorbid ADHD. Our observations have important clinical implications for patients with CIPA. Because of deficiencies in self-control, proper management of these patients necessitates a highly structured and monitored environment, made dually important by possible comorbidity of ADHD.

Sensory processing difficulties in school-age children born very preterm: An exploratory study

BACKGROUND

Very preterm birth has a detrimental impact on the developing brain, including widespread white matter brain abnormalities that threaten efficient sensory processing. Yet, sensory processing difficulties in very preterm children are scarcely studied, especially at school age.

AIMS

To investigate somatosensory registration, multisensory integration and sensory modulation.

PARTICIPANTS

57 very preterm school-age children (mean age=9.2years) were compared to 56 gender and age matched full-term children.

METHODS

Group differences on somatosensory registration tasks (Registration of Light Touch, Sensory Discrimination of Touch, Position Sense, Graphestesia), a computerized multisensory integration task, and the parent-reported Sensory Profile were investigated using t-tests and Mann-Whitney U tests.

RESULTS

In comparison to full-term children, very preterm children are less accurate on somatosensory registration tasks, including Registration of Light Touch (d=0.34), Position Sense (d=0.31) and Graphestesia (d=0.42) and show more sensory modulation difficulties (d=0.41), including both behavioral hyporesponsivity (d=0.52) and hyperresponsivity (d=0.56) to sensory stimuli. Tactile discrimination and multisensory integration efficiency were not affected in very preterm children. Aspects of sensory processing were only modestly related.

CONCLUSION

Very preterm children show sensory processing difficulties regarding somatosensory registration and sensory modulation, and preserved multisensory (audio-visual) integration. Follow-up care for very preterm children should involve screening of sensory processing difficulties at least up to school age.

A scoping review on the study of siblings in pediatric pain

Background: Sibling relationships are longstanding across an individual’s life and are influential in children’s development. The study of siblings in pediatric pain is, although in early stages, a growing field.

Aims: This scoping review sought to summarize and map the type of research available examining siblings and pediatric pain to identify gaps and directions for future research.

Methods: Studies were identified based on a search of PubMed, CINAHL, PsycInfo, Embase, and Web of Science (up to November 2016). We extracted data about study methods, the sample, outcome assessment, and the influence/relationships investigated.

Results: Thirty-five studies were included. Most studies used quantitative methods (n = 28), and participants typically included children (i.e., aged 6–12; n = 24) and adolescents (i.e., aged 13–18; n = 18). The majority of studies examined siblings in the context of chronic and disease-related pain (n = 30). Though quantitative studies primarily focused on the genetic influence of pain conditions (n = 18), qualitative and mixed-methods studies typically focused on exploring the impact of siblings with and without pain on one another (n = 2) and the impact of pain on the broader dyadic relationship/functioning (n = 4).

Conclusions: Sibling research in pediatric pain has been primarily focused on the biological/physical components of pain, using quantitative approaches. Conducting more studies using qualitative or mixed-methods designs, incorporating multiple assessment measures (e.g., observational, self-report) and multiple perspectives (e.g., siblings, health professionals), may provide an opportunity to gain richer and more comprehensive information regarding the experience of siblings.

Perception in attention deficit hyperactivity disorder

A large body of research demonstrated that individuals with attention deficit hyperactivity disorder (ADHD) suffer from various neuropsychological deficits. In contrast, less is known and only divergent evidence exists on perceptual functions of individuals with ADHD. This is problematic as neuropsychological and perceptual functions are closely interrelated and are often difficult to disentangle in behavioral assessments. This study presents the conduct and results of a systematic literature review on perceptual functions in children and adults with ADHD. This review considers studies using psychophysical methods (objective measurements) and self- and informant reports (subjective measurements). Results indicate that individuals with ADHD have altered perceptual functions in various domains as compared to typically developing individuals. Increased perceptual functions in individuals with ADHD were found with regard to olfactory detection thresholds, whereas reduced perceptual functions were evident for aspects of visual and speech perception. Moreover, individuals with ADHD were found to experience discomfort to sensory stimuli at a lower level than typically developing individuals. Alterations of perceptual functions in individuals with ADHD were shown to be moderated by various factors, such as pharmacological treatment, cognitive functions, and symptom severity. We conclude by giving implications for daily life functioning and clinical practice.

