Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Blinking”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 271 records · Page 15Linked to original sources
PubMed1986

Increased blink rate in adolescent patients with psychosis.

Increased blink rate, a putative correlate of central dopaminergic activity, may be elevated in patients with chronic schizophrenia. In an effort to determine whether this elevation is due to iatrogenic factors, blinking was examined in medication-naive adolescent psychiatric inpatients undergoing their first hospitalization. The mean (+/- SD) blink rate of patients with psychosis (n = 13, 16 +/- 9 blinks/minute) was significantly greater than that of the nonpsychotic control inpatients (n = 35, 10 +/- 6 blinks/minute). Thus, elevated blink rate may be a feature of psychosis that is not necessarily caused by neuroleptic treatment or psychiatric hospitalization.

Adolescent↗
PubMedDate not supplied

Increased blink rates in schizophrenics. Influences of neuroleptics and psychopathology.

During a standardized visuomotor task, eye blinking, a possible parameter of central dopaminergic activity, was studied in 18 previously medicated and eight drug-naive schizophrenic in-patients in the acute state and during remission. Whereas schizophrenics executed the visuomotor task with the same precision as age- and sex-matched normal control subjects did, the mean blink rate was increased in both schizophrenic groups. During neuroleptic treatment, the mean blink rate was reduced only in the group of drug-naive patients, but not in the previously neuroleptic treated schizophrenics. This varying blinking activity is discussed with respect to the development of neuroleptic tolerance and influence of psychopathology.

Adult↗
PubMed2004

Cortical control of voluntary blinking: a transcranial magnetic stimulation study.

OBJECTIVE: To investigate cortical regions related to voluntary blinking. METHODS: Transcranial magnetic stimulation (TMS) was applied to the facial motor cortex (M1) and the midline frontal region (Fz) in 10 healthy subjects with eyes opened and closed. Motor-evoked potentials were recorded from the orbicularis oculi (OOC), orbicularis oris (OOR), abductor digiti minimi and tibialis anterior using surface and needle electromyography electrodes. Facial M waves and blink reflex were measured using supramaximal electrical stimulation of the facial and supraorbital nerves. RESULTS: TMS at Fz elicited 3 waves in OOC with no response in other tested muscles except for the early wave in OOR. Facial M1 stimulation produced only early and late waves. Because of their latencies, shapes, and relationship to coil position and stimulation intensity, early and late waves appeared to be analogous to the facial M wave and R1 component of the blink reflex. The intermediate wave at 6-8 ms latency was elicited in OOC by Fz stimulation with eyes closed. CONCLUSIONS: Since its latency matches the central conduction time of other cranial muscles and it has characteristic of muscle activation-related facilitation, the intermediate wave is presumably related to cortical stimulation. This result provides evidence that the cortical center for the upper facial movements, including blinking, is not principally located in the facial M1, but rather in the mesial frontal region.

Adult↗
PubMed2005

When the orbicularis oculi response to a startling stimulus is zero, the vertical EOG may reveal that a blink has occurred.

OBJECTIVE: Startle blink reflexes in humans are typically measured as orbicularis oculi electromyographic activity (ooEMG) in response to startling stimuli. When ooEMG activity cannot be measured, responses are scored as 'zero'. However, inhibition of the levator palpebrae is also involved in every blink. The present study examines whether or not during 'zero' startle responses, defined by absence of orbicularis oculi contraction, a startle blink defined by lid movement (i.e. indirect evidence of cessation of tonic levator palpebrae activity) might occur. METHODS: Both ooEMG and vertical electro-oculogram (vEOG) were recorded in 55 children and adolescents during acoustic startle stimulation. Zero ooEMG responses and their accompanying vEOG were tabulated. Fourteen participants who had 3 or more zero ooEMG responses associated with measurable vEOG responses were selected for more detailed study. RESULTS: For these 14 subjects, of 25.4% of usable trials scored as zero in ooEMG, 86.8% of these were accompanied by measurable vEOG responses (for all 55 subjects, 7.9% of trials had zero ooEMG responses, and 70.8% of these zero trials were accompanied by measurable vEOGs). Mean vEOG amplitude and peak latency were comparable whether associated with small ooEMG responses or ooEMGs scored as zero. These 14 participants had smaller and shorter ooEMG responses than the remainder of the sample, but other parameters of ooEMG and vEOG recordings did not differ. A single-case example shows how recording of ooEMG may have resulted in the decision that this participant was a putative 'startle non-responder' when concomitant recording of vEOG showed blink responding in the form of lid movement on 100% of trials. CONCLUSIONS: These results suggest that in absence of orbicularis oculi contraction, cessation of the tonic activity of the levator palpebrae can occur thereby permitting the eyelid to drop in response to an auditory startle stimulus, as measured by vEOG recordings. SIGNIFICANCE: These findings suggest that some degree of independence in the innervation of the orbicularis oculi and levator palpebrae muscle is demonstrated when the ooEMG is putatively 'zero'. This requires re-evaluation of the construct of startle response probability.

