Changes In Head Position Research Articles

Hood Nebulization: Effects of Head Direction and Breathing Mode on Particle Inhalability and Deposition in a 7-Month-Old Infant Model

Aerosol drug delivery to infants is a strong function of their behavior. Infants can be active during medication administration, changing head position or breathing mode. The objective was to evaluate the influence of the head direction and breathing mode on the hood drug delivery in a 7-month-old girl airway model by using an approach that couples imaging with computational fluid dynamics (CFD). Three head directions, i.e., face up, face side, and sitting (face front), and two breathing modes, i.e., oronasal and nasal breathing, were studied. The face-airway model was developed from computed tomography scans of a 7-month-old girl. Respiratory airflows and particle transport were simulated with the low Reynolds number κ-ω turbulence model and Lagrangian tracking approach. Three pharmaceutical aerosol sizes (1, 2.5, and 5 μm) via hood nebulization were considered under quiet breathing conditions (5 L/min). Both head direction and breathing mode can noticeably affect aerosol inhalability and lung delivery efficiency. A maximum of 20% difference in inhalability is observed among the three head positions. Facial-ocular depositions are predominantly influenced by head position, but not breathing mode. The facial-ocular deposition rate with the face-up position is about threefold that with the sitting position for 5-μm particles. Nasal breathing gives about 17.8% lower lung deposition and about 65% higher facial-ocular deposition than the oronasal breathing. The face-side position has less facial-ocular deposition than the face-up position, while still achieving similar lung delivery efficiency. Because aerosols deposited around the eyes may cause irritation to the eyes, the face-side position appears to be a better option than the face-up position for comfort and safety reasons.

Immediate Changes in Masticatory Mechanosensitivity, Mouth Opening, and Head Posture After Myofascial Techniques in Pain-Free Healthy Participants: A Randomized Controlled Trial

ObjectiveThis study aimed to assess the immediate effects on masticatory muscle mechanosensitivity, maximal vertical mouth opening (VMO), and head posture in pain-free healthy participants after intervention with myofascial treatment in the temporalis and masseter muscles. MethodsA randomized, double-blind study was conducted. The sample group included 48 participants (n = 48), with a mean age of 21 ± 2.47 years (18-29). Two subgroups were defined: an intervention group (n = 24), who underwent a fascial induction protocol in the masseter and temporalis muscles, and a control group (n = 24), who underwent a sham (placebo) intervention. The pressure pain threshold in 2 locations in the masseter (M1, M2) and temporalis (T1, T2) muscles, maximal VMO, and head posture, by means of the craniovertebral angle, were all measured. ResultsSignificant improvements were observed in the intragroup comparison in the intervention group for the craniovertebral angle with the participant in seated (P < .001; F1,23 = 16.45, R2 = 0.41) and standing positions (P = .012, F1,23 = 7.49, R2 = 0.24) and for the pressure pain threshold in the masticatory muscles, except for M2 (P = .151; M1: P = .003; F1,23 = 11.34, R2 = 0.33; T1: P = .013, F1,23 = 7.25, R2 = 0.23; T2: P = .019, F1,23 = 6.41, R2 = 0.21). There were no intragroup differences for the VMO (P = .542). Nevertheless, no significant differences were observed in the intergroup analysis in any of the studied variables (P > .05). ConclusionMyofascial induction techniques in the masseter and temporalis muscles show no significant differences in maximal VMO, in the mechanical sensitivity of the masticatory muscles, and in head posture in comparison with a placebo intervention in which the therapist's hands are placed in the temporomandibular joint region without exerting any therapeutic pressure.