Sensory modulation in preterm children: Theoretical perspective and systematic review

BACKGROUND

Neurodevelopmental sequelae in preterm born children are generally considered to result from cerebral white matter damage and noxious effects of environmental factors in the neonatal intensive care unit (NICU). Cerebral white matter damage is associated with sensory processing problems in terms of registration, integration and modulation. However, research into sensory processing problems and, in particular, sensory modulation problems, is scarce in preterm children.

AIM

This review aims to integrate available evidence on sensory modulation problems in preterm infants and children (<37 weeks of gestation) and their association with neurocognitive and behavioral problems.

METHOD

Relevant studies were extracted from PubMed, EMBASE.com and PsycINFO following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Selection criteria included assessment of sensory modulation in preterm born children (<37 weeks of gestation) or with prematurity as a risk factor.

RESULTS

Eighteen studies were included. Results of this review support the presence of sensory modulation problems in preterm children. Although prematurity may distort various aspects of sensory modulation, the nature and severity of sensory modulation problems differ widely between studies.

CONCLUSIONS

Sensory modulation problems may play a key role in understanding neurocognitive and behavioral sequelae in preterm children. Some support is found for a dose-response relationship between both white matter brain injury and length of NICU stay and sensory modulation problems.

Assessment of Sensory Processing Characteristics in Children between 3 and 11 Years Old: A Systematic Review

The assessment of sensory perception, discrimination, integration, modulation, praxis, and other motor skills, such as posture, balance, and bilateral motor coordination, is necessary to identify the sensory and motor factors influencing the development of personal autonomy. The aim of this work is to study the assessment tools currently available for identifying different patterns of sensory processing. There are 15 tests available that have psychometric properties, primarily for the US population. Nine of them apply to children in preschool and up to grade 12. The assessment of sensory processing is a process that includes the use of standardized tests, administration of caregiver questionnaires, and clinical observations. The review of different studies using PRISMA criteria or Osteba Critical Appraisal Cards reveals that the most commonly used tools are the Sensory Integration and Praxis Test, the Sensory Processing Measure, and the Sensory Profile.

ADHD symptoms and pain among adults in England

Prior research has produced conflicting findings on the association between attention-deficit/hyperactivity disorder (ADHD) and pain, while studies among community-dwelling adults are lacking. This study examined the association between ADHD symptoms and pain in the general adult population, and the extent to which this association is influenced by comorbid common mental disorders (CMDs). Data came from the 2007 Adult Psychiatric Morbidity Survey which included a representative sample of the English adult household population aged ≥16 years (N=7403). The Adult ADHD Self-Report Scale (ASRS) Screener was used to obtain information on ADHD symptoms, while pain was assessed by the degree to which it interfered with work activity in the previous month. The Clinical Interview Schedule Revised (CIS-R) was used to evaluate six categories of CMDs. In a binary logistic regression analysis adjusted for socio-demographic factors and physical health conditions, an ADHD symptom score ≥14 was strongly associated with extreme pain (odds ratio [OR]: 3.15, 95% confidence interval [CI]: 2.09-4.74). The OR was attenuated greatly after further adjustment for CMDs (OR: 1.64, 95% CI: 1.05-2.58) but remained statistically significant. Adults with ADHD symptoms have higher odds for experiencing pain. CMDs are influential in this association but do not fully explain it.

Reduced pain perception in children and adolescents with ADHD is normalized by methylphenidate

BACKGROUND

The present study examined pain perception in children and adolescents with ADHD and the interaction between pain perception and the administration of methylphenidate (MPH) in order to generate hypotheses for further research that will help to clarify the association between ADHD diagnosis, MPH treatment and pain perception.

METHODS

We included 260 children and adolescents of the "German Health Interview and Examination Survey for Children and Adolescents" (KiGGS) and analyzed parent's assessments of children's pain distribution and pain perception, as well as the influence of MPH administration on pain perception in affected children and adolescents.

RESULTS

Pain perception was associated with ADHD and MPH administration, indicating that children and adolescents suffering from ADHD without MPH treatment were reported to have lower pain perception compared to both, healthy controls (HC) and ADHD patients medicated with MPH.

CONCLUSION

We suggest that reduced pain perception in children and adolescents with ADHD not medicated with MPH may lead to higher risk tolerance by misjudgments of dangerous situations, expanding the importance of MPH administration in affected children and adolescents.