Acoustic Stimulation↗
PubMed2006

Facilitation as well as inhibition of the blink reflex by a visual prepulse requires intact striate cortex.

OBJECTIVE: The role of visual cortex in modulation of the human eye blink reflex was assessed. METHODS: Participants were 13 patients with unilateral striate cortex damage. Nonreflexogenic gratings were presented in their intact or blind hemifield prior to white noise or air puff blink-eliciting stimuli. RESULTS: Inhibition of reflex amplitude was observed at asynchronies ranging from about 120 to 600ms for visible but not invisible prepulses. Facilitation by intact-hemifield gratings was observed for (1) the latency of the acoustic blink reflex, (2) the amplitude of the disynaptic cutaneous blink reflex, R1, and (3) the latency of voluntary hand-grip reactions to the reflexogenic stimuli. These facilitatory effects were absent on trials with blind-hemifield prepulses. CONCLUSIONS: An intact V1 is required for prepulse facilitation as well as inhibition. SIGNIFICANCE: These results extend a popular model of sensorimotor gating deficits in schizophrenia.

Adolescent↗
PubMed2004

Tic disorders in children with frequent eye blinking.

PURPOSE: To prospectively evaluate the significance of psychiatric consultation in children with frequent eye blinking. METHODS: Fifty children < 16 years of age with frequent eye blinking underwent a psychiatric examination after undergoing a detailed ophthalmologic examination and receiving appropriate treatment. Patients with squinting related to intermittent exotropia or uncorrected refractive errors were excluded. The severity of tic symptoms and the differences in mothering behavior and childhood behavioral problems between the children with tic and normal children were assessed. RESULTS: Tic disorders were diagnosed in 43 children: 39 had transient tic disorders, 2 had chronic tic disorders, and 2 had Tourette's syndrome. Ten patients had complex motor tics, and 4 had motor and vocal tics. Two children with Tourette's syndrome, and another 2 who returned to the clinic with aggravated symptoms after 6 months without any ophthalmologic abnormalities, were treated with psychiatric medication. There was no difference in mothering behavior or childhood behavior problems between the children with tic and normal children. The severity of tic was significantly correlated with the duration of tic symptoms, the score of somatic complaints, and attention problems. CONCLUSIONS: Most of the children with frequent eye blinking had a transient tic disorder. Tics become more severe with a longer duration of symptoms and may have influenced the somatic symptoms and the patient's level of attention. Psychiatric consultation may be necessary for children with long-standing and frequent eye blinking.

Attention↗
PubMed2006

Reticulo-collicular and spino-collicular projections involved in eye and eyelid movements during the blink reflex.

Reflex blinking provides a useful experimental tool for various functional studies on the peripheral and central nervous system, yet the neuronal circuitry underlying this reflex is not precisely known. In the present study, we investigated as to whether neurons in the reticular formation and rostral cervical spinal cord (C1) may be involved in the blink reflex in rats. To this end we investigated c-Fos expression in these areas following supraorbital nerve stimulation combined with retrograde tracing of gold conjugated horse radish peroxidase (Gold-HRP) from the superior colliculus. We observed many double labeled neurons in the parvocellular reticular nucleus, medullary reticular formation, and laminae IV and V of C1. Thus, these brain regions contain neurons that may be involved in blink reflexes as well as eye movements, because they both can be activated following peri-orbital stimulation and project to the superior colliculus. Consequently, we suggest that the medullary reticular formation and C1 region play a central role in the coordination of eye and eyelid movements during reflex blinking.

Animals↗
PubMed2004

The effect of multiple stimuli on the modulation of the 'nociceptive' blink reflex.

