Differences in temporal profile of brain responses by pleasantness of somatosensory stimulation in autistic individuals.

Purpose/Aim. Autistic individuals may show either hyper- or hypo- responsiveness to touch compared to non-autistic individuals. These behavioural responses depend on perceptual and evaluative mechanisms, which unfold sequentially and thus can be distinguished by exploring the timing of neural responses. In this study, we examined neural response timing to pleasant, unpleasant, and affectively neutral textures, to determine whether these perceptual versus evaluative subprocesses differ in autism and how each subprocess contributes to behavioural responses.Materials and Methods. Our sample included n = 13 autistic and n = 14 non-autistic adults who completed functional magnetic resonance imaging. We analysed early, intermediate, and late phases of the tactile response, derived from studies of noxious tactile stimulation, to three different textures.Results. The autistic group showed distinct differences from the non-autistic group to each of the textures, showing earlier, somatosensory differences in response to the pleasantly and unpleasantly rated textures and later, frontomotor differences in response to the neutrally rated texture. Further, reduced early phase response to the pleasant texture correlated with increased sensory seeking behaviour.Conclusions. While preliminary, these results suggest distinct patterns between autistic and non-autistic individuals in how the neural response to touch unfolds and its correspondence with the perceived pleasantness of tactile experience. The findings suggest perceptual differences in response to affectively charged textures and evaluative differences in response to neutral, ambiguous textures. These temporal properties may inform future studies of tactile processing in autism, lending a better understanding of how individuals differ in their sensory experiences across contexts.

Initially intact neural responses to pain in autism are diminished during sustained pain.

Pain assessments typically depend on self-report of the pain experience. Yet, in individuals with autism spectrum disorders, this can be an unreliable due to communication difficulties. Importantly, observations of behavioral hypo- and hyperresponsivity to pain suggest altered pain sensitivity in autism spectrum disorder. Neuroimaging may provide insight into mechanisms underlying pain behaviors. The neural pain signature reliably responds to painful stimulation and is modulated by other outside regions, affecting the pain experience. In this first functional magnetic resonance imaging study of pain in autism spectrum disorder, we investigated neural responses to pain in 15 adults with autism spectrum disorder relative to a typical comparison group (n = 16). We explored temporal and spatial properties of the neural pain signature and its modulators during sustained heat pain. The two groups had indistinguishable pain ratings and neural pain signature responses during acute pain; yet, we observed strikingly reduced neural pain signature response in autism spectrum disorder during sustained pain and after stimulus offset. The posterior cingulate cortex, a neural pain signature modulating region, mirrored this late signal reduction in autism spectrum disorder. Intact early responses, followed by diminished late responses to sustained pain, may reflect altered pain coping or evaluation in autism spectrum disorder. Evidence of a dichotomous neural response to initial versus protracted pain may clarify the coexistence of both hypo- and hyperresponsiveness to pain in autism spectrum disorder.

Circulating Omentin-1 and Chronic Painful Temporomandibular Disorders.

AIMS: To investigate the relationship between omentin-1 levels and painful temporomandibular disorders (TMD). METHODS: In a case-control design, chronic painful TMD cases (n = 90) and TMD-free controls (n = 54) were selected from participants in the multisite OPPERA study (Orofacial Pain: Prospective Evaluation and Risk Assessment). Painful TMD case status was determined by examination using established Research Diagnostic Criteria for TMD (RDC/TMD). Levels of omentin-1 in stored blood plasma samples were measured by using an enzyme linked immunosorbent assay. Binary logistic regression was used to calculate the odds ratios (ORs) and 95% confidence limits (CLs) for the association between omentin-1 and painful TMD. Models were adjusted for study site, age, sex, and body mass index. RESULTS: The unadjusted association between omentin-1 and chronic painful TMD was statistically nonsignificant (P = .072). Following adjustment for covariates, odds of TMD pain decreased 36% per standard deviation increase in circulating omentin-1 (adjusted OR = 0.64; 95% CL: 0.43, 0.96; P = .031). CONCLUSION: Circulating levels of omentin-1 were significantly lower in painful TMD cases than controls, suggesting that TMD pain is mediated by inflammatory pathways.

