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Results for “REFLEX, ABNORMAL”

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At least 55 records · Page 3Linked to original sources
PubMed1997

Startle reflex abnormalities in women with sexual assault-related posttraumatic stress disorder.

OBJECTIVE: This investigation was designed to assess the acoustic startle response in treatment-seeking women with sexual assault-related posttraumatic stress disorder (PTSD). METHOD: Thirteen patients with sexual assault-related PTSD and 16 healthy female comparison subjects were recruited for participation in the study. Each patient met the full criteria for PTSD according to the Structured Clinical Interview for DSM-III-R. All subjects in the study were right-handed. The acoustic stimuli were bursts of white noise (92 dB and 102 dB) with a nearly instantaneous onset delivered binaurally through headphones. RESULTS: The magnitude of the startle response (eye blink) to the first stimulus was asymmetrically distributed in the PTSD patients but not in the comparison subjects: it was greater for the left eye than the right eye in the PTSD patients only. There was a differential asymmetry of startle response in the two subgroups of patients (recent PTSD and long-standing PTSD): the startle reflex was larger for the left eye than the right in the subgroup with recent PTSD but not in the group with long-standing PTSD. CONCLUSIONS: This study provides the first objective evidence of startle abnormalities in women with PTSD. The significantly greater startle responses for the left eye compared with the right in the PTSD subjects suggest a laterality effect. As suggested by the preclinical model of shock sensitization, it is possible that in a subgroup of individuals with PTSD, trauma may sensitize the startle reflex. This model may hold true in humans and is supported by the findings of greater startle response in the patients with recent-onset PTSD.

Acoustic Stimulation↗
PubMed1987

Testing the vestibular-ocular reflexes: abnormalities of the otolith contribution in patients with neuro-otological disease.

Conventional vestibular rotation testing with the head centered on the axis stimulates the semicircular canals evoking compensatory eye movements. If the head is placed forwards of the axis in an eccentric position the otoliths are also stimulated by a tangential linear acceleration acting laterally to the skull. In normal subjects the additional otolithic stimulus evokes compensatory eye movements with a higher gain than with head centred, particularly for high frequency (greater than 0.1 Hz) stimuli. The responses with head centred and eccentric in various patients with known/suspected neuro-otological abnormalities have been compared. Patients with vestibular neurinectomies who have asymmetrical head centred responses showed greater asymmetry with head eccentric at higher stimulus frequencies. Some patients with cerebellar lesions showed abnormally enhanced or depressed and asymmetrical responses with head eccentric in comparison with head centred responses, which could be normal. The enhancing effects could be specific to low frequency stimuli. All patients who showed abnormal responses with head eccentric also had positional nystagmus provoked by the gravity acceleration vector when the head was tilted laterally. The direction of the positional nystagmus with respect to the gravity vector was not necessarily the same as the direction of the effect on eye movements of lateral acceleration during eccentric oscillation. Patients with benign paroxysmal vertigo or chronic linear vertigo in whom otolithic abnormalities are suspected were not found to have abnormal responses with head eccentric. We conclude that this method of testing may be useful in elucidating pathophysiology but is not a decisive clinical test for the presence of disordered otolith function.

Acceleration↗
PubMed2000

Adrenergic and reflex abnormalities in obesity-related hypertension.

Previous studies have shown that essential hypertension and obesity are both characterized by sympathetic activation coupled with a baroreflex impairment. The present study was aimed at determining the effects of the concomitant presence of the 2 above-mentioned conditions on sympathetic activity as well as on baroreflex cardiovascular control. In 14 normotensive lean subjects (aged 33. 5+/-2.2 years, body mass index 22.8+/-0.7 kg/m(2) [mean+/-SEM]), 16 normotensive obese subjects (body mass index 37.2+/-1.3 kg/m(2)), 13 lean hypertensive subjects (body mass index 24.0+/-0.8 kg/m(2)), and 16 obese hypertensive subjects (body mass index 37.5+/-1.3 kg/m(2)), all age-matched, we measured beat-to-beat arterial blood pressure (by Finapres device), heart rate (HR, by ECG), and postganglionic muscle sympathetic nerve activity (MSNA, by microneurography) at rest and during baroreceptor stimulation and deactivation induced by stepwise intravenous infusions of phenylephrine and nitroprusside, respectively. Blood pressure values were higher in lean hypertensive and obese hypertensive subjects than in normotensive lean and obese subjects. MSNA was significantly (P:<0.01) greater in obese normotensive subjects (49.1+/-3.0 bursts per 100 heart beats) and in lean hypertensive subjects (44.5+/-3.3 bursts per 100 heart beats) than in lean normotensive control subjects (32.2+/-2.5 bursts per 100 heart beats); a further increase was detectable in individuals with the concomitant presence of obesity and hypertension (62.1+/-3. 4 bursts per 100 heart beats). Furthermore, whereas in lean hypertensive subjects, only baroreflex control of HR was impaired, in obese normotensive subjects, both HR and MSNA baroreflex changes were attenuated, with a further attenuation being observed in obese hypertensive patients. Thus, the association between obesity and hypertension triggers a sympathetic activation and an impairment in baroreflex cardiovascular control that are greater in magnitude than those found in either of the above-mentioned abnormal conditions alone.

Adrenergic Fibers↗
PubMed1986

Abnormal middle ear muscle reflexes and audiosensitivity.

