Pictorial Review of Cranial Nerve Denervation in the Head and Neck.

Of the twelve cranial nerves, nine supply motor innervation to the muscles of the head and neck. Loss of this motor nerve supply, or denervation, follows a series of predictable chronologic changes in the affected muscles. Although the length of time between each change is markedly variable, denervation is typically classified into three distinct time points: (a) acute, (b) subacute, and (c) chronic. These muscle changes produce characteristic findings on images, with contrast-enhanced MRI being the preferred modality for assessment. Imaging allows radiologists to not only identify denervation but also evaluate the extent of denervation and localize the potential site of insult. However, these findings may be easily mistaken for other diseases with similar manifestations, such as neoplasm, infection, and inflammatory conditions. As such, it is fundamental for radiologists to be familiar with cranial nerve anatomy and denervation patterns so that they can avoid these potential pitfalls and focus their imaging search on the pathway of the affected nerve. In this article, the anatomy and muscles innervated by motor cranial nerves in the head and neck, denervation, and the associated expected imaging patterns are reviewed, and examples of potential pitfalls and denervation mimics are provided. ©RSNA, 2024.

Nerve entry points in the mimic musculature of the horse head.

Facial expressions are important in pain recognition in horses, but current observation-based pain scales remain subjective. A promising technique to quantitatively measure subtle changes in expression patterns, including changes invisible to the human eye, is surface electromyography (sEMG). To achieve high-quality and reliable sEMG signals, unilateral placement of bipolar electrodes is required in relation to the motor endplates (MEP). We aimed to localize the nerve entry points (NEPs; where the nerve branch first pierced the muscle belly) and the direction of the terminal nerve endings to estimate MEP locations of the innervating nerves in five equine facial muscles involved in pain expression. Three cadaveric Dutch Warmblood horse heads were dissected to identify the NEPs in the musculi caninus, levator anguli oculi medialis, nasolabialis, masseter and zygomaticus. These points were marked with pins and measured in relation to a reference line between two anatomical landmarks near the origin and insertion of the respective muscle. Relative distances were calculated from the most caudally situated landmark. NEPs were located at 33%-38% (caninus), 69%-86% (levator anguli oculi medialis) and 0%-18% (zygomaticus) from the caudal landmark. The nasolabialis showed two innervations zones. Its NEPs were located at 47%-72% (dorsal muscle branch) and 52%-91% (ventral branch). All terminal nerve endings were found to run in rostral direction. The masseter showed numerous NEPs diffusely spread within the muscle belly. Therefore, calculation of relative positions was not performed. These results could form the basis for feasibility studies and standardization of bipolar electrode positioning in vivo to measure facial muscle activity patterns in horses.

Hush, little baby: The role of C-tactile afferents in babywearing infants with neonatal opioid withdrawal.

Social touch through infant holding, skin-to-skin contact, and infant carrying (babywearing) decreases infant distress and promotes secure attachment. Unknown is the extent to which these effects are the result of the activation of C-Tactile afferents (CTs), the constellation of nerve fibers associated with affective touch, primarily located in the head and trunk of the body. The purpose of the present study was to compare dynamic touch (CTs activated) to static touch (CTs less activated) during a babywearing procedure among infants experiencing Neonatal Opioid Withdrawal Syndrome (NOWS). NOWS is a spectrum of clinical symptoms, including elevated heart rate (HR), associated with withdrawal from intrauterine opioid exposure. We hypothesized that stroking an infant's head during babywearing would amplify the pleasurable effect of babywearing as measured by changes in infant HR. Twenty-nine infants in a Neonatal Intensive Care Unit (NICU) in the Southwestern USA were worn in an infant carrier starting at five days old (M = 5.4, SD = 2.6; 46.2 % White, 26.9 % Latinx, 11.5 % Native American) and physiological readings were conducted daily; heart rates of infants and caregivers were taken every 15-seconds for 5-minutes, before, during, and after babywearing (30 min per phase). Each day infants alternated (randomly) in a static touch (hands-free babywearing) or dynamic touch condition (stroking the top of the infants' head at a velocity of 3 cm/s while babywearing). On average, infants completed 3 dynamic and 3 static babywearing sessions. Hospital and research staff participated in babywearing when a parent was not available (31.0 % of infants were exclusively worn by volunteers, 27.6 % were exclusively worn by parents). We analyzed the data using Hierarchical Linear Models due to the 3-level nested design (N = 29 infants, N = 191 readings, N = 11,974 heart rates). Compared to baseline (infant calm/asleep and without contact), infant's HRs significantly declined during and after babywearing, controlling for pharmacological treatment. These effects were significantly stronger during the dynamic touch condition (reduction in HR of 11.17 bpm) compared to the static touch condition (reduction in HR of 3.74 bpm). These effects did not significantly vary by wearer (mother, father, volunteer). However, differences between the dynamic and static conditions were significantly stronger in earlier babywearing sessions, potentially indicating a learning effect. There was evidence for a calming effect among caregivers as well, particularly in the dynamic touch condition, when caregivers were engaged in active touch. Activation of CTs appears to be an important mechanism in the physiological benefits of babywearing and in the symbiotic role of caregiver-infant attachment.