Tooth loss and obstructive sleep apnea signs and symptoms in the US population.

PURPOSE: The aim of this study is to investigate the relationship between tooth loss and signs and symptoms of obstructive sleep apnea (OSA) in a representative sample of the general US population. METHODS: Data were from 7305 men and women aged ≥25 years participating in the 2005-2008 National Health and Nutrition Examination Survey. Tooth loss, occlusal contacts, and denture use were determined by dental examination. Four cardinal OSA signs and symptoms were evaluated by questions based on American Academy of Sleep Medicine criteria. Adults with ≥2 signs/symptoms of OSA were classified at high-risk of OSA. Prevalence ratios (PR) and 95 % confidence limits (CL) from log binomial regression models estimated the strength of association between tooth loss and high-risk for OSA, adjusting for demographic characteristics, body mass index, dentures, and sleep duration. RESULTS: Prevalence of high-risk for OSA increased 2 % for each additional lost tooth (PR = 1.02, 95 % CL, 1.01, 1.03) among adults aged 25 to 65 years. When tooth loss was modeled as an ordinal variable with 0-4 lost teeth as the referent category, adjusted prevalence of high-risk for OSA was as follows: 25 % greater in those missing 5-8 teeth (PR = 1.25, 95 % CL, 1.07, 1.46); 36 % greater in those missing 9-31 teeth (PR = 1.36, 95 % CL, 1.06, 1.73); and 61 % greater in the edentulous (PR = 1.61, 95 % CL, 1.11, 2.33). CONCLUSION: Tooth loss may be an independent risk factor for OSA.

Periodontitis and Sleep Disordered Breathing in the Hispanic Community Health Study/Study of Latinos.

STUDY OBJECTIVES: To investigate the association between sleep disordered breathing (SDB) and severe chronic periodontitis. DESIGN: Cross-sectional data analysis from the Hispanic Community Health Study/Study of Latinos. SETTING: Community-based setting with probability sampling from four urban US communities. PARTICIPANTS: 12,469 adults aged 18-74 y. INTERVENTIONS: None. MEASUREMENTS AND RESULTS: Severe chronic periodontitis was defined using the Centers for Disease Control and Prevention/American Academy of Periodontology case classification based on full-mouth periodontal assessments performed by calibrated dentists. SDB was evaluated in standardized home sleep tests, and defined as the number of apnea plus hypopnea events associated with ≥ 3% desaturation, per hour of estimated sleep. SDB was quantified using categories of the apnea-hypopnea index (AHI): 0.0 events (nonapneic); 0.1-4.9 (subclinical); 5.0-14.9 (mild); and ≥ 15 (moderate/severe). Covariates were demographic characteristics and established periodontitis risk factors. C-reactive protein was a potential explanatory variable. Using survey estimation, multivariable binary logistic regression estimated odds ratios (OR) and 95% confidence limits (CL). Following adjustment for confounding, the SDB and periodontitis relationship remained statistically significant, but was attenuated in strength and no longer dose-response. Compared with the nonapneic referent, adjusted odds of severe periodontitis were 40% higher with subclinical SDB (OR = 1.4, 95% CL: 1.0, 1.9), 60% higher with mild SDB (OR = 1.6, 95% CL: 1.1, 2.2) and 50% higher with moderate/severe SDB (OR = 1.5, 95% CL: 1.0, 2.3) demonstrating an independent association between SDB and severe periodontitis. CONCLUSIONS: This study identifies a novel association between mild sleep disordered breathing and periodontitis that was most pronounced in young adults.

Effect of hydration on the tactile and thermal sensitivity of the lip.

The vermilion lip is a body site particularly susceptible to water loss. Therefore, the role of hydration in tactile perception at the lip was investigated. A series of measures of tactile performance and response were obtained from 22 female subjects, namely: (1) the subjective assessment of lip feel, (2) tactile sensitivity, (3) spatial acuity, (4) thermal sensitivity, and (5) the subjective assessment of thermal stimulation. These measures were obtained from lips in their natural (untreated) state, and lips that had been treated using a hydrating preparation. The preparation altered the subjective feel of the lips consistent with the treatment increasing lip hydration and compliance. Hydrated lips showed greater sensitivity to light touch, and there was a trend toward the lip's thermal sensitivity being altered consistent with the lip treatment having a physical cooling effect. Spatial acuity was unaltered by the state of lip hydration. The sensitivity changes on hydration were proposed to have mechanical basis.