Cell-by-Cell Alignment of Repeated Specular Microscopy Images from the Same Eye

PurposeModern specular microscopes (SM) robustly depict the same central area of the corneal endothelium at different time points through a built-in fixation light. However, repeated image acquisitions slightly shift and rotate because of minute changes in head position in the chin and forehead rest. This prevents the manual retrieval of individual corneal endothelial cells (CECs) in repeated measurements because SM images usually lack obvious landmarks. We devised and validated an image registration algorithm that aligns SM images from the same eye to make corresponding CECs coincide.MethodsWe retrospectively selected 27 image pairs for the presence of significant image overlap. Each image pair had been recorded on the same day and of the same eye. We applied our registration method in each image pair. Two observers independently validated, by means of alternation flicker, that the image pairs had been correctly aligned. We also repeatedly applied our registration method on unrelated image pairs by randomly drawing images and making certain that the images did not originate from the same eye. This was done to assess the specifity of our method.ResultsAll automated registrations of the same-day and same-eye image pairs were accurate. However, one single image incorrectly failed to trigger the non-match diagnosis twice in 81 registration attempts between unrelated images. As it turned out, this particular image depicted only 73 CECs. The average number of CECs was 253 (range 73–393).ConclusionRepeated non-contact SM images can be automatedly aligned so that the corresponding CECs coincide. Any successful alignment can be considered as proof of the retrieval of identical CECs as soon as at least 100 CEC centroids have been identified. We believe our method is the first to robustly confirm endothelial stability in individual eyes.

Hypopyon as the first sign of relapse in acute lymphoblastic leukaemia

Ocular localizations ranging from leukemic retinopathy to involvement of the iris and anterior chamber may be observed as clinical manifestations of acute lymphoblastic leukaemia (ALL). Involvement of the anterior ocular segment is very rare in adult ALL, and is found in less than 1 % of leukaemic relapses [1, 2]. We report a case of leukemic hypopyon, secondary to sedimentation of leukemic blast cells in the ocular anterior chamber, occurring in a 62-year-old woman with T-ALL who was treated with the induction chemotherapy including methotrexate, cytarabine, cyclophosphamide, doxorubicin, vincristine, and dexamethasone, also with a central nervous system (CNS) prophylaxis, and achieved a complete remission. Fourteen months after the first complete remission, while receiving maintenance therapy (mercaptopurine and methotrexate), the patient complained of an ipsilateral reduction of visual acuity on the left associated with changes in head position. Ophthalmic evaluation was performed, showing a leukemic hypopyon with a horizontal fluid level (measuring 3 mm) in the left eye. The patient refused anterior chamber paracentesis. A lumbar puncture revealed CNS relapse with 50 blast cells/lL of cerebrospinal fluid (CSF). The lymphoid blasts were positive for CD7, CD5, CD2, and CD13. Although the patient was treated with intrathecal chemotherapy with methotrexate and cytarabine, and later with liposomal cytarabine, with a clearing of malignant cells from the CSF, a worsening of the anterior chamber hypopyon was noted and the patient required ocular radiotherapy with a transient and partial response. The patient died (7 months after the diagnosis of hypopyon) with ocular, cutaneous, and bone marrow leukemic involvement.

Time Course Analysis of Influence of Food Hardness on Head Posture and Pitching of Head during Masticatory Movement

The purpose of the present study was to investigate the relationship between mastication and head posture using foods with different degrees of hardness. A total of 12 healthy, dentulous volunteers participated in the study. Each participant was required to chew two types of gummy candy with two levels of hardness while sitting upright. Measurements were conducted using an optoelectric jaw-tracking system with 6 degrees of freedom (Gnatho-Hexagraph II JM-2000®). The horizontal plane perpendicular to the direction of gravitational force served as the reference plane. Analysis of the gradient of the Frankfurt plane (head posture) and pitching of the head during masticatory movement was conducted. The influence of the type of test food on these parameters was evaluated during mastication. During stable mastication, the gradient of the Frankfurt plane was 4.66 degrees on average, close to the horizontal plane. The time course of the Frankfurt plane gradient revealed a tendency toward dorsal flexion during the first to middle phases of mastication, and a tendency toward ventral flexion during the middle to last phases, regardless of the hardness of the test food. The participants were divided into two groups based on change in head posture during chewing. The results showed while there was no change in head posture in the group with marked pitching of the head, head posture did change in the group with little pitching.

Bilateral Cerebellar Infarcts from Vertebral Artery Insufficiency Caused by Cervical Osteophytes

Abstract Background: In previous reports, the patients are described to have transient symptoms from physiologic rotation or extension of the cervical spine, resulting from a cervical osteophyte compressing the vertebral artery and causing vertebral artery insufficiency, known as Bow Hunter syndrome. Methods: An 85-year-old female presented with new onset occipital headaches, nausea, vomiting and vertigo that were not precipitated by change in head position. Patient had bilateral cerebellar infracts. Patient underwent decompression and instrumented stabilization of the cervical spine from the posterior approach. Results: At one-year follow-up, patient remained stroke free with patent vertebral artery. Conclusion: To our knowledge, this is the first report of bilateral infraction from a vertebral artery insufficiency caused by cervical osteophytes without history of transient symptoms from movement of the head or neck, a variant of the Bow Hunter syndrome. Anterior versus posterior approach for vertebral artery insufficiency from osteophytic compression should be primarily based on location of the pathology and not the cervical level of involvement.

