Search PubMed⌕ Search

Biomedical subjects

T Lempert

Publications and source records attributed to T Lempert.

At least 37 records · Page 2Linked to original sources
PubMed2001

Continuous vertigo and spontaneous nystagmus due to canalolithiasis of the horizontal canal.

The authors present a patient with benign paroxysmal positional vertigo of the right horizontal semicircular canal who developed persistent vertigo with spontaneous horizontal nystagmus to the left and caloric hypoexcitability on the right after a head shaking maneuver. Both spontaneous nystagmus and canal paresis resolved after repeated shaking of the head. The most probable mechanism of this type of vertigo is plugging of the horizontal canal by otoconial particles with a negative endolymph pressure between plug and cupula.

Adult↗
PubMed2001

The interrelations of migraine, vertigo, and migrainous vertigo.

OBJECTIVE: To assess the prevalence of migrainous vertigo in patients with migraine and in patients with vertigo according to explicit diagnostic criteria that are presented for discussion. METHODS: The authors prospectively evaluated 200 consecutive patients from a dizziness clinic and 200 patients from a migraine clinic for migrainous vertigo based on the following criteria: 1) recurrent vestibular symptoms (rotatory/positional vertigo, other illusory self or object motion, head motion intolerance); 2) migraine according to the criteria of the International Headache Society (IHS); 3) at least one of the following migrainous symptoms during at least two vertiginous attacks: migrainous headache, photophobia, phonophobia, visual or other auras; and 4) other causes ruled out by appropriate investigations. In addition, the authors compared the prevalence of migraine according to the IHS criteria in the dizziness clinic group with a sex- and age-matched control group of 200 orthopedic patients. RESULTS: The prevalence of migraine according to the IHS criteria was higher in the dizziness clinic group (38%) compared with the age- and sex-matched control group (24%, p < 0.01). The prevalence of migrainous vertigo was 7% in the dizziness clinic group, and 9% in the migraine clinic group. In 15 of 33 patients with migrainous vertigo, vertigo was regularly associated with migrainous headache. In 16 patients, vertigo occurred both with and without headache, and in two patients headache and vertigo never occurred together. The duration of attacks varied from minutes to days. CONCLUSION: These results substantiate the epidemiologic association between migraine and vertigo and indicate that migrainous vertigo affects a significant proportion of patients both in dizziness and headache clinics.

Adult↗
PubMed2001

Benign paroxysmal positional vertigo.

Benign paroxysmal positional vertigo has been recognized as the most common vestibular disorder. The evolution of its pathophysiological concepts has led to current therapeutic strategies that have made it the most successfully treatable cause of vertigo.

History, 20th Century↗
PubMed1999

A modified Epley's procedure for self-treatment of benign paroxysmal positional vertigo.

We compared the efficacy of a modified Epley's procedure (MEP) and Brandt-Daroff exercises (BDE) for self-treatment of benign paroxysmal positional vertigo of the posterior semicircular canal (PC-BPPV) in 54 patients. PC-BPPV resolved within 1 week in 18 of 28 patients (64%) using the MEP and in 6 of 26 patients (23%) performing BDE (p<0.01). Type and adequate performance of the maneuver predicted treatment outcome in the multivariate analysis. The frequency of side effects was not significantly different between the two groups. The MEP is more suitable for self-treatment of PC-BPPV than conventional BDE.

Humans↗
PubMed1999

Horizontal linear vestibulo-ocular reflex testing in patients with peripheral vestibular disorders.