Obstructive sleep apnea in association with periodontitis: a case-control study.

PURPOSE: Periodontitis is associated with several cardio-metabolic disorders that are co-morbid with sleep-disordered breathing. A relationship between periodontitis and obstructive sleep apnea (OSA) is plausible, but has received little attention. This study investigated the strength of association between periodontitis and risk for OSA. METHODS: In this case-control study, cases had moderate or severe periodontitis (n = 50, 32.5%) and controls had gingivitis or slight periodontitis (n = 104, 67.5%). Sixty-one males (39.6%) and 93 females (60.4%) with a mean age of 61 years were sampled from the dental hygiene preventive care clinic in the School of Dentistry at the University of North Carolina at Chapel Hill between February and April 2011. Patients received a full mouth periodontal examination that included probing pocket depths and clinical attachment levels at 6 sites per tooth. The case definition for moderate or severe periodontitis was that of the American Dental Association (ADA). Risk for OSA was determined by the 4 item "STOP" OSA screening questionnaire, which assesses self-reported snoring, excessive daytime sleepiness, witnessed apnea during sleep and history of hypertension. Demographic, general health and orofacial characteristics were recorded that were considered putative predictors of either periodontitis or OSA. A multivariate binary logistic regression assessed odds of moderate or severe periodontitis according to OSA risk with adjustment for potential confounders. RESULTS: In all, 59 patients (38.3%) screened at high risk for OSA by providing 2 or more affirmative responses on the STOP questionnaire. Sixty percent of periodontitis cases (n = 30) screened high risk of OSA compared with only 28% of controls (n = 29). Cases were 4.1 times more likely (95% CI: 1.9, 11.4) to be at high risk for OSA than controls (p = 0.007) after adjustment for potential confounders. CONCLUSION: A significant association was observed between moderate or severe periodontitis and risk for OSA.

Sensory retraining: a cognitive behavioral therapy for altered sensation.

Sensory retraining teaches the patient to ignore or blot out postinjury unpleasant orofacial sensations to optimally tune into and decipher the weakened and damaged signals from the tissues. Sensory retraining is a simple, inexpensive, noninvasive exercise program, which initiated shortly after injury, can lessen the objectionable impression of orofacial altered sensations. Sensory retraining exercises are most effective on decreasing the perceived burden associated with hypoesthetic orofacial altered sensations.

Quantitative assessment of pleasant touch.

The hedonic attributes of tactile stimulation are important to one's quality of life, yet they have rarely been studied scientifically. The earliest experimental investigations suggested soft and smooth materials as pleasant, those that were stiff, rough, or coarse as unpleasant. More recent studies conducted by the authors and described herein obtained ratings of pleasantness of different textured materials stroked across the skin of multiple body sites at controlled velocities and forces of application. Statistically significant interactions between materials, sites, velocities, forces and subject sex attest to the complexity of the percept. Less pleasant percepts arose from stimuli that were rougher. However, the difficulty in making further general statements regarding hedonic touch raises questions as to whether the body surface can be mapped affectively in a meaningful manner with a single stimulus and indeed whether pleasantness-to-touch can be viewed as a unidimensional construct.

Functional outcomes of cleft lip surgery. Part I: Study design and surgeon ratings of lip disability and need for lip revision.