The 'nociceptive' blink reflex is a method of examining human trigeminal pain pathways. We explored temporal summation of this reflex by using a train of pulses, rather than a single pulse, and remote activation of diffuse noxious inhibitory control (DNIC), to improve reliability, flexibility and nociceptive specificity of this technique. The R2 component of the nociceptive blink reflex response (nR2) was assessed in 28 healthy volunteers using between 1 and 7 pulses per stimulus train (inter-pulse interval 5 ms). The effect of DNIC on single-, double-, and triple-pulse nR2 was investigated. Compared to single pulses, double and triple pulses increased the sensation of pain, reduced the tactile and pain thresholds, and facilitated the blink reflex responses (reduced onset latency, increased magnitude and persistence of nR2). The maximal reflex facilitation was achieved using a triple pulse. Higher pulse numbers had no additional facilitatory effect. Activation of the DNIC system using heterotopic pain suppressed the nR2 evoked by double and triple stimulation by 16 and 42%, respectively, but not the nR2 from a single pulse. Stimulation with double and triple pulses may be more suitable to study influences on nociceptive pathways than single pulses and may widen the methodological flexibility of the nociceptive blink reflex technique. This technique may be useful in studying the trigeminal nociceptive system with particular reference to primary headache disorders and their neuropharmacology.

Adult↗
PubMedDate not supplied

Blink reflex and discomplete facial nerve palsy.

BACKGROUND: Electrophysiologic findings of the blink reflex in patients with Bell's palsy are usually said to be either prolonged latencies and/or absent early and middle responses of it. METHODS: Facial nerve conduction and blink reflex studies were performed on a 42-year-old male patient with right-side Bell's palsy. Studies were done using protocols previously validated and published elsewhere. RESULTS: The right compound muscle action potential was not found after stimulation of the right facial nerve as expected. Absence of the short (R1) and middle (R2) responses of the blink reflex were also noted after right and left supraorbital nerve stimulation. Further, the late (R3) response of the blink reflex was displayed on the abnormal side when electrical stimuli were applied to the right supraorbital nerve while the patient attempted to perform voluntary movement of the paralyzed facial muscles including eye closing. CONCLUSIONS: The recording of R3-a late response following fibers and using motoneurons other than those employed by R1 and R2-on the paralyzed side after performing some reinforcement maneuvers allows us to suggest that, in some facial nerve palsies, there are some structures remaining alive that may be useful for carrying out a more timely and accurate diagnosis and follow-up.

Action Potentials↗
PubMed1998

The 'geste antagonistique' induces transient modulation of the blink reflex in human patients with blepharospasm.

The mechanism of action of the 'geste antagonistique', or sensory trick, used by patients with dystonic blepharospasm (BSP) to transiently diminish their symptoms is presently unknown. In this paper we examined the effects induced by a sensory trick consisting of finger contact with the face on the electrically induced blink reflex and the blink reflex excitability recovery curve to paired stimuli. The results were compared with those obtained in a group of six healthy volunteers who mimicked the manoeuvre used by the patients as a sensory trick. In all subjects, the area of R2 was significantly reduced, and the amplitude of R1 was significantly enhanced, during a mean of 10 min after the onset of finger-face contact in comparison to rest. However, there were no changes in the blink reflex excitability recovery curve. The contact-induced effect on the magnitude of the R2 component of the blink reflex is probably caused by sensory gating on trigeminal afferents. Such a reduction in the gain of trigemino-facial reflexes may partly underly the transient benefit experienced by patients with BSP with the use of sensory tricks.

Blepharospasm↗
PubMed1988

Blink reflex in children with neurological disorders: analysis of ipsilateral early component R1 and late component R2.

The blink reflex was studied in 101 children with neurological disorders, especially with regard to alterations in the ipsilateral early component R1 and the late component R2. As a whole any kind of abnormality in the latency and/or amplitude of R1 or R2 was detectable in patients of cerebral, brainstem and peripheral lesions. There were neither specific findings with respect to localization of the lesions nor differences among each age group except for in patients of brainstem disorders. In the patients with increased intracranial pressure, the blink reflex sensitively reflected the high intracranial pressure. In motor impairment cases, even severely affected, the blink reflex was within normal range in late infancy. The blink reflex is influenced by the brain maturation, the underlying etiology and pathophysiology. R2 is more closely correlated with the clinical findings than R1.

Adolescent↗
PubMed1989

Maturation of blink reflex in children.

