Torticollis Research Articles

Head tilt in 6 Ankole-Watusi cattle (Bos taurus ankole) with chronic exudative cornual sinusitis.

Ankole-Watusi cattle, Bos taurus ankole, have a unique wide-based horn structure with a large communication to the frontal sinus compared to other cattle breeds. A total of 6 cases of cornual sinusitis presented at the Toronto Zoo and Disney's Animal Kingdom Lodge® and Disney's Animal Kingdom® Theme Park with a head tilt. Clinically, 4 of the 6 cases had concurrent otitis at the time of initial clinical observation. Medical management was the standard across all cases with limited surgical success in 2 cases. Due to intractable and progressive clinical signs despite treatment attempts, euthanasia and postmortem examinations were performed. All animals had gross and histologic evidence of cornual sinusitis with massive mucoid exudate in either 1 or both horns. Fluid accumulation and sinusitis within the cornual sinus should be considered a differential diagnosis in Ankole-Watusi cattle with a head tilt.

Association among raised intraventricular pressure, clinical signs, and magnetic resonance imaging findings in dogs with congenital internal hydrocephalus.

Dogs with internal hydrocephalus do not necessarily have high intraventricular pressure (IVP). Not all reported MRI findings indicate high IVP and some clinical signs might be associated with elevated IVP and syringomyelia. Fifty-three dogs. Cross-sectional study. Clinical signs and MRI findings were evaluated for an association of IVP >12 mm Hg and syringomyelia. High IVP was associated with obtundation OR 4.64 (95% CI 1.27-16.93) (P = .02), head tilt OR 6.42 (95% CI 1.08-37.97) (P = .04) and nystagmus OR 8.24 (95% CI 1.44-47.07) (P = .02). Pain was associated with syringomyelia OR 3.4 (95% CI 0.98-11.78) (P = .05). The number of affected ventricles was associated with high IVP OR 2.85 (95% CI 0.97-8.33) (P = .05) and syringomyelia OR 12.74 (95% CI 2.93-55.4) (P = .0007). Periventricular edema OR 24.46 (95% CI 4.54-131.77), OR 7.61 (95% CI 1.91-30.32) (P < .0002, P = .004) and signal void sign OR 17.34 (95% CI 4.01-74.95), OR 4.18 (95% CI 1.16-15.02) (P < .0001, P = .03) were associated with high IVP and syringomyelia. The probability for syringomyelia is lower with disruption of the internal capsule OR 0.19 (95% CI 0.05-0.72) (P = .01) and higher VBR OR 0.25 (95% CI 0.1-0.63) (P = .004). Previously reported MRI findings are not predictive of high IVP. Clinical signs and MRI findings should be used to make a diagnosis of internal hydrocephalus in dogs with or without high IVP.

Effects of Physical Activity Level and Sedentary Behavior on the Musculoskeletal System in Young Adults

Aim: The aim of this study is to investigate the relationship between the level of physical activity and sedentary behavior in young adults aged 18-35 and to evaluate the effects of this relationship on musculoskeletal pain, posture, muscle shortness, and trunk muscle endurance. Methods: In this cross-sectional descriptive study, conducted at the Faculty of Health Sciences of a university between March 2018 and August 2018, 219 students were included. Data were obtained by using the case report form which determines the demographic characteristics and sedentary behavior of the students, The International Physical Activity Index - short form, posture analysis form, muscle shortness evaluation form, and trunk muscle endurance evaluation form. Results: In the study, 66.2% of patients were female and 33.8% were male. In the evaluation of physical activity level, the ratio of highly active individuals in males, and inactive and insufficiently active individuals in females was significantly higher (p &amp;lt;0.05). Musculoskeletal pain was significantly higher in inactive and insufficiently active individuals (p&amp;lt;0.001). A negative correlation existed between physical activity level and pain frequency, duration, and scores (p&amp;lt;0.001). There was a positive correlation between trunk endurance tests and physical activity and exercise participation. Non-exercisers showed shortening of lumbar extensor muscles and gastrosoleus, with increased thoracic kyphosis (p&amp;lt;0.05). Daily sitting time correlated positively with elbow, wrist, and knee pain, and lumbar lordosis (p&amp;lt;0.05). Those spending more time at the computer experienced higher levels of head-neck and elbow pain, pain duration, muscle shortness, thoracic kyphosis, shoulder protraction, and anterior head tilt (p&amp;lt;0.05). Conclusion: In young adults, increasing physical activity and reducing daily sitting time are necessary to prevent musculoskeletal pain and reduce postural deformities. Keywords: Musculoskeletal diseases, musculoskeletal pain, physical exertion, posture, sedentary behavior, trunk muscular endurance, young adult.