Quantitative sensory testing of temperature, pain, and touch in adults with Down syndrome

The spinothalamic pathway mediates sensations of temperature, pain, and touch. These functions seem impaired in children with Down syndrome (DS), but have not been extensively examined in adults. The objective of the present study was to compare the spinothalamic-mediated sensory functions between adults with DS and adults from the general population and to examine in the DS group the relationship between the sensory functions and level of intellectual functioning. Quantitative sensory testing (QST) was performed in 188 adults with DS (mean age 37.5 years) and 142 age-matched control participants (median age 40.5 years). Temperature, pain, and touch were evaluated with tests for cold-warm discrimination, sharp-dull discrimination (pinprick), and tactile threshold, respectively. Level of intellectual functioning was estimated with the Social Functioning Scale for Intellectual Disability (intellectual disability level) and the Wechsler Preschool and Primary Scale of Intelligence--Revised (intelligence level). Overall, the difference in spinothalamic-mediated sensory functions between the DS and control groups was not statistically significant. However, DS participants with a lower intelligence level had a statistically significant lower performance on the sharp-dull discrimination test than DS participants with higher intelligence level (adjusted p=.006) and control participants (adjusted p=.017). It was concluded that intellectual functioning level is an important factor to take into account for the assessment of spinothalamic-mediated sensory functioning in adults with DS: a lower level could coincide with impaired sensory functioning, but could also hamper QST assessment.

Pain Sensitivity in Adolescent Males with Attention-Deficit/Hyperactivity Disorder: Testing for Associations with Conduct Disorder and Callous and Unemotional Traits

Background

Reduced processing and experience of aversive emotional cues is a common component of theories on the development and persistence of aggression and antisocial behaviour. Yet physical pain, arguably the most basic aversive cue, has attracted comparatively little attention.

Methods

This study measured pain sensitivity and physiological response to painful stimuli (skin conductance level, SCL) in adolescent boys with Attention-Deficit/Hyperactivity Disorder (ADHD; n = 183), who are at high risk for antisocial behaviour. We compared boys with ADHD with and without a comorbid diagnosis of Conduct Disorder (CD) on pain sensitivity, and examined patterns of association between pain measures, on the one hand, and problem severity and callous and unemotional (CU) traits, on the other.

Results

Boys with comorbid CD exhibited a higher pain threshold and tolerance than boys with ADHD alone, but the groups did not differ in physiology at the time the pain threshold and tolerance were reported. Regression analyses showed that ADHD problem severity positively predicted pain sensitivity, whereas levels of CU traits negatively predicted pain sensitivity.

Conclusions

These findings on physical pain processing extend evidence of impairments in aversive cue processing among those at risk of antisocial behaviour. The study highlights the importance of considering comorbidity and heterogeneity of disorders when developing interventions. The current findings could be used to identify subgroups within those with ADHD who might be less responsive to interventions that use corrective feedback to obtain behaviour change.

Pain in dementia: prevalence and associated factors: protocol of a multidisciplinary study

Background

Pain is a common problem in people with dementia, however the exact prevalence of pain in dementia subtypes, e.g. Alzheimer’s Disease (AD), Vascular Dementia (VaD), Frontotemporal Dementia (FTD) and dementia with Lewy Bodies (DLB), is unknown, as is the relation between pain and the different subtypes of dementia. In this study, the prevalence of pain in people with dementia will be investigated per dementia subtype and the relationship between the various subtypes of dementia and the presence of specific types of pain (i.e. musculoskeletal pain, neuropathic pain and orofacial pain) will be examined. Secondly, associations between various types of pain, cognitive functioning, neuropsychiatric symptoms and quality of life in people with dementia will be examined. A third purpose is to study the value of the assessment of autonomic responses in assessing pain in people with dementia. Finally, the effect of feedback to the attending physician on the presence of pain, based on examination by investigators with backgrounds in neuropsychology, geriatric dentistry and elderly care medicine, will be evaluated.

Methods/Design

A cross-sectional, partially longitudinal observational study in 400 participants with dementia, aged 60 years and older. Participants will be recruited from an outpatient memory clinic and dementia special care units. All participants will be examined by an elderly care medicine trainee, a dentist with experience in geriatric dentistry, and a neuropsychologist. The primary outcome is presence of pain. Secondary outcomes will include oral health, autonomic responses to pain stimulus, vital sensibility and gnostic sensibility, musculoskeletal examination, cognitive functioning, neuropsychiatric symptoms, and quality of life.

Discussion

This study will help to enhance our knowledge regarding the prevalence of different types of pain in different dementia subtypes i.e. AD, VaD, FTD and DLB. This study also aims to contribute to a better understanding of oral health status in people with dementia, the use of autonomic responses in the assessment of pain in people with dementia and the relationships between pain and cognitive symptoms, neuropsychiatric symptoms and quality of life in people with various dementia subtypes and in different stages of the disease.

