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At least 793 records · Page 44Linked to original sources
PubMed1992

Human startle reflex: technique and criteria for abnormal response.

Because quantitative norms for the normal audiogenic startle response to repeated stimuli have not been previously reported, we now describe a technique for eliciting the startle response and analysing its habituation with repeated stimuli. We used binaural 105 dB tones delivered in 5 blocks of 4 tones. Successive blocks were separated by a 5 min period without tones stimuli and had progressively shorter inter-stimulus intervals (ISIs) beginning with 5 min in the first block and reducing to 1 min in the final, fifth block. We contrast the response and its habituation in a group of 8 normal subjects with that in a patient with clinically exaggerated startle. Based on the differences observed, we propose that the following criteria may be used to ascertain an abnormally increased startle response: (1) excessive duration of the myogenic response; (2) persistence of extracranial responses after the initial two blocks of stimuli; and (3) reduced habituation of the response (as measured by decreases in response duration and in the area under the curve of rectified EMG for the orbicularis oculi myogenic response). Our patient was abnormal on each of these measures. This result is consistent with past qualitative reports which have indicated that abnormal startle is associated both with excessive startle and with subnormal habituation. Study of further patients with hyperekplexia will be necessary to either confirm our data or modify our proposed criteria.

Acoustic Stimulation↗
PubMed1998

Role of the masseter reflex in the assessment of subacute sensory neuropathy.

In 3 patients with a severe pure sensory neuropathy of subacute onset, the masseter reflex remained normal despite absent blink reflex responses and absent stretch reflexes in the extremities. In 20 patients with primary disorders of peripheral nerve axons or myelin, the masseter reflex was abnormal. This study suggests that a normal masseter reflex in patients presenting with a pure sensory neuropathy favors a polyganglionopathy rather than a primary axonal sensory neuropathy, particularly if the blink reflex is abnormal.

Blinking↗
PubMed1996

Auditory performance and acoustic reflexes in young adults reporting listening difficulties.

We aimed to determine whether reported difficulties in speech understanding are associated with abnormal acoustic reflex thresholds (ARTs). The acoustic reflex has been shown to have a role in the understanding of speech at high intensities by ensuring that the strong low-frequency components of sound do not excessively mask the higher-frequency components, which are important for speech understanding. There is also wide variance in individual ARTs. Hence, the possibility arises that subjects reporting listening difficulties in noise have abnormal acoustic reflex function. In this investigation, a questionnaire to 2395 university students was used to obtain 20 subjects reporting listening difficulties in background noise and requesting advice about their hearing problems; it also screened out significant histories of middle ear disease in childhood. These subjects, and 20 control subjects reporting no listening difficulties, received a battery of performance tests and measures of acoustic reflex thresholds. Results showed significant differences in auditory performance between subjects reporting listening difficulties and those with no such difficulties, but no differences in acoustic reflex thresholds. These findings extend the relationship between reported listening difficulties and auditory performance within the "normal hearing' range, but this relationship is unlikely to be due to abnormal acoustic reflex thresholds.

Auditory Threshold↗
PubMed1992

Oculomotor, auditory, and vestibular responses in myotonic dystrophy.

In 13 patients with myotonic dystrophy, oculomotor, auditory, and vestibular tests were performed. All 13 patients showed one or more abnormalities. There was a significant increase in the penetrance of the separate abnormalities with age. Saccadic slowing was found in 10 patients, in a severe form in three. Seven patients had a sensorineural high-tone hearing loss (30 to 85 dB at 8 kHz), which was in excess of that expected for their age, that could be attributed to myotonic dystrophy. Brain-stem auditory evoked potentials showed a significant interwave delay of the I-V interval (0.35 to 0.7 milliseconds). An abnormal vestibulo-ocular reflex was found in six patients; three had vestibular hyperreflexia with increased gain, and three had hyporeflexia with short time constants. This study confirms that in myotonic dystrophy, sensory system involvement can be found on both a peripheral and a central level.

Adolescent↗
PubMed1995

The "4A" syndrome: adrenocortical insufficiency associated with achalasia, alacrima, autonomic and other neurological abnormalities.

The triad of adrenocortical insufficiency with alacrima and achalasia is an unusual disease entity in paediatrics. The association of autonomic and peripheral neuropathies has more commonly been reported in older individuals. We describe four children (two siblings) with this disorder, aged between 3 and 6 years at diagnosis, all of whom had clinical neurological abnormalities when examined between 6 and 8 years of age. In addition, we performed cardiovascular autonomic testing in three subjects: heart rate variation during deep breathing was abnormal in all three; Valsalva ratio was abnormal in two; and postural systolic blood pressure response was abnormal in one. Pupillary reflexes were abnormal in the only subject in which they could be measured. These results indicate that subtle neurological and, in particular, autonomic abnormalities can be detected at an early age. We propose that autonomic neuropathy be considered as an integral feature of this rare condition and suggest the term "4A" syndrome as a useful mnemonic for the association of adrenocortical insufficiency, achalasia and alacrima with autonomic and other neurological abnormalities.

Adrenal Cortex Function Tests↗
PubMed1991

[Significance of the blink reflex in the Wallenberg syndrome].