A novel classification of congenital cervicothoracic scoliosis: identification of coronal subtypes and their prognostic significance.

To propose a novel classification system for stratifying coronal curve patterns in congenital cervicothoracic scoliosis with hemivertebrae (CTS-HV). Type A: regional cervicothoracic deformity only disturbing the balance of head-neck-shoulder complex; Type B: cervicothoracic deformity with significant trunk tilt to the convex side; Type C: cervicothoracic deformity with a significant compensatory thoracic curve. The reliability and reproducibility were assessed via the Kappa test. The differences among different subtypes in deformity parameters and bony structures were compared to identify the causative factors predisposing to different subtypes. 98 patients were classified into Type A (47 cases), Type B (31 cases), and Type C (20 cases). The Kappa test showed excellent reliability (Kappa value = 0.847) and reproducibility (Kappa value = 0.881). The proportions of Klippel-Feil syndrome in Types B (71.0%) and C (85.0%) were significantly higher than in Type A (46.8%; all P < 0.05). Type A (66.0%) and Type B (71.0%) predominantly had their hemivertebra (HV) at T3 or T4, while Type C (75%) mostly had HV at T1 or T2. Type B exhibited the most severe trunk tilt, head shift, neck tilt, head tilt, and coronal balance distance (all P < 0.05). Type C had the lowest T1 tilt and first rib angle despite the greatest cervicothoracic Cobb angle (all P < 0.05). This novel reliable classification allows a better understanding of structural diversity and different coronal compensatory mechanisms for the natural progression of CTS-HV. It can contribute to determining the individualized treatment strategy and standardizing academic communication for this rare clinical entity.

Amplification of vibration induced nystagmus in patients with peripheral vestibular loss by head tilt.

In patients with unilateral loss of vestibular function (UVL) vibration of the skull leads to a response of the vestibulo-ocular reflex (VOR) called vibration-induced nystagmus (VIN), with slow phases usually directed toward the paretic ear. This response is thought to result from the difference between the neural discharge in semicircular canal afferents from the healthy and the affected labyrinth. The brain interprets this difference as a sustained imbalance in angular (rotational) vestibular tone, which in natural circumstances would only occur when the head was rotating at a constant acceleration. To study this effect, we used a contemporary model of the neural network that combines sensory information about head rotation, translation, and tilt relative to gravity to estimate head orientation and motion. Based on the model we hypothesize that in patients with UVL, the brain may estimate not only a "virtual" rotation from the induced canal imbalance but also a subsequent "virtual" translation from the incorrect computation of the orientation of the head relative to gravity. If this is the case, the pattern of vibration-induced nystagmus will depend on the orientation of the head relative to gravity during the stimulation. This model predicts that this "virtual" translation will alter the baseline VIN elicited with the head upright; augmenting it when the affected ear is down and diminishing it when the affected ear is up. Confirming this hypothesis, we recorded VIN in 3 patients with UVL (due to vestibular neuritis) in upright, right ear-down, and left ear-down positions and each showed the expected pattern. From a practical, clinical view, our results and modeling suggest that positional VIN might reveal a hidden imbalance in angular vestibular tone in patients with UVL, when patients have equivocal signs of a vestibular imbalance, such as a minute amount of spontaneous or vibration-induced nystagmus with the head upright. This research provides insights into the underlying mechanisms of vestibular processing, the analysis of nystagmus in patients with UVL, and guides the design of a new bedside diagnostic test to assess vestibular function in patients with dizziness and imbalance.