Head-tail-head neural wiring underlies gut fat storage in Caenorhabditis elegans temperature acclimation.

Animals maintain the ability to survive and reproduce by acclimating to environmental temperatures. We showed here that Caenorhabditis elegans exhibited temperature acclimation plasticity, which was regulated by a head-tail-head neural circuitry coupled with gut fat storage. After experiencing cold, C. elegans individuals memorized the experience and were prepared against subsequent cold stimuli. The cyclic adenosine monophosphate (cAMP) response element-binding protein (CREB) regulated temperature acclimation in the ASJ thermosensory neurons and RMG head interneurons, where it modulated ASJ thermosensitivity in response to past cultivation temperature. The PVQ tail interneurons mediated the communication between ASJ and RMG via glutamatergic signaling. Temperature acclimation occurred via gut fat storage regulation by the triglyceride lipase ATGL-1, which was activated by a neuropeptide, FLP-7, downstream of CREB. Thus, a head-tail-head neural circuit coordinated with gut fat influenced experience-dependent temperature acclimation.

Critical Review and Consensus Statement for Neural Monitoring in Otolaryngologic Head, Neck, and Endocrine Surgery.

BACKGROUND: Enhancing patient outcomes in an array of surgical procedures in the head and neck requires the maintenance of complex regional functions through the protection of cranial nerve integrity. This review and consensus statement cover the scope of cranial nerve monitoring of all cranial nerves that are of practical importance in head, neck, and endocrine surgery except for cranial nerves VII and VIII within the temporal bone. Complete and applied understanding of neurophysiologic principles facilitates the surgeon's ability to monitor the at-risk nerve. METHODS: The American Academy of Otolaryngology-Head and Neck Surgery (AAO-HNS) identified the need for a consensus statement on cranial nerve monitoring. An AAO-HNS task force was created through soliciting experts on the subject. Relevant domains were identified, including residency education, neurophysiology, application, and various techniques for monitoring pertinent cranial nerves. A document was generated to incorporate and consolidate these domains. The panel used a modified Delphi method for consensus generation. RESULTS: Consensus was achieved in the domains of education needs and anesthesia considerations, as well as setup, troubleshooting, and documentation. Specific cranial nerve monitoring was evaluated and reached consensus for all cranial nerves in statement 4 with the exception of the spinal accessory nerve. Although the spinal accessory nerve's value can never be marginalized, the task force did not feel that the existing literature was as robust to support a recommendation of routine monitoring of this nerve. In contrast, there is robust supporting literature cited and consensus for routine monitoring in certain procedures, such as thyroid surgery, to optimize patient outcomes. CONCLUSIONS: The AAO-HNS Cranial Nerve Monitoring Task Force has provided a state-of-the-art review in neural monitoring in otolaryngologic head, neck, and endocrine surgery. The evidence-based review was complemented by consensus statements utilizing a modified Delphi method to prioritize key statements to enhance patient outcomes in an array of surgical procedures in the head and neck. A precise definition of what actually constitutes intraoperative nerve monitoring and its benefits have been provided.

