Dizziness and Head Injury

Dizziness, whether vague or specifically rotational, is a common sequel to head injury, and is often postural. One hundred and sixty-five patients with this symptom were examined. The simple posture tests employed to detect positional nystagmus are described. This physical finding was present in one-quarter of the entire group, and in nearly one-half of cases of longitudinal fracture of temporal bone. In such cases, it is an objective finding that corresponds precisely to the patient''s complaint of vertigo.Transverse fracture of temporal bone destroys the inner ear in both cochlear and vestibular parts. Longitudinal fracture is commoner and causes bleeding from the ear; inner-ear damage is usually minor.In the rare cases where persisting postural vertigo and positional nystagmus are disabling, relief of the symptom may be achieved by vestibular denervation of the affected side.     

Quantitative analysis of benign paroxysmal positional vertigo fatigue under canalithiasis conditions

In our daily life, small flows in the semicircular canals (SCCs) of the inner ear displace a sensory structure called the cupula which mediates the transduction of head angular velocities to afferent signals. We consider a dysfunction of the SCCs known as canalithiasis. Under this condition, small debris particles disturb the flow in the SCCs and can cause benign paroxysmal positional vertigo (BPPV), arguably the most common form of vertigo in humans. The diagnosis of BPPV is mainly based on the analysis of typical eye movements (positional nystagmus) following provocative head maneuvers that are known to lead to vertigo in BPPV patients. These eye movements are triggered by the vestibulo-ocular reflex, and their velocity provides an indirect measurement of the cupula displacement. An attenuation of the vertigo and the nystagmus is often observed when the provocative maneuver is repeated. This attenuation is known as BPPV fatigue. It was not quantitatively described so far, and the mechanisms causing it remain unknown. We quantify fatigue by eye velocity measurements and propose a fluid dynamic interpretation of our results based on a computational model for the fluid–particle dynamics of a SCC with canalithiasis. Our model suggests that the particles may not go back to their initial position after a first head maneuver such that a second head maneuver leads to different particle trajectories causing smaller cupula displacements.     

Performance of DHI Score as a Predictor of Benign Paroxysmal Positional Vertigo in Geriatric Patients with Dizziness/Vertigo: A Cross-Sectional Study

Background

Dizziness/vertigo is one of the most common complaint and handicapping condition among patients aged 65 years and older (Geriatric patients). This study was conducted to assess the impact of dizziness/vertigo on the quality of life in the geriatric patients attending a geriatric outpatient clinic.

Settings and Design

A cross-sectional study was performed in a geriatric outpatient clinic of a rural teaching tertiary care hospital in central India.

Materials and Methods

In all consecutive geriatric patients with dizziness/vertigo attending geriatric outpatient clinic, DHI questionnaire was applied to assess the impact of dizziness/vertigo and dizziness associated handicap in the three areas of a patients’ life: physical, functional and emotional domain. Later, each patient was evaluated and underwent Dix-Hallpike maneuver by the physician who was blind of the DHI scoring of the patient.

Statistical Analysis Used

We compared means and proportions of variables across two categories of benign paroxysmal positional vertigo (BPPV) and non-BPPV. For these comparisons we used Student’s t-test to test for continuous variables, chi-square test for categorical variables and Fisher’s exact test in the case of small cell sizes (expected value<5).

Results

The magnitude of dizziness/vertigo was 3%. Of the 88 dizziness/vertigo patients, 19 (22%) and 69(78%) cases, respectively, were attributed to BPPV and non-BPPV group. The association of DHI score ≥50 with the BPPV was found to be statistically significant with x² value = 58.2 at P<0.01.

Conclusion

DHI Score is a useful tool for the prediction of benign paroxysmal positional vertigo. Correct diagnosis of BPPV is 16 times greater if the DHI Score is greater than or equal to 50. The physical, functional and emotional investigation of dizziness, through the DHI, has demonstrated to be a valuable and useful instrument in the clinical routine.     