音響テレプレゼンスロボットの聴覚実験における有用性

“Embodiment” plays a critical role in robots' learning, human-robot interaction, and understanding of environment for robots. The concept is also important for the research of robot audition and human auditory perception. We devised an acoustical telepresence robot, “TeleHead” that has a user-like dummy head and can be synchronized with user's head movement. We performed several psychophysical experiments to assess sound localization, delay discrimination, and auditory perceptual grouping ability in humans. The errors of the sound localization via TeleHead were less than 10[deg]. Head posture change during the discriminable delay time ranged from 10[deg] to 17[deg]. The performance of auditory perceptual grouping did not differ between conditions with and without TeleHead. In addition, we used TeleHead to divide head movement effects on perception into three factors: self-movement, sound source movement, and acoustical change. The results indicate that TeleHead can mirror the 3D motion of users with minimal latency and distortion, suggesting that it is a useful tool for measurements of human auditory perception.

Evaluating the head posture of dentists with no neck pain

Dentistry is one of the professions that requires a high degree of concentration during the treatment of patients. There are many predisposing factors, affecting dentists when working on the patient's teeth, including neck flexion, arm abduction and inflexible postural positions, which may put them at the risk of developing musculoskeletal disorders related to the neck. Although dentists with long records of service show different levels of pain and discomfort in their necks, there is no evidence regarding whether younger dentists report neck pain before the onset of an abnormal condition in this region, including forward head posture (FHP). Discovering any alteration in the head posture of dentists might confirm one of the reasons for neck pain in this population. Forty one dentists with no neck pain and forty controls having jobs other than dentistry who had no risk factors related to head posture voluntarily participated in the present study. A standard method was used to measure the cervical curve in these two groups. There was no significant difference between the mean values of cervical curve in dentists and the control group (p > 0.05). There was also no significant difference between cervical curve values in dentists working for either 5-8 years or 8-12 years (p > 0.05). The only significant difference was observed in mean cervical curve values of men and women in the dentist group (p < 0.05). No alteration of cervical curve in the dentist group compared to controls might be due to absence of pain sensation in the dentists in the current study. In other words, this group might have not yet experienced sufficient change in head posture to experience significant pain in their neck region.

A Computerized Photographic Method to Evaluate Changes in Head Posture and Scapular Position Following Rapid Palatal Expansion: A Pilot Study

To assess the applicability of a computerized method to measure on digital photographs the changes in head and scapular posture following rapid palatal expansion (RPE) treatment. Randomized controlled trial. Twenty-three children (age 9.2 +/- 70.88 years) diagnosed with maxillary constriction were randomly divided into two groups: 1. Study group (n = 12): patients receiving RPE treatment; 2. Untreated controls (n = 11). Postural measurements were taken on frontal, lateral, and dorsal views of each subject. In the study group measurements were taken at T0 (the day orthodontic records were taken), T1 (end of RPE active phase), and T2 (RPE removal). In controls the same observations were conducted at T0 and T1(98.18 +/- 36.01 days after T0). Measurements were statistically analyzed (Intraclass Correlation Coefficient, t-tests, Signed Rank test, One-Way Repeated Measures Analysis of Variance, Tukey test; p < 0.05). In the study group a significant reduction in forward head posture (FHP) occurred between T0 and T1. Forward shoulder posture (FSP) decreased significantly between T1 and T2. At T1 treated patients exhibited significantly lower values of the measurements indicating FHP and FSP than controls. Changes in head and scapular posture following RPE treatment can be documented with computerized measurements on digital photographs.