Increased Perception of Head Tilt to Galvanic Vestibular Stimulation Correlates to Motion Sickness Susceptibility in Vestibular Migraine.

Vestibular migraine is associated with vertigo, persistent swaying, tilting, and disorientation, which suggests a heightened sensitivity of the neural mechanisms subserving spatial orientation. Whether a heightened sense of motion to vestibular stimulation in vestibular migraine is associated with sensitivity to visual motion (visual dependency) or physical motion (motion sickness susceptibility) is unclear. The aim of this study was to explore whether a heightened sense of self-motion sensitivity in vestibular migraine is associated with visual dependency or motion sickness susceptibility. This is a prospective cross-over study. Fifteen participants with vestibular migraine and 20 healthy controls (all right handed) were included in this study. In the main experiment, participants were asked to align a rod to the perceived head position. Head tilt was generated by DC galvanic vestibular stimulation at 1 mA to produce head tilts to the right (left anodal/right cathodal stimulation, LA/RC) or left (right anodal/left cathodal, RA/LC). The perception of head tilt was measured in a dark room using laptop software that allowed participants to turn an illuminated rod to any angle about the midpoint. Participants were instructed to align the rod to the perceived head position before and during galvanic stimulation and the line angle was saved. Head position was objectively monitored with an ultrasound motion system. After completing the perceptual test, visual dependency was measured with a static and rotating background and the Motion Sickness Susceptibility Questionnaire (MSSQ) was completed. In an upright head position, without stimulation, the perceived head position was 1.1 degrees in controls and -0.69 degrees in vestibular migraine participants with no significant difference between groups. During galvanic vestibular stimulation, participants with vestibular migraine had an increased perception of head tilt compared with controls (RA/LC: controls -4.7 degrees and vestibular migraine -9.29, p = 0.002; and LA/RC: controls 6.5 degrees and vestibular migraine 11.12 degrees, p = 0.017), although the size of head movement was similar between groups. The average perception of head tilt correlated to the MSSQ score, but not to the degree of visual dependency in a static or moving background. A heightened sensitivity of the vestibular system to vestibular stimulation in vestibular migraine is consistent with reports of self-motion sensitivity in vestibular migraine.

Reference ranges and test-retest reliability of subject visual horizontal from different head-tilt angles in young healthy adults

Objective:To establish the normal values of subjective visual horizontal（SVH） under different head tilt angles, analyze the test-retest reliability, and provide a normal value reference for the refined diagnosis and functional assessment of SVH in clinical vestibular disorders. Methods:Thirty-one healthy young people were selected to wear visual reality glasses to test SVH data in five different head tilt angles: upright head position 0°, head tilted 45°to the left（L45°）, head tilted 45° to the right（R45°）, head tilted 90° to the left（L90°）, and head tilted 90° to the right（R90°）, and were re-tested 2 weeks later. Results:①The normal values of SVH at 0°, L45°, R45°, L90°, and R90°were 0.30±1.32, 5.94±5.54, -11.44±5.32, -0.87±8.63, -2.70±8.02, respectively. ②The 95% confidence intervals of SVH at 0°, L45°, R45°, L90°, and R90° were: （-2.34,2.94）,（-5.14,17.02）,（-22.08,-0.80）,（-18.13,16.39）,（-18.74，13.34）, respectively. The ratio of asymmetry in the absolute value of bilateral 45° deviation was 26.4% and the ratio of asymmetry in the absolute value of bilateral 90° deviation was 1.3%. ③The intra-class correlation coefficient（ICC） for 0°, L45°, R45°, L90° and R90° was 0.625, 0.641, 0.564, 0.769, 0.656, respectively. Conclusion:SVH has good test-retest reliability and high clinical test stability and stability. The data on normal values of SVH at different head tilt angles established in this study can provide clinical references for the refined diagnosis and functional assessment of vestibular system disorders.