Anti-Ri-associated paraneoplastic cerebellar degeneration. Report of a case and revision of the literature

Paraneoplastic cerebellar degeneration associated with anti-Ri antibodies mainly presents with opsoclonus-myoclonus-ataxia. We report here the case of a patient with anti-Ri-antibody paraneoplastic syndrome, who presented four years after treatment for small-cell lung cancer (SCLC) with oscillopsia and gait disorder. On neurological examination vertical nystagmus, ataxic gait and postural tremor of all four limbs was detected. He died one year after the onset of the symptoms because of a acute exacerbation of his severe chronic obstructive pulmonary disease. No SCLC relapse or new cancer has been detected during the one-year follow-up period.To our knowledge, our patient is the first case of anti-Ri associated disorder with oscillopsia and vertical nystagmus as the initially prominent clinical features. The findings of this case study support the variability of anti-Ri-antibody-associated paraneoplastic syndrome. Further studies must be directed to better characterize the mechanisms underlying this syndrome. Finally, paraneoplastic neurological syndromes should be kept in mind also when a neoplastic disease is not demonstrated.     

视频眼震检查在主诉非典型眩晕患者中的临床应用价值

目的:探讨视频眼震检查在主诉非典型眩晕患者中的临床应用价值。方法:分析118例主诉非典型眩晕患者的裸眼眼震、视频眼震,结合查体、已有的或者后续的双温试验、听力学检查以及影像学等临床资料,评估视频眼震检查的应用对前庭疾病临床诊断的意义。结果:主诉持续头昏沉感患者10例、飘飘感23例;低头、抬头、坐起、躺下、翻身等头部位置改变时不穏感50例;或者上述动作引起瞬间旋转感35例。以上患者均行自发性眼震检查和位置试验,裸眼下观察到眼震的患者有19例(19/118,16.1%),均得到临床诊断;视频下记录到眼震67例(67/118,56.8%),其中60例(60/118,50.8%)得出临床诊断。两种方法的眼震检出率比较差异有显著的统计学意义(P0.05),视频眼震检查的检出率显著高于裸眼下观察。结论:视频眼震检查所采用的眼罩有暗室诱发的效果,方便快捷,较裸眼观察,可显著地增加以下几种主诉非典型(转头时飘飘感,低头、抬头、坐起、躺下、翻身等头部位置改变时不穏感或者瞬间旋转感)眩晕患者眼震的临床诱发率,提供进一步的诊查方向,提高临床上对主诉非典型眩晕患者的诊断率。     

Cryptogenic Drop Attacks: An Affliction of Women

A drop attack was defined as falling without warning, not apparently due to any malfunction of the legs, not induced by change of posture or movement of the head, and not accompanied by vertigo or other cephalic sensation. All 33 patients attending a neurological clinic with a primary complaint fulfilling these criteria were women, and a further seven examples were found by questioning 200 consecutive patients at a gynaecological clinic. No affected male was found.In all but one patient, falls occurred only when walking. They were not due to wearing high-heeled shoes. The average age at onset was 44·5 years and in younger women onset was often during pregnancy. The accepted causes of drop attacks were not found with certainty in any of these patients. The sex incidence and the circumstances of the falls suggest that the cause may lie in differences between the two sexes in the mechanism of walking rather than in any central disturbance. Drop attacks in women commonly occur as an isolated symptom for many years, and although distressing have no serious prognostic implications.     

The optokinetic head nystagmogram of the frog.

An electronic device for recording optokinetic head nystagmus is described. By feeding a point-like mass (radiator) with an alternating current generator, alternating voltage can be measured on a large flat plate (receptor), which depends on the distance of the radiator from the receptor. The radiator was fixed on the head of the frog, and could move between a pair of receptors. Voltage changes during head motions can be recorded in the form of nystagmogram. The head nystagmogram of the frog proved to be similar to that of mammals. Rotation of the optokinetic drum to one direction for several minutes resulted in habituation (decrease of frequency or stopping of head motions). Based on the frequency and amplitude pattern several types of optokinetic head nystagmus could be identified.     

Optokinetic horizontal head nystagmus in the frog after regeneration of transected retinal fibres

The recovery of optokinetic responses during regeneration of transected retinal fibres was studied. Regenerated optic fibres were demonstrated by the cobaltfilling technique. After transection of the chiasma in the midline in most of the cases regenerating retinal fibres did not cross, but terminated in ipsilateral visual centres. Aberrant fibres were found in the telencephalon, the periventricular region of the diencephalon, anterior-, posterior- and ventral tegmental commissures and in the isthmic nucleus. In one group of animals optokinetic responses did not return after regeneration of retinal fibres. Re-innervation was either symmetrical on both sides from one eye, or terminal fibres were disorganized. In the second group of animals normal optokinetic nystagmus (OKN) returned. In these cases the fibres were symmetrically distributed on both sides or, alternatively, the crossed fibres outnumbered the ipsilateral ones. The third group of animals showed reversed OKN, spontaneous turning of the head, circling or head nystagmus. Here the majority of regenerated fibres termined ipsilaterally. When the OKN returned, the retinal projection was always restored in the pretectal region. Contrary to our earlier work, we concluded that the basal optic nucleus is not essential for horizontal optokinetic head nystagmus because in a few animals, retinal fibres did not invated this nucleus, and in spite of this the OKN could be evoked. We think now that the most important structure (as an input channel) for horizontal OKN of frogs is the pretectal region.     