Effect of low pull headgear on head position

To evaluate changes in head position following the use of low pull headgear (LHG) and compare these changes with an untreated control group. The test group comprised pre-treatment and post-treatment lateral cephalograms of 30 males, aged 11±1.5years, who were receiving LHG therapy for correction of Class II malocclusion. Pre-observation and post-observation lateral cephalograms of 25 untreated male subjects, aged 11±1.6years, served as controls. The average treatment time for the treatment group was 12±2.02months and the average observation period for the control group was 11±1.03months. Four postural variables (NSL/CVT, NSL/OPT, CVT/HOR, OPT/HOR) were measured to evaluate the head position in all subjects pre- and post-observations. There was no significant difference in all the measurements concerning the head position within each group (p>0.05). The mean differences of pre- and post-observations of 4 postural variables in the LHG group were 1.43, 0.9, -1.13, and -1.08, while those of the control group were 1.56, -0.32, -0.24, and 0.04, respectively. There was no significant difference between the headgear and control groups for any of the postural variables measured (p=0.924, 0.338, 0.448, and 0.398, respectively). Although postural variables showed considerable variability in both groups, head position exhibited no significant changes over a period of 11-12months either in the control or headgear group.

Positional Dizziness

This article reviews the most common conditions that are caused by changes in head or body positions. Practical clinical methods to help distinguish vestibular from nonvestibular and central from peripheral vestibular positional dizziness are discussed. This article also reviews the treatment methods of selected canal variants of benign paroxysmal positional vertigo (BPPV). Two recent evidence-based guidelines have established canalith repositioning maneuvers (Epley and Semont maneuvers) as safe and highly effective in the treatment of posterior canal BPPV. Recent studies suggest the Gufoni and the Lempert roll (barbecue) maneuvers are effective in treating lateral canal forms of BPPV. Most cases of positional vertigo are of peripheral vestibular origin and can be effectively treated by simple positioning maneuvers. This article reviews the variants of BPPV encountered in clinical practice, including mechanistic cause, differential diagnosis, prognosis, and treatment. Generous use of figures is intended to aid in understanding the most effective treatment maneuver techniques for the more common forms of BPPV. Clinicians who can recognize the types of nystagmus associated with the various canal types of BPPV can usually recognize CNS causes as distinct.

골프 드라이버 스윙 시 의도적인 구질 변화에 따른 운동학적 분석

The purpose of This study's aim is to examine the difference in the changes of body segment movement, variables for ball quality, and carry at golf driver swing according to the ball quality using comparative analysis. Regarding the impact variables according to the ball quality using the track man and carry, club speed was the fastest at draw shot, ball speed was the fastest at straight shot, and smash factor was the lowest at draw shot. About the vertical launch angle, the fade shot showed the highest launch angle while the max height of the ground and ball was the highest at fade shot. And carry was the longest at draw shot. For the flight time, it was the longest at draw shot. The landing angle was the largest at fade shot. About the club head position change and trajectory, at the overall event point, the fade shot drew a more outer trajectory at the point of the follow through(E6) than the straight or draw shot. Regarding the angular speed of shoulder rotation, at the overall event point, the fade shot showed the greatest angular speed change in the follow through(E6). Also, about the angular speed of pelvic rotation, at the overall event point, the draw shot showed the greatest angular speed change at the point of down swing(E4). Concerning the stance angle change, both straight and fade shots were open as the concept of open stance whereas the draw shot was close as that of close stance. Regarding the previous study, the most important factor of deciding Ball Quality is the club face angle's open and close state at Impact. In short, the Ball Quality and carry were decided by this factor.

Dynamic transformation of vestibular signals for orientation

The same pattern of vestibular afferent feedback may signify a loss of balance or a change in body orientation, depending upon the initial head posture. To resolve this ambiguity and generate an appropriate motor response, the CNS must transform vestibular information from a head-centred reference frame into relevant motor coordinates. But what if the reference frame is continuously moving? Here, we ask if this neural transformation process is continuously updated during a voluntary change in head posture. Galvanic vestibular stimulation (GVS) was used to induce a sensation of head roll motion in blindfolded subjects marching on the spot. When head orientation was fixed, this caused unconscious turning behaviour that was maximal during neck flexion, minimal with the head level and reversed direction with neck extension. Subjects were then asked to produce a continuous voluntary change in head pitch, while GVS was applied. As the neck moved from full flexion into extension, turn velocity was continuously modulated and even reversed direction, reflecting the pattern observed during the head-fixed condition. Hence, an identical vestibular input resulted in motor output which was dynamically modulated by changes in head pitch. However, response magnitude was significantly reduced, suggesting possible suppression of vestibular input during voluntary head movement. Nevertheless, these results show that the CNS continuously reinterprets vestibular exafference to account for ongoing voluntary changes in head posture. This may explain why the head can be moved freely without losing the sense of balance and orientation.