Sensitization of Visually Induced Motion Sickness by Prior Provocative Physical Motion

INTRODUCTION: Habituation to motion has therapeutic applications for motion sickness desensitization and rehabilitation of patients with vestibular disease. Less attention has been devoted to the opposite process: sensitization. METHODS: Subjects (N = 50) were randomly allocated to four sequences: Baseline visual stimulus; then 15 min of time gap; cross-coupled motion (C-C) or a Control condition; then a time gap of 15 min or 2 h; then a retest visual stimulus. Motion exposures were for 10 min or until moderate nausea, whichever was sooner. The visual stimulus was a scene rotating in yaw at 0.2 Hz with superimposed "wobble". C-C was whole-body rotation on a turntable with eight 45° head tilts during each 30-s period. Control was head tilt without rotation. Rotational velocity was incremented in staircase steps of 3° · s−1 every 30 s. RESULTS: Groups were equivalent for Total Motion Sickness Symptom scores elicited by the first visual stimulus (combined: mean ± SD 10.8 ± 8.4). C-C produced greater Total Symptoms (20.3 ± 6.8) than Control (3.1 ± 3.7). Subjects recovered subjectively from C-C before retest of visual stimulus. For the retest visual stimulus, Total Symptoms were higher following C-C (15.1 ± 9.0) than following Control (8.3 ± 7.1) for both the 15 min and 2 h retests. Sickness ratings (SR) mirrored these effects of C-C. DISCUSSION: C-C motion sensitized subsequent responses to visual stimulation up to 2 h later. Sensitization of visual stimulation crossed modalities and appeared subconscious since it occurred despite subjective recovery from C-C. For some individuals, a previously relatively innocuous visual stimulus became nauseogenic on retest. The results have implications for the use of visual technologies within hours of exposure to provocative motion. Golding JF, Alund D, Gresty MA, Flynn MB. Sensitization of visually induced motion sickness by prior provocative physical motion. Aerosp Med Hum Perform. 2024; 95(10):741–748.

Functional Symmetry Observation Scale, Version 2: Reliability, Construct Validity, and Potential for Clinical Use.

To examine the intrarater and interrater reliability and construct validity of the Functional Symmetry Observation Scale, Version 2 (FSOS-V2) in infants with congenital muscular torticollis (CMT). The FSOS-V2 is a video-based measure of postural and movement symmetry in infants with CMT. Four examiners scored 50 participants' videos twice. Scores obtained by the same rater and across 4 raters were compared to examine intrarater and interrater reliability, respectively. Participants' habitual head deviation from midline in supine photographs was measured using a protractor. Relationship between the head tilt angles and FSOS-V2 scores was examined to assess construct validity. Fifty infants with CMT, age range 1 to 16months, participated. Results indicated moderate to good intrarater and poor to moderate interrater reliability. The FSOS-V2 construct validity was supported. The FSOS-V2 can be used by the same therapist repeatedly to make clinical decisions. Further research will strengthen its psychometric properties.

Coexistence of congenital superior rectus muscle fibrosis and Marcus Gunn jaw-winking phenomenon

A 6-year-old male involving a coexistence of congenital fibrosis of the superior rectus muscle (SR) with Marcus Gunn Jaw-Winking phenomenon presented with an elevation of the upper eyelid along with a chronically open mouth that had been present since early infancy. There was extropia and hypertropia, a limitation of elevation and depression in the right eye, and an abnormal head posture (AHP) with a left head tilt, right face turn, and a chin-up head position. He also displayed an upper eyelid retraction and a 2-mm lagophthalos in the right eye. Results of the forced duction test indicated a constricted SR of the right eye. A dissection of the SR from the levator palpebrae superioris and a 5-mm SR recession was performed within the right eye. At 2 months post surgery, there was a 3 prism diopters (PD) hypertropia in the right eye when the left eye was fixated on the target and a 10 PD hypotropia in the left eye when the right eye was fixated on the target, along with an improvement in his AHP. In this rare case with a coexistence of congenital fibrosis of the SR and Marcus Gunn jaw-winking phenomenon, we found that the performance of an individualized surgical protocol proved effective in reducing the vertical deviation and improving AHP.

