Electromyographic activity of sternocleidomastoid and masticatory muscles in patients with vestibular lesions

This study evaluated the electromyographic characteristics of masticatory and neck muscles in subjects with vestibular lesions. Surface electromyography of the masseter, temporalis and sternocleidomastoid muscles was performed in 19 patients with Ménière's disease, 12 patients with an acute peripheral vestibular lesion, and 19 control subjects matched for sex and age. During maximum voluntary clenching, patients with peripheral vestibular lesions had the highest co-contraction of the sternocleidomastoid muscle (analysis of covariance, p=0.02), the control subjects had the smallest values, and the patients with Ménière's disease had intermediate values. The control subjects had larger standardized muscle activities than the other patient groups (p=0.001). In conclusion, during maximum voluntary tooth clenching, patients with vestibular alterations have both more active neck muscles, and less active masticatory muscles than normal controls. Results underline the importance of a more inclusive craniocervical assessment of patients with vestibular lesions

Three-dimensional assessment of nose and lip morphology in North Sudanese subjects with Down syndrome

Objective: To detail the nasolabial morphologic characteristics of North Sudanese subjects with Down syndrome (DS). Materials and Methods: Nasolabial morphology was assessed three-dimensionally in 64 North Sudanese subjects with DS aged 4 to 34 years and in 682 sex- and age-matched controls. Three-dimensional facial coordinates were collected using a laser scan, and selected distances, angles, areas, and volumes were computed. Subject and reference data were compared by computing z-scores and Student's t-tests. Results: The nose was significantly smaller (area) in subjects with DS than in reference subjects, and it had a different shape (more flat angle of alar slope, more acute nasal tip angle). The vertical (nasal bridge length, nose height) and anteroposterior (nasal tip protrusion) dimensions were reduced, while the horizontal dimensions (alar base width, inferior widths of the nostrils) were increased. The nasolabial angle was increased. The cutaneous lip volume was significantly smaller, while the vermilion lip area was larger in the subjects with DS. The mouth and philtrum widths were significantly reduced, while the vermilion height was significantly increased. Conclusion: Analyzed subjects with DS had a hypoplastic nose and different upper and lower lips than did reference, normal subjects. (Angle Orthod. 2011;81:107-114.

The estimation of body center of mass kinematics in sport: proposal of a new protocol

The assessment of body Center of Mass (CoM) kinematics is an important measure in the analysis of sport movements since it is strictly related to balance and stability control [1]. Among the methods proposed to estimate CoM displacement, Segmental method appears to be suitable to investigate CoM kinematics in sport: human body is assumed as a system of rigid segments, and the whole-body CoM is calculated as the weighted average of the CoM of each segment. Each segment is defined by a set of landmarks, and their overall number represents a crucial choice in the protocol design process, being a compromise between accuracy and invasivity [2]. In the present study, using a motion capture system, we validated a protocol based upon the Segmental method, adopting a 14-landmarks anatomical model. Two sets of experiments were made. At first, our protocol was compared to the Ground Reaction Force method (GRF), accounted as a golden standard in CoM estimation. Subsequently, we investigated the aerial phase typical of many sports, comparing our protocol with: (1) an absolute reference, the parabolic regression of the vertical CoM trajectory during the time of flight; (2) two common approaches to estimate CoM kinematics in gait, known as Sacrum and Reconstructed Pelvis methods. Recognized accuracy indexes proved that the results obtained were comparable to the GRF; what is more, during the aerial phase our protocol showed to be significantly more accurate than the other two methods. The protocol assessed can therefore be adopted as a reliable tool for CoM kinematics estimation in further sport researches

Body center of mass displacements during walking with low- and high-heeled shoes

Walking is a natural activity that is very often performed wearing shoes. Among many other kinds of footwear, high-heeled shoes induce increased ankle plantar flexion, greater knee flexion, anterior pelvic tilt, and trunk extension [1]. The modifications in the arrangement of body segments cause an altered position of the body centre of mass (CoM). In the current study, we quantitatively compared the 3D displacement of CoM during flat-heeled and high-heeled gait. Eleven volunteer women (mean age, 24 years) walked wearing either low-heeled and high-heeled shoes (minimum height, 70 mm). On each subject, the 3D coordinates of 14 body landmarks were recorded by an optoelectronic motion analyzer. The body was segmented in 10 independent masses: head, torso, two upper arms and two lower arms (upper body); two upper legs and two lower legs (lower body). Using mean anthropometric data, the whole body CoM was computed, as well as its superior (uCoM) and inferior (iCoM) components [2]. The body CoM was evaluated during normalized stride cycles. High-heeled gait, compared to flat-heeled gait, had a significantly lower CoM at Right heel strike (p=0.024) and Left heel strike (p=0.030). The same findings were also observed for uCoM and iCoM. No significant differences were found at Right toe off. In addition, a significant forward displacement of the iCoM in high-heeled gait was observed at each of the three stages (R heel strike, p=0.017; L heel strike, p=0.034; R toe off, p=0.003). Similar results were found for the whole CoM (p=0.024, p=0.038, p=0.004). The uCoM in high-heeled gait, instead, was significantly more anterior than in flat-heeled gait only at R toe off (p=0.024). Our findings confirmed that wearing high-heeled shoes significantly alters the normal displacement of both components of the human CoM