OBJECTIVE: Children with a cleft of the upper lip exhibit obvious facial disfigurement. Many require multiple lip surgeries for an optimal esthetic result. However, because the decision for lip revision is based on subjective clinical criteria, clinicians may disagree on whether these surgeries should be performed. To establish more reliable, functionally relevant outcome criteria for evaluation and treatment planning, a clinical trial currently is in progress. In this article, the design of the clinical trial is described and results of a study on subjective evaluations of facial form by surgeons for or against the need for lip revision surgery are presented. DESIGN: Parallel, three-group, nonrandomized clinical trial and subjective evaluations/ratings of facial views by surgeons. SUBJECTS: For the clinical trial, children with repaired cleft lip and palate scheduled for a secondary lip revision, children with repaired cleft lip and palate who did not have lip revision, and noncleft children. For the subjective evaluations, surgeons' facial ratings of 21 children with repaired cleft lip. ANALYSIS: Descriptive and Kappa statistics assessing the concordance of surgeons' ratings of (a) repeated facial views and (b) a recommendation of revision on viewing the prerevision and postrevision views. RESULTS: The surgeons' consistency in rating repeated views was moderate to excellent; however, agreement among the surgeons when rating individual participants was low to moderate. CONCLUSIONS: The findings suggest that the agreement among surgeons was poor and support the need for more objective measures to assess the need for revision surgery.

Functional outcomes of cleft lip surgery. Part IV: Between- and within-participant variables affecting lip vermilion sensory thresholds.

OBJECTIVE: Compare neurosensory assessments for participants with and without a cleft lip; identify between- and within-participant variables affecting sensory thresholds on the vermilion of participants with cleft lip. DESIGN: A parallel group, nonrandomized clinical trial. SUBJECTS: There were 56 participants with cleft lip and 37 noncleft participants. ANALYSIS: Two-point perception and warmth and cool detection thresholds were measured on the right and left sides of the upper and lower vermilion. A cotton-tip stick, stroked across the skin, was used to identify altered sensation. Linear mixed effects modeling was used to examine the effects of between- and within-participant variables on the thresholds. RESULTS: Threshold values on the upper and lower vermilion were similar for cleft and noncleft participants and were unaffected by the presence of a cleft on the side tested. Participants with cleft lip who reported hyposensitive altered sensations had higher two-point thresholds on the upper lip than those who reported hypersensitivity. Participants with cleft lip who reported altered midface sensation had lower warmth detection, but higher cool detection thresholds, on the lower vermilion than participants with cleft lip who did not report altered sensation. Participants with bilateral cleft lip had lower warmth detection thresholds on the upper vermilion than participants with unilateral cleft lip. CONCLUSIONS: Although participants with cleft lip and noncleft participants exhibit similar thermal and two-point discrimination, on average, differences exist among subgroups of participants with cleft lip that may reflect central disturbances in the processing of somatosensory stimuli.

Report of altered sensation in patients with cleft lip.

OBJECTIVE: To determine whether patients with cleft lip have normal perioral sensation. DESIGN: Each subject was carefully questioned about the following: sensation in the face at rest, light touch of different areas, and sensation in natural situations (e.g., exposure to cold weather) that reveal sensory abnormalities. A cotton-tip applicator stick was stroked lightly across the facial skin. The subject's descriptions of the evoked sensations were used to identify and outline areas with abnormal sensation. SETTING: Data were obtained from subjects participating in a longitudinal, university-based study of the functional outcomes of lip revision surgery. PATIENTS: Seventeen patients with cleft lip and 12 control subjects (aged 7 to 22 years, mean 12.9 years) participated. RESULTS: In contrast to control subjects, 9 of 16 patients (56%) reported loss in sensation, described as decreased touch, scratch, tickle, or tingle intensity. Six other patients (38%) reported additional sensation, described as increased scratch, tickle, or tingle intensity. In eight patients, the altered sensation was restricted to the skin area flanking and including the visible scar, encompassing no more than 25% of the total area bound by the inferior nose, nasolabial grooves and inferior vermilion. In seven patients (unilateral cleft), the altered area extended to the contralateral, noncleft side of the upper lip or onto the philtrum. CONCLUSIONS: In contrast to the literature, sensation in the upper lip of many patients with cleft lip is not normal. Loss in sensation is exhibited most commonly and limited largely to the skin overlying tissues traumatized during reconstructive surgery.

Psychophysical assessment of patients with posttraumatic neuropathic trigeminal pain.