Optimizing Corticosteroid Sinonasal Irrigation Outcomes Through 3D Printing: A Randomized Pilot Clinical Trial.

Topical corticosteroid irrigation plays critical role in the management of chronic rhinosinusitis (CRS). Yet, its efficacy can be highly variable. We sought to determine if personalized, 3-dimensional (3D)-printed nasal models can optimize head positioning and irrigation parameters, therefore improving patient outcomes. Randomized, single-blinded clinical trial. Tertiary medical center from November 2021 to July 2023. Sixty-two patients with CRS were randomized into either control (CG), backfill (BG), or model (MG) groups; daily 2 mg mometasone irrigations were then performed for 2 months with either standard head-forward and natural side-tilt position (CG), a head tilt of 90° to the side with fluid entering the lower nostril (BG), or in an optimized position as determined by a patient-specific 3D printed irrigation model (MG), respectively. A total of 36 patients completed the trial (CG: N = 14/23; BG N = 11/23, MG: N = 11/16). Significant posttreatment improvement in Lund-Mackay (LM) scoring was only observed in the MG (-3.73, 95% confidence interval = -5.71, -1.75; P < .001). Patient-reported outcome measures (Nasal Obstruction Symptom Evaluation, Sinonasal Outcome Test-22, and Visual Analog Scale of nasal congestion) improved significantly among all groups. Optimal model penetration scores significantly correlated to posttreatment MG LM score (Spearman's r = 0.65, P < .05). Among all groups, patients with prior endoscopic sinus surgery (ESS) (n = 19) had objectively less opacification at baseline; however, experienced the same degree of opacification reduction and symptom reduction as those without prior ESS (n = 17). The use of 3D printing to personalize head positioning may significantly improve objective corticosteroid irrigation outcomes. Mometasone irrigation may have similar subjective and objective effects on patients regardless of prior surgical history. Level 1 prospective, randomized, single-blinded clinical trial NCT06118554.

One- vs Two- vertical muscle surgery in the management of unilateral superior oblique muscle palsy with hypertropia over 20 PD

ABSTRACT Purpose: To compare the surgical outcomes of One- versus Two-vertical muscle surgery in patients with unilateral superior oblique muscle palsy (SOP) with primary position hypertropia (HT) over 20 PD. Patients in Group 1 underwent inferior oblique anterior transposition plus resection (IOATR), while patients in Group 2 underwent inferior oblique anterior transposition (IOAT) along with contralateral inferior rectus (IR) recession. Methods: Medical data of all SOP patients treated by either procedure from 2000 to 2023 in our strabismus center were recruited. We compared surgical outcomes between Group 1 and Group 2 by analyzing HT correction, rate of under-correction, and over-correction. Results: The study included 33 patients in Group 1 and 23 in Group 2. Both groups were similar in age, sex, etiology, affected side, diplopia, and head tilt. Group 2 achieved higher HT correction in all measured gazes. Group 1 had a higher risk of under-correction (18.18% in Group 1 vs 8.69% in Group 2) while Group 2 had a higher rate of over-correction (21.73% vs 0% in Group 1). Conclusion: In patients with severe unilateral SOP, Two-vertical muscle surgery achieved higher amounts of HT correction in all gazes despite a significantly higher risk of over-correction.

Visual impact of diffusion optic technology lenses for myopia control.