Soybean lipoxygenase-1 oxygenates synthetic polyenoic fatty acids with an altered positional specificity: evidence for inverse substrate alignment

The positional specificity is the decisive enzyme property for classification of lipoxygenases and for the currently used lipoxygenase nomenclature. It has been reported before that soybean lipoxygenase-1, which oxygenates polyenoic fatty acids at alkaline pH to the corresponding n - 6 hydroperoxy derivative, exhibits a different positional specificity when either the reaction conditions or the substrate structure is altered. To investigate the impact of structural substrate modifications on the positional specificity of this enzyme and to force an inverse substrate binding, we synthesized arachidonic acid analogues modified at the omega-terminus. Care was taken that the double bond system remained unchanged so that hydrogen abstraction from all three bisallylic methylenes was theoretically possible. We found that omega-modification of arachidonic acid leads to an impaired substrate affinity and a reduced reaction rate, but we did not detect any 5-lipoxygenation products, suggesting that structural modification of the omega-end may not be sufficient to force an inverse substrate orientation. However, when both ends of the fatty acid chain (omega-terminus and free carboxylate) were modified simultaneously, a considerable share of 5-lipoxygenation products was detected. These results indicate that introduction of polar or bulky groups at the methyl terminus of polyenoic fatty acids was not sufficient to force an inverse substrate orientation. However, simultaneous introduction of an omega-OH group and methylation of the carboxylate led to formation of significant 5-lipoxygenation products, suggesting an inverse head to tail substrate orientation.     

Positional Information and Positional Signalling in Hydra

A model is proposed for regulation and regeneration of the headend of hydra in terms of positional information, which involvestwo gradients. One is a diffusible substance made at the headend, which may be regarded as a positional signal. The otheris a more stable cellular parameter which is the positionalvalue. The rule for head end formation is that the concentrationof the diffusible substance falls a threshold amount below thepositional value. This model, for which some computer simulationis provided, can account for head end formation in a wide varietyof grafts. Evidence for a diffusable signal is provided by experimentsin which the time/distance relationships for head inhibitionby a grafted head are determined. Changes in positional valueduring regulation have been assayed and are much slower awayfrom the boundary. Polarity is interpreted in terms of the interactionbetween the two gradients. The biochemical basis of the gradientsis not known, but an approach to the problem has been made bytreating hydra with a variety of chemical agents.     

Controlled trial of trimipramine,monoamine oxidase inhibitors,and combined treatment in depressed outpatients.

A study was carried out in which 135 mildly or moderately depressed outpatients were randomly allocated to one of five groups receiving six weeks'' treatment weith antidepressant drugs. The groups received a tricyclic antidepressant (trimipramine; mean dose 106 mg at night) or a monoamine oxidase inhibitor (MAOI) (phenelzine or isocarboxazid; mean doses 45 and 32 mg/day respectively), or a combination of the two (phenelzine plus trimipramine or isocarboxazid plus trimipramine). Various scales were used to measure depression before and at one, three, and six weeks of treatment, and results were assessed blindly. The tricyclic antidepressant was found to be consistently superior to the MAOIs and the combined treatments. Some differential indicators of response to the various antidepressants were found--for example, patients with initial complaints of dizziness, suicidal ideas, irritability, and insomnia and a longer duration of illness were more likely to respond to trimipramine--but these were of only modest significance. Side effects were not troublesome in any group. It is concluded that neither MAOIs nor MAOIs combined with tricyclic antidepressants are the treatment of first choice in unselected outpatients with mild or moderate depression.     