The effect of a cervical collar on the seal pressure of the LMA Supreme™: a prospective, crossover trial

For personnel inexperienced in airway management, supraglottic airway devices may be the first choice in an emergency. Changing head position is known to reduce the seal pressure of a laryngeal mask airway. The aim of this study was to investigate whether the use of a cervical collar improves the stability of airways secured with the LMA Supreme™ (The Laryngeal Mask Company Limited, Mahé, Seychelles). In this crossover trial, the primary endpoint was the difference in the seal pressure of the LMA Supreme in anaesthetised patients in maximum passive extension of the neck, with and without a cervical collar. The median (IQR [range]) seal pressure was 18 (13.8-22.1 [0-30]) cmH(2) O in maximum passive extension without a cervical collar. With a cervical collar in place, the seal pressure increased to 28 (22.8-30 [17-30]) cmH(2) O (p<0.001). In the neutral head position, the seal pressure was 22 (17.6-24.5 [12-30]) cmH(2) O without and 27 (22-30 [12-30]) cmH(2) O with a cervical collar in place (p<0.001). We found that a cervical collar stabilises the airway with an LMA Supreme in place and we recommend this combination for (pre-hospital) emergency cases.

The Tangential Nucleus Controls a Gravito-inertial Vestibulo-ocular Reflex

Although adult vertebrates sense changes in head position by using two classes of accelerometer, at larval stages zebrafish lack functional semicircular canals and rely exclusively on their otolithic organs to transduce vestibular information. Despite this limitation, we find that larval zebrafish perform an effective vestibulo-ocular reflex (VOR) that serves to stabilize gaze in response to pitch and roll tilts. By using single-cell electroporations and targeted laser ablations, we identified a specific class of central vestibular neurons, located in the tangential nucleus, that are essential for the utricle-dependent VOR. Tangential nucleus neurons project contralaterally to extraocular motoneurons and in addition to multiple sites within the reticulospinal complex. We propose that tangential neurons function as a broadband inertial accelerometer, processing utricular acceleration signals to control the activity of extraocular and postural neurons, thus completing a fundamental three-neuron circuit responsible for gaze stabilization.

Modifications of the Epley (canalith repositioning) manoeuvre for posterior canal benign paroxysmal positional vertigo (BPPV)

Benign paroxsymal positional vertigo (BPPV) is a syndrome characterised by short-lived episodes of vertigo associated with rapid changes in head position. It is a common cause of vertigo presenting to primary care and specialist otolaryngology (ENT) clinics. BPPV of the posterior canal is a specific type of BPPV for which the Epley (canalith repositioning) manoeuvre is a verified treatment. A range of modifications of the Epley manoeuvre are used in clinical practice, including post-Epley vestibular exercises and post-Epley postural restrictions. To assess whether the various modifications of the Epley manoeuvre for posterior canal BPPV enhance its efficacy in clinical practice. We searched the Cochrane ENT Group Trials Register; the Cochrane Central Register of Controlled Trials (CENTRAL); PubMed; EMBASE; CINAHL; Web of Science; BIOSIS Previews; Cambridge Scientific Abstracts; ICTRP and additional sources for published and unpublished trials. The date of the search was 15 December 2011. Randomised controlled trials of modifications of the Epley manoeuvre versus a standard Epley manoeuvre as a control in adults with posterior canal BPPV diagnosed with a positive Dix-Hallpike test. Specific modifications sought were: application of vibration/oscillation to the mastoid region, vestibular rehabilitation exercises, additional steps in the Epley manoeuvre and post-treatment instructions relating to movement restriction. Two authors independently selected studies from the search results and the third author reviewed and resolved any disagreement. Two authors independently extracted data from the studies using standardised data forms. All authors independently assessed the trials for risk of bias. The review includes 11 trials involving 855 participants. A total of nine studies used post-Epley postural restrictions as their modification of the Epley manoeuvre. There was no evidence of a difference in the results for post-treatment vertigo intensity or subjective assessment of improvement in individual or pooled data. All nine trials included the conversion of a positive to a negative Dix-Hallpike test as an outcome measure. Pooled data identified a significant difference from the addition of postural restrictions in the frequency of Dix-Hallpike conversion when compared to the Epley manoeuvre alone. In the experimental group 88.7% (220 out of 248) patients versus 78.2% (219 out of 280) in the control group converted from a positive to negative Dix-Hallpike test (risk ratio (RR) 1.13, 95% confidence interval (CI) 1.05 to 1.22, P = 0.002). No serious adverse effects were reported, however three studies reported minor complications such as neck stiffness, horizontal BPPV, dizziness and disequilibrium in some patients.There was no evidence of benefit of mastoid oscillation applied during the Epley manoeuvre, or of additional steps in the Epley manoeuvre. No adverse effects were reported. There is evidence supporting a statistically significant effect of post-Epley postural restrictions in comparison to the Epley manoeuvre alone. However, it important to note that this statistically significant effect only highlights a small improvement in treatment efficacy. An Epley manoeuvre alone is effective in just under 80% of patients with typical BPPV. The additional intervention of postural restrictions has a number needed to treat (NNT) of 10. The addition of postural restrictions does not expose the majority of patients to risk of harm, does not pose a major inconvenience, and can be routinely discussed and advised. Specific patients who experience discomfort due to wearing a cervical collar and inconvenience in sleeping upright may be treated with the Epley manoeuvre alone and still expect to be cured in most instances.There is insufficient evidence to support the routine application of mastoid oscillation during the Epley manoeuvre, or additional steps in an 'augmented' Epley manoeuvre. Neither treatment is associated with adverse outcomes. Further studies should employ a rigorous randomisation technique, blinded outcome assessment, a post-treatment Dix-Hallpike test as an outcome measure and longer-term follow-up of patients.

