Biomedical subjects

S Tanyeri

Publications and source records attributed to S Tanyeri.

7 recordsLinked to original sources

PubMed1993

Magnetic stimulation in hemifacial spasm and post-facial palsy synkinesis.

The facial nerve was stimulated trascranially with a magnetic stimulator in 14 normal controls, 14 hemifacial spasm patients, and 16 post-facial-palsy synkinesis patients. Magnetic stimulation in normal controls revealed muscle responses which had latencies with a mean value of 4.99 +/- 0.49 ms and amplitudes of 2.41 +/- 1.08 mV. In the same group, transosseal conduction time was calculated to be 1.20 +/- 0.13 ms. In the hemifacial spasm group, the amplitudes of the responses on the affected sides were lower as compared to the unaffected sides (mean values 1.78 vs. 2.41 mV, P = 0.01). Also, the threshold to magnetic stimulation was elevated on the affected sides. These findings are suggestive of the presence of a hypoexcitability to magnetic stimulation in the root entry zone. In the post-facial-palsy synkinesis patients, magnetic stimulation of the affected sides resulted in responses with long latencies and low amplitudes (mean latency 6.34 ms, mean amplitude 0.90 mV). In the recordings made with magnetic stimulation, the difference of the latencies between the two sides was larger as compared to those obtained by electrical stimulation. The transosseal conduction time was also remarkably prolonged on the affected side. These findings may suggest that magnetic stimulation can be an effective method of showing intracranially located lesions of the facial nerve.

Adult↗

PubMed1993

Influence of sensory manipulation on postural control in Parkinson's disease.

Postural control was assessed on a tilting platform system in 20 patients with idiopathic Parkinson's disease and 20 age-matched controls. The amount of information provided by vision and lower limb proprioception was varied during the experiment to investigate the influence of changes in sensory cues on postural control. The patient group with clinical evidence of impaired postural control (Hoehn and Yahr III) had significantly higher sway scores over all sensory conditions than either the Hoehn and Yahr II group or controls. The pattern of sway scores indicated that no obvious deficit in the quality, or processing, of sensory information was responsible for the postural instability observed in this group. The patients in both Hoehn and Yahr groups were also able to respond appropriately to potentially destabilising sensory conflict situations and significantly improved their sway scores when provided with visual feedback of body sway. The results indicate that in Parkinson's disease, the main site of dysfunction in postural control is likely to be at a central motor level.

Adult↗

PubMed1992

Saccadic eye movements in Parkinson's disease: I. Delayed saccades.

The saccadic eye movements of nine patients with Parkinson's disease were compared to those of nine age-matched controls in two paradigms generating volitional saccades. In both paradigms, subjects had to make delayed saccades to peripheral LED targets: a peripheral target appeared 700 msec before a buzzer sounded, the buzzer being the signal to make a saccade to the target. In the first paradigm ("centre-off"), the fixation target was extinguished simultaneously with buzzer onset. In the second ("centre-remain") it was not extinguished until 1000 msec later. The results showed that for outward saccades in both paradigms, there was no difference between Parkinsonian patients and controls, but saccadic latencies were significantly shorter in the "centre-remain" paradigm. The initial outward saccades were indistinguishable from the normal, reflex saccades of the same subjects. However, saccades returning to the centre (a type of remembered target saccade) were hypometric and showed multistepping. Both effects were more pronounced in patients with Parkinson's disease. The significance of these findings in terms of current hypotheses about the nature of the Parkinsonian saccadic deficit is discussed.

Aged↗

PubMed1991

The biological effects of implanted magnetic fields on the bone tissue of dogs.

Five titanium caps were implanted in the mandibles of five dogs. Three caps contained Sm-Co mini magnets and two caps were empty. The aim of this study was to determine if implanted magnetic fields had any biological effects on the bone tissue of dogs. At the end of 6 months, the animals were sacrificed and segments containing implants and segments from the side opposite the implants, for control, were removed. Sections were made from the specimens and no pathology was seen upon microscopic examination.

Alveolar Process↗

PubMed1990

Saccadic eye movements in essential blepharospasm.

To provide evidence of an organic pathology for essential (idiopathic) blepharospasm, reflex saccadic eye movements in response to randomly stepped visual targets were assessed in seven affected patients and seven age-matched controls using the magnetic scleral search coil technique. The results indicate a significant prolongation in latency and a reduction in gain of horizontal saccades, and an increase in latency and reduction of peak velocity of large downward saccades. These findings suggest an organic component to the aetiology of blepharospasm, the pathology of which also appears to involve the oculomotor system. The pattern of the oculomotor disorder does not allow specific localisation but is consistent with the underlying pathology being localised in the basal ganglia.

Adult↗

PubMed1990

Antisaccades and remembered saccades in Parkinson's disease.

Antisaccades were studied in ten patients with mild to moderate Parkinson's disease and ten age-matched normal controls. Remembered saccades and reflex saccades were assessed for comparison. In the population of patients who showed the previously reported abnormalities of remembered saccades, antisaccades were indistinguishable from those of controls in latency, gain and peak velocity. This finding implies that antisaccades are mediated through pathways which are unaffected by Parkinson's disease, and which are therefore presumably distinct from pathways mediating other voluntary saccades.

Aged↗

PubMed1989

Unilateral reversal of smooth pursuit and optokinetic nystagmus.

A patient is presented who has had three six-month episodes of oscillopsia over the last eight years. During the episodes, abnormal smooth pursuit and optokinetic nystagmus were noted, but there were no other abnormalities. Oculography during the most recent episode demonstrated that when tracking from right to left, the patient's smooth pursuit was reversed. There are several features of the case which suggest that the aetiology may be a form of congenital nystagmus. A possible alternative mechanism whereby such an abnormality might arise as an acquired lesion is discussed.

Adult↗