The blink reflex was examined in 57 subjects aged from neonate to adult in the alert state. The ipsilateral late response (R2) was elicited in all subjects and considered most suitable to evaluate maturational changes of the blink reflex. In a few subjects older than 3 years and of adults, the ipsilateral early response (R1) was difficult to observe. The contralateral late response (R2') could not be obtained in 32% of neonates and infants. From the observation about developmental change of an interference pattern, a latency shortening of R2 and a latency difference between R2' and R2, the blink reflex in children may be considered as mature at no later than 5 years of age. In addition, the R2 latency tended to increase temporarily through 1 or 2 years from late infancy. The reflex circuit evaluated by the blink reflex in children may partially change its makeup after the early infantile period and is almost fully mature at no later than 5 years.

Adolescent↗
PubMed2003

Decreased habituation of the R2 component of the blink reflex in migraine patients.

OBJECTIVE: Activation of the trigemino-vascular system as well as of brainstem trigeminal nuclei are thought to play an important role in migraine. The aim of this study was to investigate the habituation phenomenon of the blink reflex in 30 headache-free migraine patients and 30 control subjects. METHODS: An electromyographic device with a specific habituation test program was used to elicit and record blink reflex responses on both the right and left sides, and to randomly repeat the stimulations at different time intervals in order to induce habituation. RESULTS: Whereas the R1 and R2 latencies, amplitudes and areas in the basal assessment were similar in patients and control subjects, the blink reflex habituation responses were markedly reduced in migraine patients who had a migraine attack within 72 h after testing (group A). In these patients, the differences between the R2 areas, obtained when stimuli were delivered at subsequent time intervals ranging between 10-5, 5-4, 4-3 and 3-2 s, were statistically different (P<0.001) from those of the patients who had a migraine attack after a longer time interval (group B) and control subjects. CONCLUSIONS: Our data suggest that the brainstem pathways involved in the blink reflex may be activated in the premonitory phase of migraine attacks, probably through mechanisms that involve dopaminergic function.

Adult↗
PubMed1999

Bilateral centrotemporal spikes triggered by blinking: an unusual form of sensory input with related cortical EEG activity.

OBJECTIVE: To investigate the morphology, scalp topography and temporal relationship with orbicularis oculi muscle contraction of bilateral blink related spikes (BRS) in a 7-year-old boy with chromosomopathy, mild mental retardation and left spontaneous centrotemporal spikes (SS). METHODS: The patient underwent video-polygraphic recordings with off-line analysis of SS and BRS by means of spike-averaging and orbicularis oculi contraction-locked averaging techniques respectively. EEG activity related to reflex blinking (evoked by glabellar tapping) was also studied. RESULTS: SS and BRS presented the same morphology, characterised by four peaks (P1, N1, P2, N2). SS were located over the left centroparietal regions, while BRS were placed over both left and right centrotemporoparietal regions and constantly followed the contraction of orbicularis oculi with overlapping peak latencies over C3 and C4 electrodes (P1 72 ms; N1 115 ms; P2 164 ms; N2 236 ms). Reflex blinking evoked a small waveform with the same features as BRS. CONCLUSIONS: Our findings suggest that both involuntary and reflex blinking can act as a form of sensory stimulation probably engaging similar nervous pathways and cortical sources in generating EEG abnormalities: the trigeminal system.

Action Potentials↗
PubMed2003

Electromyographic assessment of blink and corneal reflexes during midazolam administration: useful methods for assessing depth of anesthesia?

BACKGROUND: There are at least three components of the anesthetic state: loss of consciousness, amnesia and obtundation of reflex responses to noxious stimuli. To investigate the third component, we used a standard electrical stimulus to evoke a blink reflex, which was electromyographically recorded. These data may give information on the anesthetic state. METHODS: The relation between the electrically evoked blink and corneal reflexes and the depth of sedation and anesthesia induced with intravenous midazolam was investigated. Ten patients received i.v. increments of midazolam (1 mg, 2 mg, 3 mg, 3 mg, 3 mg, etc., until a 21-mg total dose) to create a step-wise deepening of sedation and anesthesia. Depth of anesthesia was assessed by the Observer's Assessment of Alertness/Sedation (OAAS) scale, ranging from 5 ( = awake and alert) to 0 ( = no motor response to tetanic stimulation). RESULTS: Latency of the first (R1) and second (R2) blink components and the corneal (C) reflex component increased, whereas duration and area decreased with increasing depth of sedation and anesthesia. R1 was last seen at an OAAS score [mean (SD)] of 1.8 (0.8), R2 at a score of 3.1 (1.1), C at a score of 3.8 (0.8), and R3 at 4.8 (0.5). These end-points were all statistically different from each other, except R2 vs. C. CONCLUSIONS: Our results suggest that the differential sensitivity of the components of the blink reflex could be useful to monitor depth of sedation and light levels of anesthesia during the administration of midazolam.