UNLABELLED: Horizontal eye movements in response to lateral head translation [linear vestibulo-ocular reflex (LVOR)] in normal subjects and in patients with bilateral vestibular failure (n = 14), unilateral vestibular nerve section (n = 9), and benign positional vertigo (n = 14), were studied. LVORs were elicited in darkness by step acceleration (0.24 g) of the whole body along the interaural axis. RESULTS AND CONCLUSIONS: (1) In patients with bilateral vestibular failure, LVORs were either absent or abnormal with asymmetries, diminished velocities, and prolonged latencies. Measurements of dynamic visual acuity during linear self-motion showed decreased performance in patients at 1.0 and 1.5 Hz, which correlated with absent or delayed LVORs. These findings demonstrate the functional role of LVORs for dynamic visual acuity. (2) Early after vestibular nerve section, LVORs were diminished or absent with head acceleration toward the operated ear and normal in the opposite direction. After 6-10 weeks, responses were symmetrical again. Thus, a single utricle appears to be polarized with respect to the LVOR early after unilateral vestibular loss generating mostly contraversive responses. (3) Patients with benign positional vertigo showed mostly normal LVORs, which can be explained by minor utricular damage or central compensation of a chronic unilateral deficit.

Acceleration↗
PubMed1998

Horizontal otolith-ocular responses in humans after unilateral vestibular deafferentation.

We studied horizontal eye movements evoked by lateral whole body translation in nine patients who underwent vestibular nerve section. Preoperatively, all had preserved caloric function on both sides. Testing was performed before, 1 week and 6-10 weeks after surgery. Patients were seated upright in an electrically powered car running on a linear track. The car executed acceleration steps of 0.24 g, randomly to the left and right in the dark. The normal response consisted of a bidirectionally symmetrical nystagmus with compensatory slow phases. Response asymmetry of the slow-phase velocity of the desaccaded and averaged eye position signal was less than 13% in normals (n = 21). Before surgery, patients' responses were mostly symmetrical. Postoperatively, responses were diminished or absent with head acceleration towards the operated ear in all patients, causing a marked asymmetry which averaged 56% after correction for spontaneous nystagmus. On follow-up, responses regained symmetry. Thus, early after vestibular nerve section, a single utricle produces a normal LVOR only with ipsilateral head translation. Therefore, afferents for the LVOR seem to originate from the mid-lateral area of the macula, where hair cells are stimulated in their on-direction during ipsilateral head translation. Compensation may depend on recovery of the off-directional responses from lateral hair cells of the remaining utricle.

Acceleration↗
PubMed1998

Vertigo.

Insight into the pathomechanisms of the benign positional vertigo syndromes has led to quick and effective treatment with positional manoeuvres. Our understanding of other causes of vertigo is progressing at a slower pace, but several recent findings regarding vestibular neuritis, vascular compression of the eighth nerve and psychogenic vertigo are of immediate clinical relevance.

Animals↗
PubMed1997

Selective vestibular damage in neurosarcoidosis.

We report a patient with neurosarcoidosis who developed bilateral benign paroxysmal positional vertigo (BPPV) of the posterior canals, deafness, and absent responses to conventional caloric and rotational vestibular testing. Additional rotation in the planes of the vertical semicircular canals revealed relative sparing of vertical canal function. This vertical-horizontal canal dissociation explains the presence of BPPV and suggests that the vestibular damage in this patient is secondary to a vasculitic neuropathy.

Adult↗
PubMed1997

[Syncope. Phenomenology and differentiation from epileptic seizures].

Confusion between syncope and epileptic seizures is a common problem in clinical practice. Recently, new insights into the phenomenology of transient cerebral hypoxia have been gained from video analysis of experimentally induced syncope. Common elements of syncope include multifocal and generalized myoclonus, tonic body extension, automatisms, vocalizations, eye deviations and hallucinations. Thus, it is not the presence or absence of these features but their specific character that distinguishes syncope from epileptic seizures. Other clues for differential diagnosis include precipitating factors, premonitory symptoms and postictal events, such as tongue bites and postictal confusion, which has been identified as the single most powerful factor discriminating syncope from epileptic seizures. In contrast, incontinence and head injury are common in both conditions. Investigations such as electroencephalogram, tilt testing and postictal prolactin or creatine kinase levels may aid diagnosis but are never diagnostic in isolation. In rare cases, hypoxic and epileptic mechanisms may interact within one attack.

Adult↗
PubMed1997

Effect of otolith dysfunction. Impairment of visual acuity during linear head motion in labyrinthine defective subjects.