Safety and efficacy of occipital nerve stimulation for attack prevention in medically intractable chronic cluster headache (ICON): a randomised, double-blind, multicentre, phase 3, electrical dose-controlled trial.

BACKGROUND: Occipital nerve stimulation (ONS) has shown promising results in small uncontrolled trials in patients with medically intractable chronic cluster headache (MICCH). We aimed to establish whether ONS could serve as an effective treatment for patients with MICCH. METHODS: The ONS in MICCH (ICON) study is an investigator-initiated, international, multicentre, randomised, double-blind, phase 3, electrical dose-controlled clinical trial. The study took place at four hospitals in the Netherlands, one hospital in Belgium, one in Germany, and one in Hungary. After 12 weeks' baseline observation, patients with MICCH, at least four attacks per week, and history of being non-responsive to at least three standard preventive drugs, were randomly allocated (at a 1:1 ratio using a computer-generated permuted block) to 24 weeks of occipital nerve stimulation at either 100% or 30% of the individually determined range between paraesthesia threshold and near-discomfort (double-blind study phase). Because ONS causes paraesthesia, preventing masked comparison versus placebo, we compared high-intensity versus low-intensity ONS, which are hypothesised to cause similar paraesthesia, but with different efficacy. In weeks 25-48, participants received individually optimised open-label ONS. The primary outcome was the weekly mean attack frequency in weeks 21-24 compared with baseline across all patients and, if a decrease was shown, to show a group-wise difference. The trial is closed to recruitment (ClinicalTrials.gov NCT01151631). FINDINGS: Patients were enrolled between Oct 12, 2010, and Dec 3, 2017. We enrolled 150 patients and randomly assigned 131 (87%) to treatment; 65 (50%) patients to 100% ONS and 66 (50%) to 30% ONS. One of the 66 patients assigned to 30% ONS was not implanted and was therefore excluded from the intention-to-treat analysis. Because the weekly mean attack frequencies at baseline were skewed (median 15·75; IQR 9·44 to 24·75) we used log transformation to analyse the data and medians to present the results. Median weekly mean attack frequencies in the total population decreased from baseline to 7·38 (2·50 to 18·50; p<0·0001) in weeks 21-24, a median change of -5·21 (-11·18 to -0·19; p<0·0001) attacks per week. In the 100% ONS stimulation group, mean attack frequency decreased from 17·58 (9·83 to 29·33) at baseline to 9·50 (3·00 to 21·25) at 21-24 weeks (median change from baseline -4·08, -11·92 to -0·25), and for the 30% ONS stimulation group, mean attack frequency decreased from 15·00 (9·25 to 22·33) to 6·75 (1·50 to 16·50; -6·50, -10·83 to -0·08). The difference in median weekly mean attack frequency between groups at the end of the masked phase in weeks 21-24 was -2·42 (95% CI -5·17 to 3·33). In the masked study phase, 129 adverse events occurred with 100% ONS and 95 occurred with 30% ONS. None of the adverse events was unexpected but 17 with 100% ONS and eight with 30% ONS were labelled as serious, given they required brief hospital admission for minor hardware-related issues. The most common adverse events were local pain, impaired wound healing, neck stiffness, and hardware damage. INTERPRETATION: In patients with MICCH, both 100% ONS intensity and 30% ONS intensity substantially reduced attack frequency and were safe and well tolerated. Future research should focus on optimising stimulation protocols and disentangling the underlying mechanism of action. FUNDING: The Netherlands Organisation for Scientific Research, the Dutch Ministry of Health, the NutsOhra Foundation from the Dutch Health Insurance Companies, and Medtronic.

Magnetic resonance neurography of the head and neck: state of the art, anatomy, pathology and future perspectives.

Magnetic resonance neurography allows for the selective visualization of peripheral nerves and is increasingly being investigated. Whereas in the past, the imaging of the extracranial cranial and occipital nerve branches was inadequate, more and more techniques are now available that do allow nerve imaging. This basic review provides an overview of the literature with current state of the art, anatomical landmarks and future perspectives. Furthermore, we illustrate the possibilities of the three-dimensional CRAnial Nerve Imaging (3D CRANI) MR-sequence by means of a few case studies.

