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Biomedical subjects

C R Pfaltz

Publications and source records attributed to C R Pfaltz.

At least 37 records · Page 2Linked to original sources
PubMed1988

Calcium-entry blockers in the treatment of vestibular disorders.

Based upon the results of a double-blind study carried out in a series of 120 patients suffering from vertigo and objective vestibular symptoms, we made the following observations during the treatment of vestibular disorders by means of calcium-entry blockers: Subjective symptoms regress fairly well during treatment, but no better than after betahistine-dihydrochloride (BHC) or thietylperazine therapy (TP). Objective assessment of the therapeutic action of calcium antagonists on vestibular dysfunction is based on the results of the Harmonic Acceleration test, which was carried out by using a computerized rotatory chair. The most reliable parameter with respect to the objective assessment of the experimentally induced vestibular responses (VOR) is the gain. Our test results show a progressive decrease in GAIN, indicating a depressive or inhibitory effect of the calcium antagonist flunarizine upon the VOR. If we compare these results with those obtained in the betahistidine- and thiethylperazine groups, we cannot confirm the same decline in GAIN within the latter two groups. A statistical analysis demonstrates a significant difference between the F-gain on the one hand, and the BHC gain and TP gain on the other hand.

Calcium Channel Blockers↗
PubMed1987

Postural coactivation and adaptation in the sway stabilizing responses of normals and patients with bilateral vestibular deficit.

The experiments were designed to test two hypotheses and their corollaries: 1. That adaptation of EMG responses to support surface rotations is due to a decrease in the gain of proprioceptively triggered long-loop stretch reflexes (Nashner 1976), and that the adaptation is dependent on a normally functioning vestibular system (Nashner et al. 1982); 2. That EMG responses to rotations are generated primarily by vestibulo-spinal reflexes triggered by head accelerations (Allum and Pfaltz 1985) and comprise a coactivation of opposing leg muscles (Allum and Büdingen 1979). Adaptation with successive dorsi-flexive rotations of the support surface was investigated in the EMG responses of the ankle muscles, soleus (SOL) and tibialis anterior (TA), as well as the neck muscles, trapezius (TRAP) and splenius capitis (SPLEN CAP), both for normal subjects and for patients with bilateral peripheral vestibular deficit. Both normals and patients who first received the stimulus with their eyes open demonstrated decreasing activation at medium latency (ML), that is, with an onset at about 125 ms, and long latency (LL) responses with an onset ca 200 ms. This was the case for both ankle and neck muscles when the EMG response areas for the first 3 and second 7 of 10 trials were compared. Ankle muscle responses in the patients were diminished in area with respect to normals both with the eyes open and with the eyes closed. Ankle torque recordings from the patients were also smaller in amplitude, and these attenuated differently from normal torque responses. Functional coupling of the opposing ML and LL SOL and TA muscle responses was confirmed by the nearly coincident onset times and significantly correlated EMG response areas. At ML, ankle torque was highly correlated with TA activity when the influence of SOL was controlled. At LL, SOL activity was highly correlated with torque when the influence of TA was controlled. The delay of torque adaptation beyond the period of ML activity in normals, but not in the patients was attributed to the proportionally balanced coactivated muscle patterns producing a consistent force output and level of stability in normals. The results indicate that the adaptation in EMG response amplitudes during a sway stabilisation task is not dependent on a normally functioning vestibular system nor on visual inputs but rather appears to be due to a generalized habituation in the postural control system.(ABSTRACT TRUNCATED AT 400 WORDS)

Adolescent↗
PubMed1987

[Binding of serum immunoglobulins to human inner ear tissue in inner ear hearing loss: methodologic limits].

The immunopathological processes possibly involved in cryptogenic sensorineural hearing loss were investigated. In a pilot study the sera from 66 patients were tested by the indirect immunofluorescence technique for immunoglobulins which bind to normal human inner ear tissue. The reaction was positive in two thirds of all patients with sudden hearing loss, especially bilateral. This was mostly for IgG, and to the organ of Corti. Others have found that Corti's organ showed marked degenerative changes in cases of sudden hearing loss, examined by histology. The reaction was positive in half of the patients with progressive sensorineural hearing loss. It was noticeable that positive reactions for IgA were twice as frequent in sera of patients with progressive hearing loss than in those with sudden deafness. In a control study, the sera of ten patients were tested in parallel by the same method on histological sections of inner ears taken from four individuals. Similar results were found for the sera of two patients only. The sera of the remaining eight patients revealed very inconsistent reaction patterns. These preliminary results may indicate that temporary or permanent humoral (auto) immune mechanisms could have occurred in certain inner ear diseases. So far however reliable diagnostic methods have not been established, and not enough patients have been followed up.

Adolescent↗
PubMed1987

[Vestibulospinal reflexes in differentiating between organic and functional (psychogenic) causes of vertigo].

Recent investigations comparing the postural responses of normals and patients with bilateral peripheral vestibular deficit to a sudden backwards tilt of the support surface about the ankle joints have permitted an objective definition of the timing and amplitude of vestibulo-spinal reflex (VSR) EMG responses in ankle and neck muscles. The muscle contractions result in a sway stabilizing action correcting for induced body tilt, whose effect may be observed in ankle torque, and body and head angular acceleration records. The same techniques were used to monitor VSR responses of 10 patients with suspected simulated, aggravated, or psychogenic vertigo--vertigo of functional origin. Two cases, presented in detail, illustrate the identification of weak reflex responses for patients aggravating an organic VSR pathology during the Romberg test and the identification voluntarily controlled destabilizing responses for patients with a simulated or psychogenic vertigo. Recording the vertical vestibulo-ocular reflex in the same rotation plane as induced tilt is shown to provide valuable additional information on a possible peripheral vestibular pathology. It is concluded that VSR responses time-locked to a vestibular stimulus provide an improved means of identifying a functionally based vertigo.