The roles of head movements in the search and capture strategy of a tern (Aves, Laridae)

 Gull-billed terns (Gelochelidon nilotica) were video-filmed while searching for and capturing fiddler crabs. Search consists of a vertical head nystagmus, with fast upward flicks and downward slow phases made at the angular speed of the substrate in the approximate direction of the bill. The bill points down at about 60° during hunting, but is brought up to 15° from time to time, which brings the visual streak into line with the horizon; 45° roll movements of the head are consistent with alternation between the use of the temporal and central foveas to view the same object. When a crab has been detected the nystagmus is suspended, and the tern tracks the crab continuously as it manoeuvres into a catching position. This may involve tucking the head under the body so that the bill is 45° behind the vertical, and flying up and backwards for some metres, straightening up the head at the same time. Accepted: 7 November 1998     

On the Vertigo Due to Static Magnetic Fields

Vertigo is sometimes experienced in and around MRI scanners. Mechanisms involving stimulation of the vestibular system by movement in magnetic fields or magnetic field spatial gradients have been proposed. However, it was recently shown that vestibular-dependent ocular nystagmus is evoked when stationary in homogenous static magnetic fields. The proposed mechanism involves Lorentz forces acting on endolymph to deflect semicircular canal (SCC) cupulae. To investigate whether vertigo arises from a similar mechanism we recorded qualitative and quantitative aspects of vertigo and 2D eye movements from supine healthy adults (n = 25) deprived of vision while pushed into the 7T static field of an MRI scanner. Exposures were variable and included up to 135s stationary at 7T. Nystagmus was mainly horizontal, persisted during long-exposures with partial decline, and reversed upon withdrawal. The dominant vertiginous perception with the head facing up was rotation in the horizontal plane (85% incidence) with a consistent direction across participants. With the head turned 90 degrees in yaw the perception did not transform into equivalent vertical plane rotation, indicating a context-dependency of the perception. During long exposures, illusory rotation lasted on average 50 s, including 42 s whilst stationary at 7T. Upon withdrawal, perception re-emerged and reversed, lasting on average 30 s. Onset fields for nystagmus and perception were significantly correlated (p<.05). Although perception did not persist as long as nystagmus, this is a known feature of continuous SSC stimulation. These observations, and others in the paper, are compatible with magnetic-field evoked-vertigo and nystagmus sharing a common mechanism. With this interpretation, response decay and reversal upon withdrawal from the field, are due to adaptation to continuous vestibular input. Although the study does not entirely exclude the possibility of mechanisms involving transient vestibular stimulation during movement in and out of the bore, we argue these are less likely.     

Static cervical-ocular reflex and optokinetic reflex interaction in rabbits

Summary The effect that tonic eye deviations, induced by angular deviation of the torso, have on the characteristics of optokinetic (OK) nystagmus was studied in rabbits. When the slow component of the OK nystagmus moved in the direction of the tonic eye deviation, the amplitude of the slow and fast components of the nystagmus was decreased and their frequency was increased, whereas when the slow component moved in the opposite direction, the amplitude and the frequency of the nystagmus were not different from those when the head and torso were aligned.Under the influence of neck reflexes, the total range of eye movements was double that when the torso was aligned with the head. The place in the orbit where the fast-component is initiated — the so-called fast-component threshold — was deviated in the direction of the neck-reflex-induced tonic eye deviation. The characteristics of the fast component, however, except for its amplitude, were not affected by the change of location of the fast-component threshold.These data indicate that the OK reflex function, as judged by measurement of the slow component velocity, is not affected by neck-vestibular reflexes. They also show that the fast-component threshold is dependent on parameters other than the actual orbital position and that there must be an internal representation of the range of possible eye movements within the brain to regulate the production of fast components.Abbreviations OK optokinetic - CW clockwise - CCW counterclockwise - CNS central nervous system This work was supported by grants NS07059, NS09823, and NS08335 from the National Institutes of Health     

Clinical Detection of Acute Vestibulocerebellar Disorders

The acute onset of vertigo, nystagmus and postural instability, without brain-stem signs, is commonly attributed to a disorder of the labyrinth, the vestibular, sensory end organ. Identical symptoms can occur, however, with discrete infarctions or hemorrhages involving the central vestibulocerebellum. Whereas acute labyrinthine disorders are usually benign and self-limited, vascular injuries of the cerebellum may produce swelling, compression of the brain stem and acute hydrocephalus one to four days after the onset of symptoms. Therefore it is important to accurately distinguish between labyrinthine and vestibulocerebellar disorders with the neurologic examination. Acute labyrinthine disease causes unidirectional nystagmus with past-pointing and falling in the opposite direction of the nystagmus, environmental vertigo in the same direction and suppression of the nystagmus with visual fixation. Disorders of the vestibulocerebellum do not produce this consistent pattern of findings.     

Gastroesophageal reflux: clinical presentations,diagnosis and management.