To assess the visual impact of Diffusion Optics Technology™ 0.2 DOT lenses (SightGlass Vision Inc.) designed for myopia control on primary gaze. DOT spectacle lenses contain light scattering elements that scatter light as it passes through the lens which, in turn, reduces retinal image contrast. Fifty-one children (12.2 ± 1.3, range 10-14 years; 51% females) were randomly assigned to wear DOT spectacle (n = 27) or single vision lenses (n = 24) across six investigational sites in North America. Binocular high- and low-contrast distant visual acuities, near visual acuity, reading speed, contrast sensitivity, stereoacuity and glare were assessed in primary gaze after at least 3 years of wear, with the study 95% powered in all metrics to detect significant differences between the groups. Mean binocular distance high-contrast (-0.09 ± 0.02 vs. -0.08 ± 0.02 logMAR, p = 0.81), low-contrast (0.05 ± 0.02 vs. 0.07 ± 0.02 logMAR, p = 0.52) and near visual acuity with glare sources (-0.06 ± 0.03 vs. -0.09 ± 0.03 logMAR, p = 0.32) were similar for DOT and single vision lens wearers, respectively. Contrast sensitivity was similar between children wearing DOT or single vision lenses across 11 of the 16 spatial frequencies (p > 0.05). Mean stereopsis was similar (p = 0.30) with the DOT lenses (33.2 ± 12.5″) and single vision lenses (38.1 ± 14.2″). Functional reading speed metrics were similar in both study groups, as was the objectively measured head tilt during reading (p > 0.05). The mean halo radius was 0.56° ± 0.17° with the DOT lenses compared with 0.50° ± 0.12° with single vision lenses (p = 0.02), but the statistically significant difference was smaller than the non-inferiority bound of 0.4°. Diffusion optics technology lenses provide a clinically equivalent visual experience to a standard single vision lens.

Clinical outcome of cats with suppurative otitis media and intact tympanum submitted to myringotomy: retrospective findings from 26 cases.

The efficacy of medical treatment associated with single myringotomy in cats with suppurative otitis media (OM) and intact tympanum was retrospectively evaluated. Patients' records were retrieved from cats with suppurative OM. Cats were included in this retrospective study based on fluid content within the tympanic cavity on imaging, intact tympanum on otoendoscopic examination and neutrophils on ear bulla exudate cytological examination. A total of 26 cats with middle ear suppurative otitis were included. Just over half of the cats (54%) presented bilateral involvement. Clinical signs included head tilt (13/26), otalgia (9/26), Horner's syndrome (7/26), external ear discharge (5/26), and nystagmus and facial paralysis (1/26). Cocci were identified on cytological examination in 18/40 samples and rods in 2/40. Bacterial culture results were positive in 15/40 samples, with Pseudomonas species (4/15), Pasteurella multocida (3/15), Staphylococcus felis (3/15), Staphylococcus schleiferi (2/15), Staphylococcus canis (2/15), Escherichia coli (2/15), Staphylococcus pseudintermedius (1/15) and Serratia marcesens (1/15) isolation. After myringotomy and gentle flushing of middle ear bullae (0.5-2 ml saline per ear), all cats were treated with oral corticosteroids and a 1-month course of systemic antibiotics according to sensitivity testing. In total, 19 (73%) cats were clinically healed 60-240 days after treatment. One cat was euthanased because of failure to eradicate a Pseudomonas species infection. Another cat died a few hours after the procedure. The five remaining cats were cured after ventral bulla osteotomy. OM without an aural polyp is a frequent diagnosis in cats, but data on medical treatment are scarce. This simple therapeutic technique, single myringotomy procedure and mild ear flushing, offers a practical, safe and efficient first-line treatment of suppurative OM with an intact tympanum in cats with or without neurological signs.

Posterior-only approach cervical hemivertebrectomy and short fusion with pedicle screws in young children with cervical scoliosis: case report and technical note.