Diagnosis, Differential↗
PubMed1985

Visual and vestibular contributions to pitch sway stabilization in the ankle muscles of normals and patients with bilateral peripheral vestibular deficits.

Vestibular, visual, and proprioceptive influences on muscle activity correcting for backwards body tilt were investigated in normals and patients with bilateral peripheral vestibular deficits. Body tilt was induced by a dorsi-flexion rotation of the feet about the ankle joints while the subject stood on a force measuring platform. Ankle muscle activity and torque were monitored as upright stance was reestablished, and correlated with head angular accelerations and neck muscle activity. In normals with eyes closed, soleus stretch reflex activity at 50-80 ms was followed by two bursts of tibialis anterior (TA) EMG activity at ca 80 and 125 ms from the onset of 36 deg/s, 3 deg amplitude platform rotations. Neck muscle activity rotated the head backwards at the same time as TA activity rotated the body forwards about the ankle joints. Under the influence of vision, i.e. eyes open, slight increases in the second burst of TA activity, and ankle torque were observed. When the subjects sat, and were instructed to activate TA rapidly on onset of the platform movement, TA EMG activity increased gradually at ca. 150 ms and not as a burst. In patients with long-lasting bilateral vestibular deficits, both bursts of TA activity were significantly less than normal with eyes closed. Consequently sway correcting torques were abnormally low and all but one of the patients fell over backwards. With eyes open, TA activity was slightly less than, and ankle torques were approximately equal to normal values. In contrast to normals, TA responses obtained in standing and sitting positions were not significantly different. Neck EMG activity varied from normal, consisting of a long burst 100 ms in duration. The present data indicate that a coordinated pattern of ankle, and neck muscle activity occurs during the first 150 ms following induced backward tilt. Ankle muscle activity corrects for the body sway, and neck muscle activity attempts to stabilise the head with respect to earth fixed coordinates. It is proposed that the vestibulo-spinal reflex system predominantly underlies the genesis and coordination of this muscle activity.

Adult↗
PubMed1985

Computed tomographic findings in Ménière's disease.

Symptoms in Ménière's disease are explained by hydrops of the endolymphatic system with recurrent ruptures of the membranous labyrinth. The primary cause of the increased endolymphatic volume appears to be an imbalance between secretion and resorption of endolymph which may be due to an obstruction of the endolymphatic duct and sac, located in the vestibular aqueduct (VA). Non-visualization or narrowing of the latter have been demonstrated by conventional tomography. Also, sclerosis and hypoplasia of the retrolabyrinthine portions of the temporal bone have been documented. By high resolution computed tomography (CT) we prospectively tried to demonstrate morphological alterations in 10 patients with Ménière's disease. These were compared with a group of 14 non-Ménière patients. Visualization of the VA as well as perilabyrinthine pneumatization were assessed and the width of the retrolabyrinthine part of the temporal bone was measured. Whereas there was a slight difference in the average retrolabyrinthine width (3.8 mm in Ménière versus 5.8 in non-Ménière cases) and degree of pneumatization, there was a distinctly decreased visualization of the VA in the Ménière group. As findings were always bilateral and only 3 of 20 temporal bones showed peripheral hypopneumatization, possibly due to chronic otitis media, the theory of a predisposing constitutional abnormality must be taken into consideration. However, we were not able to confirm a statistically proven usefulness of the CT technique in identifying an anatomical abnormality which is directly in correlation with the side of the lesion in cases of unilateral Ménière's disease.

Adult↗
PubMed1985

[Immunopathology of the inner ear].

Immunologically mediated tissue lesions or functional disturbances can result from immune responses either to foreign antigens or autoantigenic constituents. Before a disease or a functional disorder can be called an (auto)immune disease, it must be established that immunological processes are involved in its etiology and/or pathogenesis. After reviewing the available data on immunology and on research on immunobiology of the inner ear, as well as clinical observations on disorders of the inner ear of possibly immunological origin, an attempt is made to determine whether (auto)immunopathology can be assumed in some patients with sensineural hearing loss. In patients with disorders presently recognized as autoimmune diseases, no hearing loss has been described so far. However, serum antibodies can be found via the indirect immunofluorescence method in some patients having functional disorders of the inner ear. These serum antibodies interact with normal human inner ear tissue. However, as long as immunopathological mechanisms have not been confirmed, these disorders should merely be called "diseases with autoimmune markers." It has been shown in animal experiments that the production of autoantibodies against inner ear components is associated with morphological and functional changes of the inner ear. The human endolymphatic sac releases secretory IgA into the lumen. Its epithelium contains (intraepithelial) lymphocytes, whereas lymphocytes, plasma cells (IgA, IgG) and macrophages occur in the perisaccular region. In this manner, the inner ear has its own immune system, which can possibly react independently of the systemic immune system.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1984

Operative treatment for otosclerosis. Comparative study of long-term results following substitution of stapes by free cartilage grafts.

This comparative study of long-term results following the substitution of stapes by free cartilage grafts is based on 500 stapedectomies. The patients were operated on by the same surgeon (first author) and followed-up for a period of 5-20 years. Postoperative results, compared with the results of other stapedectomy techniques, demonstrate a statistically significant difference in favour of the cartilage implant technique with respect to the overall functional success rate and the incidence of postoperative complications.

Adolescent↗