Cephalic Neuronal Vesicle Formation is Developmentally Dependent and Modified by Methylmercury and sti-1 in Caenorhabditis elegans.

Methylmercury (MeHg) is a potent neurotoxicant. The mechanisms underlying MeHg-induced neurotoxicity are not fully understood. Several studies have shown that protein chaperones are involved in MeHg toxicity. The protein co-chaperone, stress inducible protein 1 (STI-1), has important functions in protein quality control of the chaperone pathway. In the current study, dopaminergic (DAergic) cephalic (CEP) neuronal morphology was evaluated in the Caenorhabditis elegans (C. elegans) sti-1 knockout strain. In the control OH7193 strain (dat-1::mCherry + ttx-3::mCherry), we characterized the morphology of CEP neurons by checking the presence of attached vesicles and unattached vesicles to the CEP dendrites. We showed that the attached vesicles were only present in adult stage worms; whereas they were absent in the younger L3 stage worms. In the sti-1 knockout strain, MeHg treatment significantly altered the structures of CEP dendrites with discontinuation of mCherry fluorescence and shrinkage of CEP soma, as compared to the control. 12 h post treatment on MeHg-free OP50-seeded plates, the discontinuation of mCherry fluorescence of CEP dendrites in worms treated with 0.05 or 0.5 µM MeHg returned to levels statistically indistinguishable from control, while in worms treated with 5 µM MeHg a higher percentage of discontinuation of mCherry fluorescence persisted. Despite this strong effect by 5 µM MeHg, CEP attached vesicles were increased upon 0.05 or 0.5 µM MeHg treatment, yet unaffected by 5 µM MeHg. The CEP attached vesicles of sti-1 knockout strain were significantly increased shortly after MeHg treatment, but were unaffected 48 h post treatment. In addition, there was a significant interactive effect of MeHg and sti-1 on the number of attached vesicles. Knock down sti-1 via RNAi did not alter the number of CEP attached vesicles. Taking together, our data suggests that the increased occurrence of attached vesicles in adult stage worms could initiate a substantial loss of membrane components of CEP dendrites following release of vesicles, leading to the discontinuation of mCherry fluorescence, and the formation of CEP attached vesicles could be regulated by sti-1 to remove cellular debris for detoxification.

Symptomatology in head and neck district in coronavirus disease (COVID-19): A possible neuroinvasive action of SARS-CoV-2.

OBJECTIVE: The aim of this manuscript is to investigate transversally Ear Nose Throat (ENT) symptoms COVID-19 infection correlated and to study the neurotropism and neuroinvasiveness of the virus in the head-neck district through the investigation of the sense of smell, taste, tearing, salivation and hearing. METHODS: A total of 50 patients with laboratory-confirmed COVID-19 infection were included in our study. For each patient we evaluated the short version of the Questionnaire of Olfactory Disorders-Negative Statements (sQOD-NS), the Summated Xerostomia Inventory-Dutch Version (SXI-DV), The Standardized Patient Evaluation of Eye Dryness (SPEED), Schirmer test I, the Hearing Handicap Inventory For Adults (HHIA) and the Tinnitus Handicap Inventory (THI). All the tests we carried out were performed during the active phase of the symptomatology from COVID-19 (Condition A) and 15 after SARS-COV-2 RT-PCR test negative (Condition B). RESULTS: A total of 46 patients (92%) had olfactory dysfunction related to the infection. The 70% of patients reported gustatory disorders. Cough, fever, headache and asthenia were the most prevalent symptoms. There was a statistically significant difference (p < 0,001) in sQOD-NS, SXI-DV, SPEED, Schirmer test, HHIA and THI between Condition A and Condition B. CONCLUSIONS: In our population there was an alteration of the sense of taste, of the sense of smell, dry eyes and of the oral cavity and an auditory discomfort, symptoms probably linked to the neurotropism of the virus. Furthermore, anosmia, dysgeusia and xerostomia are early symptoms of COVID-19, which can be exploited for an early quarantine and a limitation of viral contagion.

Visualization of the greater and lesser occipital nerves on three-dimensional double-echo steady-state with water excitation sequence.