Forehead pressure sore following a prolonged operation and the role of the Mayfield head frame in re-operation

To the Editor: Appropriate intraoperative patient positioning by surgeons and anaesthetists is essential to prevent pressure sores. Facial pressure sores are rare, and their occurrence is possibly underreported [1]. We report a unique case of a stage 2 forehead pressure sore developing after a 21-h operation in the prone position despite full anesthetic precautions, and we advocate use of the Mayfield head frame to prevent deterioration if re-operation is required in the prone position in such scenarios. A 43-year-old overweight gentleman with sacral chondrosarcoma and no other significant medical history underwent hemisacrectomy and two-stage reconstruction with a free latissimus dorsi musculo-osseo-cutaneous flap. He was intubated and lay in the prone position for the duration of the second-stage reconstruction. He was placed on a cami table, with full padding precautions and a head ring. The total duration of the operation was 21 h. Postoperatively the patient was noted to have a 4 9 2 cm grade 2 forehead pressure ulcer (Fig. 1). The patient returned to the operating room for an exploration of the free flap following an absent venous Doppler signal, although clinically the flap appeared viable. On this occasion he was placed in a Mayfield head frame to avoid further pressure on his forehead sore. Intraoperatively the flap was indeed viable, but the internal venous Doppler revealed it required repositioning. This procedure took 2 h. The forehead pressure sore was unchanged postoperatively as a result of the avoidance of pressure on it and the shorter operative period. It was subsequently treated conservatively with regular dressings and healed 2 months later. In our case, the Mayfield head frame was utilized when the patient was taken back to the operating room for flap exploration in the prone position to avoid further facial tissue compromise. This frame is generally used for head stabilization during intracranial surgery. However, there have been reports of hematomas following its use if placed against anatomically thin bone (such as the squamous part of the temporal bone) or pathologically thin bone (as can happen after chronic intracranial hypertension) [2, 3]. Goodwin et al. [4] believe the use of the head frame prevents the development of facial pressure sores in patients undergoing sacrectomy. Facial pressure sores can cause much physical and emotional morbidity, adding to the already appreciable healthcare costs of treating these patients. As the number of prone cases in surgery increases, it is crucial to recognize all patients at risk and to address all contributory factors, particularly if prolonged procedures are anticipated. Established methods to reduce facial pressure sore development include widening of the facial–pillow contact area to disperse the pressure, checking facial skin status frequently, and changing head position regularly (when the H. Sadideen (&) H. Giele Department of Plastic and Reconstructive Surgery, West Wing, John Radcliffe Hospital, Oxford, UK e-mail: hazim.sadideen@doctors.org.uk

A Case of Cerebellar Hemangioblastoma Mimicking Benign Paroxysmal Positional Vertigo