Dribbling skill determinants in youth soccer players

Dribbling and pass-kick are the most frequently performed techniques during match play. While an extensive knowledge is available about kicking biomechanics, little is known about dribbling kinematics. Given that dribbling performance can assist in the talent identification process [1], we aim at finding the biomechanics determinants of this technique. A motion analysis system recorded the 3-D coordinates of 21 reflective markers placed upon the body of 10 youth sub-elite soccer players (12.6±0.37 years, 42.9±6.15 kg, 1.54 ± 0.07 m). Each participant performed 5 slalom-dribbling tests consisting of a 180° turning and four changes of direction. Since dribbling speed is a separating performance factor, players were split into two groups of 5 according to the execution time (“fast” and “slow”). Center of Mass (CoM) trajectory, Range of Motion (RoM), velocity and acceleration were computed along the three directions [2]. Mann-Whitney’s non-parametric tests were used for comparisons. Fast and slow players did not differ in terms of age, weight, body height, BMI, playing position and number of foot-ball contacts (p>0.05). While CoM average velocity and root mean square acceleration were similar in the two groups, CoM mediolateral and craniocaudal RoM were significantly lower (p<0.05) in faster players. Skilled players took less time in completing the test because they were able to drive the ball while running through a shorter path. Their CoM vertical and lateral displacements were significantly lower, meaning that, at a higher skill level, dribbling technique is delivered in a more effective and economical way

Morphometric parameters for nasal septum deviation identification in CBCT data

Advances in the upper airway imaging allow to better evaluate and understand their morphology, pathology and mechanics [1]. In particular, Cone beam CT technology (CBCT), with its isotropic spatial resolution, undistorted images, X-ray lower radiation exposure, versatility and relatively low cost, takes over other imaging modalities [2]. The purpose of this study is to evaluate whether CBCT scans can be valuable tools for the extraction of quantitative parameters to confirm the deviation of the nasal septum in a specific patient. First, we assessed the difference in angle of septal deviation, calculated as proposed by Orhan et al., among a control group and a patient group [3]. Subsequently, we evaluated the percentage difference between the volume of the upper airways in the right side and left side of the nose in the same sample. The measurements were performed on 23 CBCT scans of Caucasian adult women, divided into 7 control subjects and 16 patients. The results demonstrate that there is a significant difference both in the deviation angle (p<0.05) and in the volume difference between healthy and patient subjects (p<0.001). Duplicate measurements of the deviation angle and the volume found no significant difference (p>0.05); random errors explained 0.77% (angle) and 0.99% (volume) of the sample variance. Paired Student’s t tests were used for comparisons. In particular, the volume difference appears to be less sensitive to the presence of isolated cartilaginous ridges that increase the angle of deviation even if the septum is not pathological. This makes it more suited to the identification of this pathology. The obtained outcomes are encouraging and it is advisable to continue the study on a larger sample

Facial soft-tissue volumes in adult Northern Sudanese individuals with Down syndrome

Objective: To investigate dimensions and ratios of soft-tissue facial volumes of adult Northern Sudanese subjects with Down syndrome by using computerized anthropometric measurements. Design, Setting, and Patients: The 3D coordinates of soft-tissue facial landmarks were obtained by a computerized digitizer in 26 Northern Sudanese adult subjects with Down syndrome (18 men, 8 women, aged 17-34 years), and in 99 healthy Northern Sudanese controls (48 women, 51 men) of the same age range. From the landmarks, several facial volumes and volume ratios were calculated. Data were compared to those collected in healthy individuals by computing z-scores. Results: In subjects with Down syndrome, facial volumes were significantly smaller than in control subjects (Student’s t, p < 0.05). The patterns of deviation from the norm were similar in men and women. When compared to controls, subjects with Down syndrome had no differences in nose volume as a fraction of total facial volume and a larger total lip volume as a fraction of total facial volume; within the facial middle third, they had relatively larger upper lip volumes and relatively smaller nose volumes. Conclusions: The facial soft-tissue structures of subjects with Down syndrome differed from those of normal controls of the same age, sex and ethnic group: a reduced facial size was coupled with specific variations in the nasal and labial regions

Three-dimensional facial morphometry in patients rehabilitated with implant-supported prostheses

The aim of the present study was to assess a low-cost, non-invasive facial morphometric digitizer to assist the practitioner in three-dimensional soft-tissue changes before and after oral rehabilitation. The method should provide quantitative data to support an objective assessment of the facial esthetic outcome [1]. Twenty-two patients aged 45-82 years, all with edentulous maxilla and mandible, were assessed both before and after receiving their definitive complete implant-supported prostheses (each received 4-11 implants in each dental arch; full-arch fixed prostheses were made). The three-dimensional coordinates of 50 soft-tissue facial landmarks were collected with a non-invasive digitizer; labial and facial areas, volumes, angles and distances were compared without/ with the prostheses [2]. Dental prostheses induced significant reductions in the nasolabial, mentolabial and interlabial angles, with increased labial prominence (p<0.05, Wilcoxon test). Lip vermilion area and volume significantly increased; significant increments were found in the vertical and anteroposterior labial dimensions. The presence of the dental prostheses significantly (p<0.001) modified the three-dimensional positions of several soft-tissue facial landmarks. The current approach enabled quantitative evaluation of the final soft-tissue results of oral rehabilitation with implant-supported prostheses, without submitting the patients to invasive procedures. The method could assess the three-dimensional appearance of the facial soft tissues of the patient while planning the provisional prosthetic restoration, providing quantitative information to prepare the best definitive prosthesis. Dote ricerca: FSE, Regione Lombardi