Alterations in pain response are partially reversed by methylphenidate (Ritalin) in adults with attention deficit hyperactivity disorder (ADHD)

BACKGROUND

Attention deficit hyperactivity disorder (ADHD) is characterized by dysregulation of sensory processing and neurobiology of dopamine. Although cumulative evidence suggests that dopamine is involved in pain processing, pain perception in ADHD subjects and the effect of dopamine agonists such as methylphenidate (MP, Ritalin) on it have rarely been studied.

AIMS

The aims of this study were to (1) psychophysically assess sensitivity to pain in ADHD subjects as compared to controls and (2) examine the effects of MP on pain response in ADHD subjects.

METHODS

Thirty subjects with ADHD and 30 age- and gender-matched controls participated in a preliminary trial. Pain threshold, intensity, and tolerance in response to cold pain stimulation were measured for both groups (ADHD with no treatment). In addition, the ADHD group was reassessed following a single dose of MP treatment.

RESULTS

The ADHD subjects "without MP" in comparison with controls displayed significantly shorter cold pain threshold (2.8 ± 2.1 vs. 5.8 ± 2.5 seconds, respectively, P < 0.001) and cold tolerance (21.8 ± 22.3 vs. 62.8 ± 59.8 seconds, respectively P < 0.001). No differences in pain intensities between the groups were found. Following MP treatment, both cold threshold and tolerance in the ADHD subjects increased significantly compared to those with no treatment (3.6 ± 2.5 seconds, P = 0.011, and 46.4 ± 53.3 seconds, P < 0.001, respectively).

CONCLUSIONS

These results suggest that adults with ADHD are more sensitive to pain compared with controls and that MP may exert antinociceptive properties in these subjects. Randomized, controlled trials are warranted to verify these findings.

A comparison of the oxygen cost and physiological responses to running in children with and without Developmental Coordination Disorder

The aim of this study was to compare the oxygen cost of running in boys with and without Developmental Coordination Disorder (DCD). Fourteen boys with DCD (9.1 ± 1.4 yr) and 16 typically developing (TD) controls (9.4 ± 1.3 yr) were tested on two separate occasions at least a week apart. On the first visit, motor proficiency, body composition and maximal aerobic capacity were established. On the second visit, oxygen consumption was determined via indirect calorimetry while participants ran at three submaximal speeds (7.2 km/h, 8.0 km/h and 8.8 km/h) on a motorised treadmill for 4 min each. Additional physiological responses such as blood lactate, respiratory exchange ratio (RER), heart rate, salivary alpha amylase and pain threshold were monitored at baseline and after each submaximal effort. Although there were no differences in the oxygen cost of running at all three speeds, the boys with DCD had higher blood lactate concentration (7.2 km/h, p=0.05; 8.0 km/h p=0.019), heart rate (p ≤ 0.001), RER (8.0 km/h, p=0.019; 8.8 km/h, p=0.001), salivary alpha amylase (8.0 km/h, p=0.023; 8.8 km/h, p=0.020) and a lower pain threshold (p<0.01). The higher overall metabolic cost of running in boys with DCD as indicated by the higher RER, heart rate and blood lactate concentrations, together with the higher levels of sympathoadrenal medullary activity and sensitivity to pain, may be deterring factors for participation in physical activity in this population.

Postural control among children with and without attention deficit hyperactivity disorder in single and dual conditions

Given the known deficits in attention in attention deficit hyperactivity disorder (ADHD) and the evidence suggesting that postural control requires attention, this study aimed to investigate the mechanisms of postural control of children with and without ADHD in single-(ST) and dual-task (DT) conditions. Postural sway and stabilogram diffusion analysis (SDA) were performed on the Center of Pressure trajectories on 24 ADHD children and 17 age-gender-matched healthy controls. The subjects were instructed to stand as stable as possible on a force platform in two task conditions: (1) single task (ST) and (2) dual task (DT)-an auditory-memory attention-demanding cognitive task. During ST and DT conditions, the ADHD children showed significantly greater ML-sway, short- and long-term effective diffusion coefficients, and critical displacement of SDA compared with controls. The effects of DT were somewhat unexpected; the control group indicated a significant decrease in ML-sway, AP-sway, sway area, and critical displacement of SDA; the ADHD group showed a significant decrease in ML-sway range and critical displacement. It is concluded that a greater sway displacement before closed-loop mechanisms is called into play in ADHD children. The DT enhanced balance control by reinforcing balance automaticity and minimizing sway in both healthy and ADHD children.