PURPOSE: To investigate the ability of three-dimensional double-echo steady-state with water excitation sequence (3D-DESS-WE) in detecting the greater occipital nerve (GON) and the lesser occipital nerve (LON). MATERIALS AND METHODS: We retrospectively reviewed 66 consecutive patients who underwent magnetic resonance imaging, including 3D-DESS-WE. Two readers evaluated the detectability [0 (poor) to 3 (excellent)] and thickness of the GON and LON. We calculated the average evaluation scores and interobserver variability for the detectability of the GON and LON. We also calculated the average nerve thickness for each of the two readers and the interobserver reproducibility for the thickness of the GON and LON. The interobserver variability was calculated using a weighted kappa analysis and the intraclass correlation coefficient (ICC) was used to evaluate the interobserver reproducibility of the nerve thickness. RESULTS: The respective average score, interobserver variability, thickness and interobserver reproducibility were 3.00, excellent (κ = 1.00), 1.07 ± 0.12 mm, and almost perfect (ICC = 0.82) for the GON and 1.81, good (κ = 0.73), 0.84 ± 0.11 mm, and substantial (ICC = 0.78) for the LON. The GON was significantly thicker than the LON (p < 0.001). CONCLUSION: The 3D-DESS-WE demonstrated excellent visualization of the GON and relatively good visualization of the LON.

Whole-animal connectomes of both Caenorhabditis elegans sexes.

Knowledge of connectivity in the nervous system is essential to understanding its function. Here we describe connectomes for both adult sexes of the nematode Caenorhabditis elegans, an important model organism for neuroscience research. We present quantitative connectivity matrices that encompass all connections from sensory input to end-organ output across the entire animal, information that is necessary to model behaviour. Serial electron microscopy reconstructions that are based on the analysis of both new and previously published electron micrographs update previous results and include data on the male head. The nervous system differs between sexes at multiple levels. Several sex-shared neurons that function in circuits for sexual behaviour are sexually dimorphic in structure and connectivity. Inputs from sex-specific circuitry to central circuitry reveal points at which sexual and non-sexual pathways converge. In sex-shared central pathways, a substantial number of connections differ in strength between the sexes. Quantitative connectomes that include all connections serve as the basis for understanding how complex, adaptive behavior is generated.

The Great Auricular Nerve: Anatomical Study with Application to Nerve Grafting Procedures.

BACKGROUND: When it comes to autogenous nerve grafting, the sural and great auricular nerve (GAN) are the 2 nerves predominately used for trigeminal and facial nerve repair. Arising from the second and third cervical ventral rami, the GAN emerges from the posterior border of the sternocleidomastoid coursing superiorly and anteriorly toward the ear. METHODS: Eleven sides from 5 Caucasian and 1 Asian cadaveric heads (all fresh-frozen) were used. One man and 5 women were used with an age at death ranging from 57 to 91 years, with a mean of 80.3 years. Measurements were made from the inferior border of the ear to the GAN, the GAN to the external jugular vein, and the inferior border of the mastoid process to the GAN; the proximal, medial, and distal diameters of the GAN and the length of the GAN that was obtained from this exposure were also measured. RESULTS: The mean distance from the inferior border of the mastoid process to the GAN, inferior border of the ear to the GAN, and GAN to the external jugular vein was 27.71, 31.03, and 13.28 mm, respectively. The mean length of the GAN was 74.86 mm. The mean diameter of its distal, middle, and proximal portions was 1.51, 1.38, and 1.58 mm, respectively. CONCLUSIONS: The GAN is an excellent option for use in nerve grafting for repair of, for example, facial dysfunction. In this study, we review our measurements, techniques for identification, and dissecting techniques for the GAN. The proximity to the operative area and minimal complications associated with GAN grafting might contribute to improved patient satisfaction and better outcomes regarding functional restoration.

To roll the eyes and snap a bite - function, development and evolution of craniofacial muscles.