Visual symptoms emerging after the loss of vestibular function are usually attributed to the dysfunction of semicircular canal vestibulo-ocular reflexes, as they have been shown to stabilize vision during angular head movements. However, natural head displacements involve both angular and linear motion, and therefore visual instability may occur because of defective otolith-ocular reflexes (OORs) which are the eye movements evoked by linear head acceleration. In this paper, the relationship between OORs and visual acuity during linear head motion was studied in normal subjects and 14 patients with bilateral loss of caloric responses. OORs were elicited in darkness by step acceleration (0.24 g) of the whole body along the interaural axis. Latency, slow phase velocity and asymmetry of the OOR were measured from the desaccaded and averaged electrooculographic trace. Visual acuity was assessed during sinusoidal lateral oscillation of the subject viewing an earth-fixed target, and vice versa with the subject stationary and the target moving at 0.5, 1.0 and 1.5 Hz. The task was to recognize numbers flashing up on a three digit light-emitting diode visual display. Normal subjects had symmetrical OORs with short latencies (< 130 ms). In patients, OORs were either absent (n = 2) or abnormal with asymmetries (n = 8), diminished velocities (n = 4) or prolonged latencies (n = 6). At high frequency oscillation (1.5 Hz), normal subjects invariably recognized more numbers during self-motion compared with target motion, whereas most patients did not. In patients, abnormal dynamic visual acuity was correlated with absent or delayed OOR responses. This is the first demonstration of a functional role of the OORs in that they contribute to visual stabilization during high frequency linear head motion. Bilateral vestibular failure commonly affects the OORs and thereby compromises dynamic visual acuity.

Acceleration↗
PubMed1997

Three hundred sixty-degree rotation of the posterior semicircular canal for treatment of benign positional vertigo: a placebo-controlled trial.

The canalithiasis hypothesis proposes that benign positional vertigo (BPV) is caused by dislodged otoconia that settle in the posterior semicircular canal (PSC). When head position is changed these particles move within the canal and induce abnormal endolymph flow. To clear the PSC from debris we developed a procedure that consists of a full circle of backward head rotation in the exact plane of the canal. Patients were seated in a three-dimensional motion device that rotated in steps of 110 degrees every 30 seconds. The first part of the study was conducted as an open trial; the second part followed a single-blinded, placebo-controlled design: Forward rotation (placebo) was applied first and backward rotation was applied 1 week later if BPV persisted. All patients were assessed with a symptom diary and, in the controlled trial, also with the Dix-Hallpike maneuver. In the open study 10 of 15 patients became asymptomatic after one treatment session. In the controlled trial all 15 patients remained symptomatic after forward rotation while 10 of 14 undergoing backward rotation were relieved from positional vertigo immediately (p = 0.004). The presence of secondary nystagmus during the procedure indicated a favorable outcome. Our findings provide evidence for the efficacy of canal-clearing procedures that validate the canalithiasis hypothesis of BPV.

Calculi↗
PubMed1997

Horizontal otolith-ocular responses to lateral translation in benign paroxysmal positional vertigo.

Benign paroxysmal positional vertigo (BPPV) is assumed to result from utricular damage, but it is controversial if patients have manifest utricular dysfunction. Therefore, we investigated linear vestibulo-ocular reflexes (LVORs) during lateral whole-body translation in 14 patients with unilateral BPPV. Patients were subjected to linear acceleration steps of 0.24 g along the interaural axis, which were applied randomly to the left and right, both in the dark and in the light with a visual target at a distance of 60 cm. The LVOR was measured by EOG from the slow phase velocity of the averaged and desaccaded compensatory eye movement. In normal cases, maximum asymmetry of LVOR velocity was 13% in the dark and 10% in the light. In patients, LVOR velocities were normal in the dark but mildly reduced in the light (p < 0.05). Five patients had mild LVOR asymmetries in the dark (range 18-38%) and two in the light (11 and 13%), but there was no consistent relationship to the affected side. The absence of gross changes of the LVOR may be explained either by minor utricular damage that is functionally irrelevant or by central compensation of a chronic unilateral deficit.

Adult↗