This article reviews the utility of psychophysical approaches in the assessment of posttraumatic neuropathic trigeminal pain. Methods of quantitative sensory testing are derived from psychophysical principles and provide a widely accepted means for characterizing sensory dysfunction in patients who experience injury to the trigeminal nerve. No published study, however, has sought to compare sensory findings from trigeminal nerve-injured patients who develop neuropathic pain with those from trigeminal nerve-injured patients who remain pain-free. Moreover, sensory testing data from trigeminal nerve-injured patients with pain have been published in only a few reports. As a result, remarkably little is known about sensory factors associated with the development of posttraumatic trigeminal neuralgia. Review of the separate literatures suggests that both trigeminal nerve-injured patients with pain and pain-free trigeminal nerve-injured patients exhibit grossly similar impairments in sensory function. In addition, trigeminal nerve-injured patients with pain may be more likely to report cold allodynia than patients without pain and to exhibit signs of central sensitization such as allodynia to light brushing tactile stimuli and abnormal temporal summation of pain. New studies using state-of-the-art psychophysical methods are needed to search for sensory markers that bear on the development of pain. Moreover, the relationship between psychophysical indices of central sensitization and measures of clinical pain should be addressed to obtain a better understanding of the underlying pathophysiology.

Lingual tactile acuity, taste perception, and the density and diameter of fungiform papillae in female subjects.

A growing body of evidence suggests that individuals who differ in taste perception differ in lingual tactile perception. To address this issue, spatial resolution acuity was estimated for 83 young adult females (52 Asians and 31 Caucasians) by their ability to examine with the tongue and identify embossed letters of the alphabet. Ratings of the magnitude of the bitterness of 0.0032M 6-n-propylthiouracil (PROP) were obtained to characterize subjects' taste perception. The density and diameter of fungiform papillae on the anterior tongues of the Asian subjects were measured also. Subjects who rated the bitterness of PROP as very or intensely strong (supertasters) were found to be about 25% more tactually acute than subjects who rated the bitterness as moderate to strong (medium tasters) and twice as acute as subjects who rated it as nondetectable or weak (non-tasters; P<.0001): The threshold heights for letter recognition averaged 2.8, 3.5 and 5.4 mm, respectively, for the Asian subjects and 2.6, 3.2, and 5.1 mm for the Caucasian subjects. The thresholds correlated highly with subjects' ratings of bitterness (rho=-0.84, P<.0001), and for the Asian subjects with the density (rho=-0.84, P<.0001) and diameter (rho=0.66, P<.0001) of fungiform papillae. Mean densities varied from 54.4 cm(-2) (non-tasters) to 106.5 cm(-2) (medium tasters) to 143.7 cm(-2) (supertasters; P<.0001). These findings confirm that individuals who differ in taste (PROP) sensitivity also differ in lingual tactile acuity. Tactile and taste sensitivities covary and reflect individual differences in the density and diameter of fungiform papillae on the anterior tongue.

Mechanosensory and thermosensory changes across the border of impaired sensitivity to pinprick after mandibular nerve injury.

PURPOSE: The study goal was to determine how sensory function varies across the border of impaired sensitivity to pinprick in patients with mandibular nerve injuries. PATIENTS AND METHODS: Borders of decreased sensitivity to pinprick were mapped in 15 patients who reported altered sensation. Four mechanoreceptive, 2 thermoreceptive, and 2 thermonociceptive functions were studied at 5 sites separated by 0.6 cm across the border. The tests were repeated to evaluate day-to-day consistency in the pattern of variation for each sensory measure. RESULTS: The estimates of sensory function were not found to vary in a systematic manner from outside to inside the pinprick-impaired area for all patients for any of the 8 tests. However, for every test, some patients exhibited large variations. On average, the magnitudes of loss in contact detection, subjective intensity of light touch, and direction discrimination were greatest; the magnitudes of loss in 2-point perception and in heat and cold pain perception were least. Some patients provided no evidence of impairment on certain tests. For some patients, the estimates suggested increased sensitivity within the pinprick-impaired area (eg, to noxious cold stimuli). CONCLUSIONS: Although certain patients exhibit impairment, there is no obligatory loss in light touch, 2-point perception, direction discrimination, or temperature perception across the border of decreased sensitivity to pinprick. The differences among patients suggest that the data from individual patients should be evaluated in clinical studies and in clinical practice. Researchers should not rely solely on average values and summary statistics.