The blink reflex was studied in 38 cases with lateral medullary lesions (Wallenberg syndrome). Twenty-one blink reflexes were abnormal. The most common abnormality is an afferent delay in the late reflex on the side of the lesion with a normal early reflex. This abnormality is not pathognomonic of the Wallenberg syndrome. The physiopathogeny is discussed.

Adult↗
PubMed1995

Abnormalities in gallbladder dynamics of type 1 (insulin-dependent) diabetic patients with autonomic neuropathy.

The aim of this study was to evaluate gallbladder dynamics in insulin-dependent diabetic patients with and without autonomic neuropathy. Gallbladder dynamics was studied by a scintigraphic method after a test meal in 26 insulin-dependent diabetic patients and 10 normal individuals. The presence and severity of autonomic neuropathy were defined according to the number of abnormal cardiovascular reflex tests: absent (no abnormal test), mild (1-3 abnormal tests), and severe (4-5 abnormal tests). The time from the moment when the patient started to take the test meal to the beginning of gallbladder emptying was longer (P = 0.01) in diabetic patients with mild (N = 11, 12.1 +/- 7.6 min) and severe neuropathy (N = 8, 11.0 +/- 10.6 min) than diabetic patients without autonomic neuropathy (N = 7, 3.9 +/- 4.4 min) and controls (N = 10, 4.8 +/- 4.2 min). The ejection rate was higher (P = 0.02) in the group with severe autonomic neuropathy (N = 8, 5.1 +/- 3.3%/min) than diabetic patients with mild (N = 11, 2.0 +/- 1.0%/min) or without autonomic neuropathy (N = 7, 1.8 +/- 0.8%/min) and controls (N = 10, 2.6 +/- 1%/min). Thirty-two percent of the diabetic patients with autonomic neuropathy presented increased perspiration, nausea and urgency to defecate after the ingestion of the test meal. A significant positive correlation of ejection rate with the presence of these symptoms (biserial point correlation test = 0.67, P < 0.01) was also observed. These data suggest that insulin-dependent diabetic patients with autonomic neuropathy present abnormalities of gallbladder emptying that could be related to specific gastrointestinal symptoms.

Adult↗
PubMed1987

Predictive criteria for failed sphincterotomy in spinal cord injury patients.

Nine patients with chronic high spinal cord injury who failed sphincterotomy secondary to detrusor hypocontractility underwent neurourological evaluation. Testing revealed an abnormality involving the sensory limb of the somatic sacral reflex arc (abnormal R wave) or at the level of the spinal interneuron pool (abnormal or absent S wave). This study strongly suggests that the sensory input from the bladder to the spinal cord, together with alteration in the sensory motor integration that occurs at the level of the interneuron pool, is important in influencing the characteristics of the detrusor contraction following high spinal cord injury. Predictive criteria for failed sphincterotomy are a slow increase to maximum intravesical pressure before voiding and abnormal lumbosacral sensory evoked potentials.

Adolescent↗
PubMed1996

The significance of an absent ankle reflex.

We assessed the prevalence of abnormal ankle reflexes in 1074 adult patients attending orthopaedic clinics and related it to age. Those with possible pathological causes of reflex loss were excluded. The absence of one or both reflexes was significantly related to increasing age; all patients under 30 years had both reflexes. Few had absent reflexes between 30 and 40 years, but over 40 years, the proportion with both reflexes absent increased rapidly from 5% (40 to 50 years) to 80% (90 to 100 years). Unilateral absence did not show the same pattern of increase being 3% to 5% at 40 to 60 years and 7% to 10% at over 60 years. Our results suggest that a significant number of 'normal' adults have unilateral absence of an ankle reflex, but this finding is rare enough to be a definite clinical sign, irrespective of age.

Adolescent↗
PubMed1994

[Abnormal evoked EMG and blink reflex responses in patients with hemifacial spasm (HFS)].

Abnormal evoked EMG and blink reflex responses have been observed on the affected side in patients with HFS. These characteristic responses were used as methods of preoperative differential diagnosis, and the disappearance of these abnormal responses during intraoperative monitoring was assessed as confirmation of nerve decompression. The subjects were 30 patients with a diagnosis of HFS. Three responses were evaluated: 1) the orbicularis oris muscle (OR) response to stimulation of the orbicularis oculi muscle branch (OB), OB-->OR; 2) the orbicularis oculi muscle (OC) response to stimulation of the marginal mandibular branch (MB), MB-->OC; and 3) the (OR) response to stimulation of the supraorbital nerve (SO), SO-->OR. The facial nerve in the root exit zone was compressed by a vessel in all 21 patients diagnosed as typical HFS who had abnormal responses, and OB-->OR was always detected. The MB-->OC and SO-->OR detection rates were low (50% and 25%, respectively) when the interval since the onset of HFS was less than 3 years, but increased to 78% and 67%, respectively, when it was 3 to 5 years, and all three abnormal responses were always detected when the interval was more than 5 years. In 17 of the patients these responses began to change and eventually disappeared before decompression of the facial nerve, and in 2 patients they persisted even after decompression. Abnormal responses disappeared at the time of decompression in only 2 patients, and their HFS was completely cured postoperatively. These findings confirmed that disappearance of abnormal responses is not a very useful guide for facial nerve decompression.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