Received September 22, 2011 Revised November 18, 2011 Accepted November 29, 2011 Address for correspondence Hyun Seung Choi, MD Department of OtolaryngologyHead and Neck Surgery, National Health Insurance Corporation Ilsan Hospital, 100 Ilsan-ro, Ilsandong-gu, Goyang 410-719, Korea Tel +82-31-900-0972 Fax +82-31-900-0613 E-mail choihyunseung@gmail.com The most common cause of positional vertigo is benign paroxysmal positional vertigo (BPPV). BPPV is characterized by brief recurrent spells of vertigo often brought about by certain head position changes that occur when looking up, turning over in bed, or straightening up after bending over. Its diagnosis relies on a thorough history and physical examination, including Dix-Hallpike maneuver. BPPV usually resolves spontaneously, but treatment of persistent cases with canalolith repositioning maneuvers and exercise therapy has been relatively successful. Those patients with atypical findings or whose symptoms fail to respond to medical therapy and otolith repositioning maneuver, however, require further evaluation to rule out intracranial pathologic conditions. We report here on an unusual case of cerebellar hemangioblatoma showing paroxysmal positional vertigo with a review of the related literature. Korean J Otorhinolaryngol-Head Neck Surg 2012;55:58-61 Key WordsZZPositional vertigo ᆞPositional nystagmus ᆞHemangioblastoma.

Fos expression in neurons of the rat vestibulo-autonomic pathway activated by sinusoidal galvanic vestibular stimulation.

The vestibular system sends projections to brainstem autonomic nuclei that modulate heart rate and blood pressure in response to changes in head and body position with regard to gravity. Consistent with this, binaural sinusoidally modulated galvanic vestibular stimulation (sGVS) in humans causes vasoconstriction in the legs, while low frequency (0.02–0.04 Hz) sGVS causes a rapid drop in heart rate and blood pressure in anesthetized rats. We have hypothesized that these responses occur through activation of vestibulo-sympathetic pathways. In the present study, c-Fos protein expression was examined in neurons of the vestibular nuclei and rostral ventrolateral medullary region (RVLM) that were activated by low frequency sGVS. We found c-Fos-labeled neurons in the spinal, medial, and superior vestibular nuclei (SpVN, MVN, and SVN, respectively) and the parasolitary nucleus. The highest density of c-Fos-positive vestibular nuclear neurons was observed in MVN, where immunolabeled cells were present throughout the rostro-caudal extent of the nucleus. c-Fos expression was concentrated in the parvocellular region and largely absent from magnocellular MVN. c-Fos-labeled cells were scattered throughout caudal SpVN, and the immunostained neurons in SVN were restricted to a discrete wedge-shaped area immediately lateral to the IVth ventricle. Immunofluorescence localization of c-Fos and glutamate revealed that approximately one third of the c-Fos-labeled vestibular neurons showed intense glutamate-like immunofluorescence, far in excess of the stain reflecting the metabolic pool of cytoplasmic glutamate. In the RVLM, which receives a direct projection from the vestibular nuclei and sends efferents to preganglionic sympathetic neurons in the spinal cord, we observed an approximately threefold increase in c-Fos labeling in the sGVS-activated rats. We conclude that localization of c-Fos protein following sGVS is a reliable marker for sGVS-activated neurons of the vestibulo-sympathetic pathway.

Practical Neurology Part 4: Dizziness on head movement

Benign positional vertigo (BPV) is the most common cause of episodic vertigo. It results from activation of semicircular canal receptors by the movement of calcium carbonate particles (otoconia) which dislodge from the otolith membranes. During changes in head position, the otoconia either float freely within the semicircular canal duct (canalithiasis) or adhere to and move with the cupula of the canal (cupulolithiasis). BPV from canalithiasis evokes brief spells of vertigo lasting seconds and can be diagnosed at the bedside by provoking paroxysmal vertigo and nystagmus on tilting the head in the plane of the affected canal. The nystagmus has a unique rotational axis perpendicular to the affected canal. The Dix-Hallpike test is a simple means of confirming the diagnosis in patients presenting with episodic vertigo or imbalance. Audiovestibular tests are only indicated if a symptomatic primary underlying inner ear disease is suspected. In over 80% of patients, BPV can be treated successfully with a single bedside Epley (particle-repositioning) manoeuvre, which can be performed by any medical practitioner.