Symptomatic gastroesophageal reflux occurs daily in an estimated 7% of adults and weekly or monthly in 29%. Untreated it can lead to esophageal erosions, ulceration and stricture formation. The pathogenesis is often multifactorial: defects in the function of the lower esophageal sphincter, esophageal clearance mechanisms and gastric emptying combine to produce frequent lengthy periods during which the lower esophagus is bathed in regurgitated acid. In most patients reflux disease is easily recognized as recurrent heartburn, regurgitation or dysphagia, or a combination. When acute chest pain or respiratory illness is the primary presenting complaint the patient needs particularly careful investigation to determine whether the symptoms are due to a primary cardiac or respiratory condition, are secondary to gastroesophageal reflux alone or represent a combination of disorders. Endoscopy with biopsy and long-term pH monitoring are the most reliable ways of determining whether reflux disease is present. Additional investigations, such as exercise testing, cardiac catheterization or inhalation challenge, may be needed in patients with cardiac or respiratory symptoms. Treatment should follow a stepped-care approach and in most patients should begin with changes in lifestyle, including dietary manipulation, reducing alcohol and cigarette consumption, and raising the head of the bed, together with appropriate use of antacids or alginate-antacid combinations. H2-receptor antagonists and agents to improve both gastric emptying and the tone of the lower esophageal sphincter may be added in sequence. Most patients will respond well to this regimen. Surgery should be considered only for those with intractable symptoms or with complications (e.g., stricture formation, bleeding, development of dysplastic epithelium in those with Barrett''s esophagus, or secondary pulmonary disease that does not respond to medical management). It is successful in 85% of well-selected patients and has few complications.     

Habituation of horizontal eye nystagmus in pigeon during alternation of central and eccentric rotations

Intact pigeons were rotated in the horizontal plane in the dark in different positions relatively to the rotation axis. At central rotations, the pigeon's head was in the rotation axis whereas at eccentric rotations it was displaced from the axis. Series of central and eccentric rotations were alternated. Each series consisted of 2-5 rotations using angular velocity trapezoids. All stimuli producing habituation were used at most 14 times each. Eccentric rotations did not prevent a gradual decrease of peak velocities of the slow component of primary nystagmus on transition from one series of central rotations to another in 17 pigeons (group 1). The increase of peak velocities was observed in 2 pigeons (group 2). In group 1, a direct dependence among alterations of this parameter of primary nystagmus, modifications of its duration, and variations of peak velocities of secondary nystagmus, were observed. If two identical stimuli did not follow in sequence directly, the effect of the second one produced same nystagmus changes as were observed in present pigeon by comparison of the first and last responses in the series of the central rotations. If they follow one by one, in many cases the second stimulus in the pair produced an increase of peak velocity of primary and secondary nystagmus and rise of delay of the point of primary nustagmus peak velocity. These variations were not random (probability, > 95%).     

Compensatory processes during unilateral loss of vestibular function]

Changes in the compensation of the sequences of the unilateral loss of the labyrinthine function were studied in rabbits. Destruction of the labyrinth was accompanied by ocular nystagmus, increase of frequency of respiration and heart contractions, and EEG-activation. Investigations carried out showed these reactions to be extinguished at different time. At the late periods of labyrinthectomy a considerable asymmetry of nystagmus reaction to the angular accelerations equal in intensity, but opposite in direction was revealed. Stimulation of an intact otolith labyrinth was accompanied by the appearance of positional nystagmus. The results obtained indicated imperfection of the compensatory mechanisms during complete unilateral loss of the vestibular function.     

Atrial fibrillation in the elderly

Atrial fibrillation (AF) is prevalent in the elderly (affecting 5% of persons aged >or= 65 years and around 10% of those aged >or= 80 years old) and is associated with stroke, heart failure and poor quality of life. The symptoms of AF are palpitations, fatigue, reduced exercise capacity, dyspnea or dizziness. AF is associated with comorbidity, mainly hypertension in outpatients, and ischaemic heart disease and heart failure in hospitalized patients. Two therapeutic strategies are available to treat arrhythmia: rhythm control or frequency control. In many elderly patients with AF, frequency control is an effective option, particularly when there is heart failure, contraindications to antiarrhythmic agents or when cardioversion is not indicated. Anticoagulation is the main measure to reduce stroke risk. If anticoagulation is not appropriate for a patient, antiaggregants can be used, but the benefit is clearly lower than that provided by anticoagulation.