Cervical hemivertebrae (C3-6) causing significant osseous torticollis, head tilt and facial asymmetry are rare and complicated. Cervical hemivertebrectomy (CHVE) by a posterior-only approach was never reported because it is highly risky and its efficacy remains controversial. This study is to evaluate the feasibility and preliminary clinical outcomes of posterior-only approach for CHVE and torticollis correction in young children. Four young children aged 5-9 years old with significant torticollis caused by cervical hemivertebrae underwent deformity correction consisting of cervical pedicle screw (CPS) placement with O-arm-based intraoperative navigation, CHVE using ultrasonic bone scalpel and short-segmental posterior instrumentation and fusion. Details of this novel technique were presented. The preliminary short-term clinical and radiographic outcomes were assessed. On average, the operative time was 312.5 ± 49.9min, and the surgical blood loss was 375.0 ± 150.0ml. The structural cervical scoliosis was corrected from 31.5 ± 7.3° to 11.0 ± 4.1°, and the average correction rate was 64.9%. Head tilt was favorably corrected from 11.0 ± 4.2° to 3.5 ± 2.6°. The shoulder balance improved from 6.3 ± 1.3° to 1.5 ± 1.9°. One case with C6 CHVE had convex side radiating nerve root pain but no sign of muscle power weakness. Full recovery was achieved one month after surgery. No other complication occurred. CHVE by a posterior-only approach was a feasible alternative option for the treatment of congenital cervical scoliosis. It could resect the CHV effectively and achieve satisfactory torticollis correction without additional anterior access surgery. Successful CPS placement in this child population was essentially important to enable reliable osteotomy closure and firm posterior instrumentation.

Clinical and magnetic resonance imaging features of unilateral thalamic porencephaly in a dog

AbstractA 1‐year‐3‐month‐old, female, neutered labrador retriever was presented with a history of circling behaviour since 2 months of age and a recently detected blindness affecting its right eye. Neurological examination revealed a left‐sided head tilt, compulsive tight circling towards the left, postural reaction deficits in the right thoracic and pelvic limbs, absent menace response in the right eye and ventral positional strabismus of the left eye. The neurological examination findings were localised to the left thalamus. Magnetic resonance imaging of the head revealed porencephaly involving the left dorsal aspect of the thalamus. Furthermore, reduced volume of the left rostral colliculus, crus cerebri and optic chiasm, alongside marked thinning of the left cerebral hemispheric white matter tracts with associated left lateral ventriculomegaly, were present. Based on magnetic resonance imaging features and clinical history, a congenital or perinatal encephaloclastic porencephaly with secondary hypoplasia or atrophy of the associated thalamic projection pathways was prioritised.

Investigation of Video Ocular Counter-Roll Findings According to Head and Body Tilt Positions in Healthy Subjects.

A vestibulo-ocular reflex called the ocular counter-roll can be used to assess how well the otolith organs are functioning. The video ocular counter-roll (vOCR) test is a recent addition to the videonystagmography test battery that allows for video recording and quantitative ocular counter-roll analysis. The purpose of this study is to investigate potential discrepancies in vOCR measurements obtained from a 30° lateral head tilt in the roll plane versus measurements obtained from a 30° tilt of the head and body. Thirty otologically, and neurologically healthy subjects aged 18 to 30 (M = 23.32 years, SD = 2.66 years; 8 men, 22 women) participated in this study. Pure-tone audiometry, oculomotor tests, and vOCR evaluation were performed for all participants. The vOCR assessment was performed in 2 positions, 30° lateral head tilt, and 30° body tilt position. The degree of static vOCR eye position and vOCR asymmetry in both positions were calculated and compared. There was no statistically significant difference between the vOCR findings obtained in the right and left 30° lateral head tilt (p = 0.546) and body tilt (p = 0.114). vOCR asymmetry was determined as median (interquartile range) 0.08 (0.07) in lateral head tilt position and 0.09 (0.06) in body tilt position. The degree of static vOCR (8.75° [1.91]) detected during body tilt was statistically greater than the static vOCR (6.62 [1.69]) detected during head tilt (p < 0.001). There was no statistically significant difference in terms of ocular counter-roll asymmetry detected between head tilt and body tilt (p = 0.918). Our study shows a significant difference in the vOCR responses during head tilt and body tilt, a finding that should be considered during clinical evaluation of vestibular function. There was no significant asymmetry between the responses with either head or body tilt.