Craniofacial muscles, muscles that move the eyes, control facial expression and allow food uptake and speech, have long been regarded as a variation on the general body muscle scheme. However, evidence has accumulated that the function of head muscles, their developmental anatomy and the underlying regulatory cascades are distinct. This article reviews the key aspects of craniofacial muscle and muscle stem cell formation and discusses how this differs from the trunk programme of myogenesis; we show novel RNAseq data to support this notion. We also trace the origin of head muscle in the chordate ancestors of vertebrates and discuss links with smooth-type muscle in the primitive chordate pharynx. We look out as to how the special properties of head muscle precursor and stem cells, in particular their competence to contribute to the heart, could be exploited in regenerative medicine.

Altered trunk head co-ordination in those with persistent neck pain.

BACKGROUND: Decreased neck motion and sensorimotor deficits have been identified in those with neck pain. It is thought that these might be related to altered reflex mechanisms between the neck, eyes and the vestibular system. Trunk, head co-ordination might also be altered in neck pain. OBJECTIVES: This study investigated trunk head co-ordination ability in subjects with neck pain compared to asymptomatic controls. METHOD: Twenty-four subjects with persistent neck pain and twenty-six age and gender matched healthy controls performed 3 trials of 3 trunk movements whilst trying to keep the head still - (1) alternate trunk movement to the left and right (2) trunk movement to the left (3) trunk movement to the right. Wireless motion sensors positioned over the sternum and the forehead measured trunk and head range and velocity of motion. ANALYSIS: ANOVA was used to compare trunk and head range and velocity of motion during the 3 tasks. RESULTS: Neck pain subjects had significantly less trunk movement (p < 0.05) and velocity (p=<0.02) as well as significantly increased head movement (p=<0.03) during most tasks compared to control subjects. DISCUSSION: The results of the study suggest that neck pain subjects have difficulty moving their trunk independently of their head. They are less able to keep the head still while moving the trunk and perform the tasks more slowly. These findings might be related to altered reflex activity of the cervico-collic reflex and sensorimotor control. Further research is required.

Management of Great Auricular Neuralgia Confirmed by Electrophysiologic Examination: A Case Report.

The great auricular nerve (GAN) is a sensory branch of the cervical plexus originating from the C2 and C3 nerve roots that innervates the external ear, mandibular angle, and parotid gland. Since idiopathic GAN neuralgia is a rare condition and branches of the GAN overlap with other cervical and cranial nerves, its diagnosis is challenging and can be confused with other facial neuralgias. This article describes the case of a 55-year-old woman with intractable unilateral periauricular and lateral head pain. No significant findings were found on cervical and brain imaging. At first, the patient was suspected to be suffering from trigeminal neuralgia or great occipital neuralgia; however, the symptoms persisted despite pharmacotherapy, cervical plexus and medial branch block, and repetitive transcranial magnetic stimulation. On the basis of an electrophysiologic examination, the patient was diagnosed as having GAN lesions. Pain subsided immediately after ultrasound-guided GAN block with local anesthetics and steroids. These findings indicate that electrophysiologic studies are helpful for accurately diagnosing patients with unclear pain in the periauricular and lateral head.

Clues to basis of exploratory behaviour of the C. elegans snout from head somatotropy.

Wave propagation during locomotory movements of Caenorhabditis elegans is constrained to a single dorso/ventral plane. By contrast, the tip of the head (snout) can make rapid exploratory movements in all directions relative to the body axis. These extra degrees of freedom are probably important for animals to seek and identify desirable passages in the interstices of the three-dimensional matrix of soil particles, their usual habitat. The differences in degrees of freedom of movement between snout and body are reflected in the innervation of the musculature. Along the length of the body, the two quadrants of dorsal muscle receive common innervation as do the two quadrants of ventral muscle. By contrast, muscles in the snout have an octagonal arrangement of innervation. It is likely that the exploratory behaviour of the snout is mediated by octant-specific motor and sensory neurons, together with their associated interneurons. The well-defined anatomical structure and neural circuitry of the snout together with behavioural observations should facilitate the implementation of models of the neural basis of exploratory movements, which could lead to an understanding of the basis of this relatively complex behaviour, a behaviour that has similarities to foraging in some vertebrates.This article is part of a discussion meeting issue 'Connectome to behaviour: modelling C. elegans at cellular resolution'.

Comparison of masseter muscle referred sensations after mechanical and glutamate stimulation: a randomized, double-blind, controlled, cross-over study.