Altered cortical morphology in sensorimotor processing regions in adolescents and adults with attention-deficit/hyperactivity disorder

Attention-deficit/hyperactivity disorder (ADHD) is a neurodevelopmental disorder that is common in children and frequently persists into adulthood. While ADHD is characterized by developmentally inappropriate, persistent and impairing levels of inattention, impulsiveness and hyperactivity, it is also associated with sensorimotor deficits and altered neural processing of somatosensory stimuli, as well as with executive function deficits. The latter are associated with thinning of frontal lobe structures in ADHD; however, few structural neuroimaging studies have focused on changes in brain morphology in sensorimotor regions in this population. Moreover, little is known about morphological changes that occur in these regions throughout the developmental trajectory into adulthood. In this preliminary cross-sectional study, we examined cortical thickness with a focus on brain regions involved in sensorimotor processing in adolescents and adults with ADHD compared to neurotypical cohorts. Compared to controls, adolescents with ADHD showed significant increased cortical thickness in the pre-supplementary motor area (SMA) and adults with ADHD showed increased thickness in the primary somatosensory cortex (SI). Based on these differences, we collated the data from the adolescents and adults and examined possible age×group interaction effects on cortical thickness. A significant interaction effect was found in SI where healthy participants showed decreased thickness in this region at older ages, whereas the ADHD cohort showed little change. Results suggest that sensorimotor brain regions are altered in ADHD and these changes may not dissipate in adolescence, but rather persist into adulthood.

Somatosensory processing in neurodevelopmental disorders

The purpose of this article is to review the role of somatosensory perception in typical development, its aberration in a range of neurodevelopmental disorders, and the potential relations between tactile processing abnormalities and central features of each disorder such as motor, communication, and social development. Neurodevelopmental disorders that represent a range of symptoms and etiologies, and for which multiple peer-reviewed articles on somatosensory differences have been published, were chosen to include in the review. Relevant studies in animal models, as well as conditions of early sensory deprivation, are also included. Somatosensory processing plays an important, yet often overlooked, role in typical development and is aberrant in various neurodevelopmental disorders. This is demonstrated in studies of behavior, sensory thresholds, neuroanatomy, and neurophysiology in samples of children with Fragile X syndrome, autism spectrum disorders (ASD), attention deficit hyperactivity disorder (ADHD), and cerebral palsy (CP). Impaired somatosensory processing is found in a range of neurodevelopmental disorders and is associated with deficits in communication, motor ability, and social skills in these disorders. Given the central role of touch in early development, both experimental and clinical approaches should take into consideration the role of somatosensory processing in the etiology and treatment of neurodevelopmental disorders.

Cortical dynamics of selective attention to somatosensory events

Recent studies have shown evidence of somatosensory deficits in individuals with attentional difficulties yet relatively little is known about the role of attention in the processing of somatosensory input. Neuromagnetic imaging studies have shown that rhythmic oscillations within the human somatosensory cortex are strongly modulated by somatosensory stimulation and may reflect the normal processing of such stimuli. However, few studies have examined how attention influences these cortical oscillations. We examined attentional effects on human somatosensory oscillations during median nerve stimulation by conducting time-frequency analyses of neuromagnetic recordings in healthy adults. We found that selective attention modulated somatosensory oscillations in the alpha, beta, and gamma bands that were both phase-locked and non-phase-locked to the stimulus. In the primary somatosensory cortex (SI), directing the subject's attention toward the somatosensory stimulus resulted in increased gamma band power (30-55 Hz) that was phase-locked to stimulus onset. Directed attention also produced an initial suppression (desynchrony) followed by enhancement (synchrony) of beta band power (13-25 Hz) that was not phase-locked to the stimulus. In the secondary somatosensory cortex (SII), directing attention towards the stimulus increased phase-locked alpha (7-9 Hz) power approximately 30 ms after onset of phase-locked gamma in SI, followed by a non-phase-locked increase in alpha power. We suggest that earlier phase-locked oscillatory power may reflect the relay of input from SI to SII, whereas later non-phase-locked rhythms reflect stimulus-induced oscillations that are modulated by selective attention and may thus reflect enhanced processing of the stimulus underlying the perception of somatosensory events.