Variations in head tilt during the acquisition of CBCT scans and their effects on effective radiation dose.

This study evaluated the impact of variations in anteroposterior and lateral tilts of patients' head on radiation-weighted doses to organs/tissues and effective doses using three different cone beam computed tomography machines. An anthropomorphic phantom was used to estimate radiation doses in three CBCT machines (OP300, Eagle X 3D, and Eagle Edge). Thermoluminescent dosimeters were placed in regions corresponding to pre-stablished organ/tissues. CBCT examinations from the posterior mandible and anterior maxilla regions were acquired, with three different anteroposterior angulations (0°, 30°, and 45°), and from the posterior mandible in three different lateral angulations (0°, 20° to the left, and 20° to the right side). Radiation-weighted doses for each organ/tissue and effective doses were calculated for each machine and angulation. For the posterior mandible acquisitions, anteroposterior angulations of the head at 30° and 45° yielded a reduction in effective doses in all three devices. A 20° tilt to the right side resulted in lower doses than to the left (same side as the FOV). For the anterior maxilla, increased anteroposterior angulation was associated with reduction in effective dose in two devices. Effective doses are lower when small FOV CBCT exams of the posterior mandible and anterior maxilla are acquired with increased anteroposterior head angulation at 30° and 45°. For FOV in the posterior mandible, a 20° lateral tilt towards the side opposite to the FOV also yields lower effective doses. The main contribution to these dose reductions is the decrease in dose to salivary glands.

Comprehensive comparative study ofChiari-like malformation inveterinary and human medicine.

This review aims toenrich our understanding ofChiari-like malformation (CLM) bycombining human and veterinary insights, and providing adetailed cross-species overview. CLM isadevelopmental abnormality characterised bycaudal displacement ofthe hindbrain into the foramen magnum due toan entire brain parenchymal shift caused byinsufficient skull volume. This malformation leads toaprogressive obstruction atthe craniocervical junction, which disrupts the normal cerebrospinal fluid flow, leading tosecondary syringomyelia. The clinical signs ofCLM and syringomyelia include phantom scratching, head tilt, head tremor, ataxia, tetraparesis, pain, muscle atrophy, and scoliosis ortorticollis. Magnetic resonance imaging remains the gold standard for diagnosing CLM, since itallows the visualisation ofabnormal findings such asthe caudal cerebellar herniation, caudal cerebellar compression from occipital dysplasia, and attenuated cerebrospinal fluid cisternae. Although various medical and surgical interventions, including foramen magnum decompression, can provide temporary symptomatic/clinical sign relief, current literature shows alack ofsustained long-term efficacy. Therefore, additional research isneeded toevaluate the long-term effects ofexisting treatment strategies and tocompare different techniques utilised inconjunction with foramen magnum decompression.

Human proprioceptive gaze stabilization during passive body rotations underneath a fixed head

The present study explored the presence of torsional gaze-stabilization to proprioceptive neck activation in humans. Thirteen healthy subjects (6 female, mean age 25) were exposed to passive body rotations while maintaining a head-fixed, gravitationally upright, position. Participants were seated in a mechanical sled, their heads placed in a chin rest embedded in a wooden beam while wearing an eye tracker attached to the beam using strong rubber bands to ensure head stability. The body was passively rotated underneath the head both in darkness and while viewing a projected visual scene. Static torsional gaze positions were compared between the baseline position prior to the stimulation, and immediately after the final body tilt had been reached. Results showed that passive neck flexion produced ocular torsion when combined with a visual background. The eyes exhibited rotations in the opposite direction of the neck’s extension, matching a hypothetical head tilt in the same direction as the sled. This corresponded with a predicted head rotation aimed at straightening the head in relation to the body. No such response was seen during trials in darkness. Altogether, these findings suggest that proprioception may produce a predictive gaze-stabilizing response in humans.