Adult↗
PubMed2003

Effect of the adenosine A1 receptor agonist GR79236 on trigeminal nociception with blink reflex recordings in healthy human subjects.

GR79236 is a highly potent and selective adenosine A1 receptor agonist that has analgesic and anti-inflammatory actions in humans and animals. In animal models it inhibits trigeminal nerve firing and calcitonin gene-related peptide release which play a pivotal role in migraine pathophysiology. Thus GR79236 may have therapeutic potential in migraine. Although there are no validated human models of migraine, the trigeminal nociceptive pathways may be studied with a novel electrode to elicit nociception-specific blink reflex responses. Twelve healthy female volunteers were randomized in a double-blind, placebo-controlled, cross-over trial to investigate the effect of GR79236 on trigeminal nociceptive pathways, as measured by the blink reflex. A secondary objective was to compare the use of two types of electrode, the standard (SE) and nociception-specific electrodes (NE), to investigate human trigeminal pharmacology. Blink reflexes were elicited with SE and NE before and 30 min after GR79236 (10 microg/kg i.v.) or placebo. The median area under the curve of repeated sweeps of the R2 component of the blink reflex was analysed using analysis of covariance with baseline as covariate. Using NE, GR79236 produced a non-significant reduction of the ipsilateral R2 compared with placebo (P = 0.097) and a significant reduction contralaterally (P = 0.008). No significant changes were observed using SE. There were no significant adverse events. The results suggest that NE is more sensitive than SE to detect pharmacological effects in the trigeminal nociceptive system. Furthermore, the adenosine A1 receptor agonist GR79236 inhibits trigeminal nociception in humans. These results support a possible therapeutic role for GR79236 in primary headache disorders.

Adenosine↗
PubMed1998

Blink reflex in migraine and tension-type headache.

The blink reflex was studied in 19 patients with migraine, 10 patients with tension-type headache, and 30 healthy controls. Significantly lower values of R2 and R2' amplitude and size were found in the migraine group, compared with the healthy control group. The differences were independent of the stimulation side (headache or nonheadache) and highly significant (P<0.001). The abnormalities of R2 and R2' amplitude and size were found only during the headache phase of migraine, being normal between migraine attacks. R1 latency and amplitude were normal in all patients. The blink reflex was normal in all the patients with tension-type headache. Subcutaneous injection of sumatriptan in 10 of the 19 migraineurs, during the headache phase, restored R2 and R2' amplitude and size values to normal. Our findings indicate that the brain stem interneuron part of the blink reflex arc may be diffusely suppressed in migraine, only during the headache phase. Furthermore, blink reflex may be an objective laboratory method to monitor the effectiveness of specific drugs proposed for the treatment of migraine.

Adult↗
PubMed1990

Study of the relationship between lacrimation and blink in VDT work.

VDT (Visual Display Terminal) work generates various symptoms in operators' eyes such as strain, a sensation of dryness, the presence of a foreign body, and so on. Research suggests that lacrimal abnormality may be related causally to such symptoms. In this paper, the relationship between lacrimation (the secretion of tears) and the frequency of blink due to VDT work in health subjects and VDT workers with such symptoms, and consequent therapeutic methods, were studied. When lacrimation, BUT (Break-UP Time), and the frequency of blink before and after VDT work compared in the control subjects and VDT-operators, an essential difference was noted in experiment 1 the frequency of blink decreased only during VDT operation, and a decreasing tendency of lacrimation was also noted while lacrimation before operation was already less in the VDT group; no large variation was noted before or after VDT operation. The frequency of blink was relatively high during operation, and a decreasing tendency of BUT was noted, compared with that for control subjects. In experiment 2, lacrimation increased remarkably in four eyes (of two operators), and relief from the subjective symptoms was noted. However, BUT intactly reduced similarly before the use of a gelatin rod during the whole process. The insertion of a gelatin rod was consecutively carried out every two weeks for approximately eight months; the development of complications such as dacryosolenitis, etc., was not noted. From these results, it is considered that the insertion of a gelatin rod is clinically useful for VDT operators with decreasing lacrimation.

Adult↗