Reversed or hyperactive stapedial reflexes are found in a wide variety of patients complaining of audiosensitivity, defined as a need to turn down the volume on audio equipment. This was checked in an independent sample of children with learning problems. One or both of these reflex abnormalities were over three times commoner in those reporting audiosensitivity. This relationship was stronger in older children. Intolerance to noise not strictly defined as above was not associated with reflex abnormalities. Hyperacute pure tone thresholds were associated with lowered acoustic reflex thresholds but not with audiosensitivity. Possible physiological bases for audiosensitivity are discussed.

Adolescent↗
PubMed1997

The late blink reflex response abnormality due to lesion of the lateral tegmental field.

We report on a blink reflex abnormality observed in two patients, which provides additional information on the central pathways mediating this reflex. Autopsy was performed in one patient and MRI in the other. In the first patient there was a small lesion at the dorsal middle third of the lateral tegmental field and in the second patient at the level of the dorsal lower third of the medulla oblongata. In both patients the common finding was the absence of the late response (R2) ipsilateral to the side of the lesion, while the R2 response on the unaffected side was normal regardless of the side of the supraorbital nerve stimulation. The R1 responses were normal. This type of blink reflex abnormality has not been reported before and is referred to by us as 'tegmental type' of R2 abnormality. The results led to the conclusions that: (i) the crossed and uncrossed ascending trigeminofacial connections are mediated through the lateral tegmental field; (ii) the uncrossed trigeminofacial connection originates at the level of at least the lower medulla oblongata; (iii) the contralateral R2 response is established by way of an ascending pathway, which crosses the midline at the level of at least the lower third of the medulla oblongata.

Afferent Pathways↗
PubMed1988

External sphincter dyssynergia: an abnormal continence reflex.

Some of the characteristics of detrusor-external sphincter dyssynergia were examined in 14 patients with traumatic upper motor neuron lesions within 44 weeks of injury. The sacral evoked response latencies of the male patients were shortened at any time after injury. A continence reflex could be demonstrated in most patients at any time after injury. Comparing averaged values for the group at 4-week intervals, resting pressure at the external urethral sphincter and post-void residual volumes reached nadirs at 12 weeks while voiding efficiency peaked at this time. Thus, voiding function appears to be optimal 12 weeks after injury. During reflex detrusor activity, increases in external urethral sphincter electromyographic activity and external urethral sphincter pressure were associated clearly with a positive slope of the intravesical pressure trace, whereas decreases in both parameters were associated with a negative slope. Voiding occurred only during a negative slope. Although propantheline induced detrusor areflexia, episodic peaks in external urethral sphincter pressure and electromyographic activity continued to occur. We propose that external sphincter dyssynergia, which is independent of detrusor contraction, is the continence reflex exaggerated owing to the loss of supraspinal influences. We believe that the multiple patterns of dyssynergia described previously by others are variations, largely owing to technique, of the single pattern we have observed. The observation of synergic-like urethral responses in some patients during a negative slope of the intravesical pressure, even with complete suprasacral spinal lesions, implies existence of a pathway for synergic-like voiding in the spinal cord.

Adult↗
PubMed2001

Abnormal esophagocardiac reflex in patients with non-cardiac chest pain.

As the mechanoreceptor stimulation of the esophagus activates an esophagocardiac inhibitory reflex, with possible cardiac hypokinetic arrhythmias, we investigated whether patients with non-cardiac chest pain have this reflex, which could represent a source of risk in predisposed individuals during the intraesophageal balloon distension test. Electrocardiogram readings were recorded in nine patients with non-cardiac chest pain (group A), the esophageal origin of which was diagnosed with cardiac and esophageal examinations, in 10 patients with hyperkinetic esophageal motor disorders without chest pain (group B), and in eight normal subjects used as controls (group C), after swallowing solid boluses and during intraesophageal balloon inflation at 100 mmHg for 10 s. The percent variation of the R-R interval from its mean basal value to its highest value observed after stimulation was calculated. Solid swallows induced an increase in heart rate followed by a decrease that was significantly higher in group B than group C, while group A was not significantly different from group C. Balloon inflation induced a significant decrease in heart rate in all groups, but in group A the degree of decrease was significantly lower than in groups B and C. In conclusion, esophageal wall distension, either as a result of solid bolus or balloon inflation, elicits an inhibitory esophagocardiac reflex that is higher than normal in patients with hyperkinetic esophageal motor disorders without pain and lower than normal in patients with non-cardiac chest pain of esophageal origin, who, consequently, have nothing to fear from this procedure.

Adult↗
PubMed2006

Abnormal blink reflex studies in a patient with supraorbital neuralgia.

A 44-year-old female with gabapentin-responsive supraorbital neuralgia is presented. She had pre- and post-treatment nociceptive-specific blink reflexes carried out which tracked the good clinical outcome from treatment. The results of the electrophysiological testing imply some central component to the pathophysiology of supra-orbital neuralgia.

Adult↗
PubMed1990

[Effect of abnormal gagging reflex on the possibility of aspiration in mentally retarded children].

The gag reflex promoting aspiration was examined in 262 mentally retarded (MR) children followed up for 3 years due to respiratory illnesses. It was present in 24.1% of MR children and in 91.6% in a control group of children, the difference being statistically significant. A similar significant difference was between the number of children with psychopharmaceutical treatment and the incidence of gag reflex impairment in them. The therapeutic influencing of the swallowing reflex by medicaments is contraindicated in MR children for inducing epileptic seizures. The main point is to prevent aspiration as a stimulus for respiratory disease occurrence. The most important measures are a focused attention of the staff during meals and feeding of MR children and its systematic further education concerning these problems.

Child↗