Referred sensations (RS) are commonly found in various musculoskeletal pain conditions. Experimental studies have shown that RS can be elicited through glutamate injection and mechanical stimulation. Despite this, differences and similarities between these modalities in RS outcomes remain unclear. The aim of this study was to assess differences between mechanical-induced and glutamate injection-induced RS in the trigeminal region. The present randomized, double-blind, controlled, cross-over study recruited 60 healthy participants who were assessed in 2 different sessions. In both sessions, pressure was applied to the masseter muscle with 4 different forces (0.5, 1, 2, and 4 kg), and glutamate (1 mol/L or 0.25 mol/L) was injected into the same area. Participants rated their perceived masseter sensations and rated and drew any RS they experienced. No difference was found in number of participants reporting RS after glutamate injection compared with mechanical stimulation. More participants reported RS when the stimulus was painful compared with a nonpainful stimulus. Furthermore, it was shown that the more intense the stimulus, the higher the frequency of RS. Finally, RS centre-of-gravity location was similar between the 2 sessions. In summary, RS was elicited in healthy individuals through both modalities, and no differences in frequency of RS were observed in the orofacial region. Hence, RS does not seem to be modality-dependent, and only the painfulness of the stimulus caused an increase in frequency of RS. Finally, RS location for each participant was similar in both sessions possibly indicating a preferred location of referral. These findings may have implications for our understanding of RS in craniofacial pain conditions.

Forward head posture is associated with pressure pain threshold and neck pain duration in university students with subclinical neck pain.

OBJECTIVE: The aims of this study are to investigate the association between: (i) forward head posture (FHP) and pressure pain thresholds (PPTs); (ii) FHP and maladaptive cognitive processes; and (iii) FHP and neck pain characteristics in university students with subclinical neck pain. MATERIALS/METHODS: A total of 140 university students, 90 asymptomatic and 50 with subclinical neck pain, entered the study. Demographic data, anthropometric data, FHP, and PPTs were collected for both groups. In addition, pain characteristics, pain catastrophizing, and fear of movement were assessed for participants with neck pain. FHP was characterized by the angle between C7, the tragus of the ear, and the horizontal line. Correlation analysis and multivariate regression analysis were conducted. RESULTS: Participants with subclinical neck pain showed significantly lower PPTs than participants without neck pain (p < .05), but similar FHP (p > .05). No significant association was found between FHP and PPTs in the asymptomatic group. In the group of participants with subclinical neck pain, PPTs at the right trapezius and neck pain duration explained 19% of the variance of FHP (R2 = 0.23; adjusted R2 = 0.19; p < .05). CONCLUSION: This study suggests that FHP is not associated with PPTs in asymptomatic university students. In university students with subclinical neck pain, increased FHP was associated with right trapezius hypoalgesia and with neck pain of shorter duration. These findings are in contrast with current assumptions on the association between neck pain and FHP.

Trunk, head and pelvis interactions in healthy children when performing seated daily arm tasks.

Development of trunk and head supportive devices for children with neuromuscular disorders requires detailed information about pelvis, trunk and head movement in interaction with upper extremity movement, as these are crucial for daily activities when seated in a wheelchair. Twenty-five healthy subjects (6-20 years old) were included to obtain insight in the physiological interactions between these segments and to assess maturation effects. Subjects performed a maximum range of trunk and head movement tasks and several daily tasks, including forward and lateral reaching. Movements of the arms, head, pelvis, and sub-sections of the trunk were recorded with an optical motion capture system. The range of motion of each segment was calculated. Contributions of individual trunk segments to the range of trunk motion varied with movement direction and therefore with the task performed. Movement of pelvis and all trunk segments in the sagittal plane increased significantly with reaching height, distance and object weight when reaching forward and lateral. Trunk movement in reaching decreased with age. Head movement was opposite to trunk movement in the sagittal (> 50% of the subjects) and transverse planes (> 75% of the subjects) and was variable in the frontal plane in most tasks. Both trunk and head movement onsets were earlier compared to arm movement onset. These results provide insight in the role of the upper body in arm tasks in young subjects and can be used for the design of trunk and head supportive devices for children with neuromuscular disorders.