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Blinking and Looking: An Eye-Tracking Approach to Studying Cognitive Processing Differences in Individuals with Speech, Language, and Communication Disorders
Published in Stavros Hatzopoulos, Andrea Ciorba, Mark Krumm, Advances in Audiology and Hearing Science, 2020
Jennifer M. Roche, Schea N. Fissel
Pupillometry is fully non-volitional and involves measurement of pupil diameter (see Fig. 4.3 for an example). Similar to endogenous blinking behavior, increased pupil dilation allows the eyes to receive more visual input. However, pupil dilation, and this measure, are thought to reflect processing load relative to decision making. Pupil dilation is not always attached to visual stimulus processing; there have been results linking pupil dilation to auditory processing load. For instance, Engelhardt et al. (2009) found that when listeners heard prosodic variation (e.g., tone of voice) that conflicted with the sentence semantics, pupil diameter increased. Zekveldet al. (2011) also found larger pupil diameters in aging individuals with hearing loss when they processed speech in noise, indicating an increase in perceptual demands required for perceptual speech processing. Pupil dilation is a highly sensitive measure and requires careful consideration and planning for valid measurement. Pupil dilation is very sensitive to illumination of visual stimuli, general lighting features of the environment (luminescence), as well as carry-over effects from previously shown/seen visual stimuli; it is very important for researchers to control the visual environment when collecting pupillometry data. Stable fixations (>300 ms) on a researcher-defined AOI are also required to achieve accurate measurements of pupil dilation.
Trauma principles
Published in Alexander Trevatt, Richard Boulton, Daren Francis, Nishanthan Mahesan, Take Charge! General Surgery and Urology, 2020
Rapid neurological assessment should be performed to assess: Consciousness level: Using GCS All patients with a significant reduction in GCS (<13) as a result of head injury should undergo a CT head to look for evidence of contusion and exclude haemorrhage.Document the GCS breakdown (eyes, voice and motor response) to aid early identification of deterioration. See Chapter 22 on how to calculate the GCS.Pupils: Size, symmetry and reaction Pupil dilation or asymmetry, with impaired or absent light reflexes may indicate an expanding intracranial bleed. An urgent CT head is necessary and prompt referral to neurosurgeons if the diagnosis is confirmed as they may require emergency surgery to reduce the pressure effect. Document clearly any discussions with the neurosurgeons and advice given.
Adrenergic Agonists
Published in Sahab Uddin, Rashid Mamunur, Advances in Neuropharmacology, 2020
Phenylephrine is an α1 selective receptor agonist used as a mydriatic and nasal decongestant in various ophthalmic and nasal formulations. The pharmacological activities produced are identical to methoxamine and produce arterial vasoconstriction (Brunton et al., 2011). Phenylephrine activates α1 receptors which result in contraction of the smooth muscles producing vasoconstriction; increased BP and vascular resistance. Ocular administration causes iris dilator muscle to constrict resulting in pupil dilation (mydriasis). Nasal decongestion, ocular decongestion, mydriasis during an ophthalmo-logical examination, maintenance of BP during surgery, treating drug-induced, and neurogenic shock (Katzung et al., 2014). It is adequately absorbed after oral or topical administration. It is administered by oral, topical and parenteral routes. It is partly metabolized by MAO in intestine and liver (Brunton et al., 2011; Stevens et al., 2008; Florey, 2008).
Continuous Curvilinear Capsulorhexis – A Practical Review
Published in Seminars in Ophthalmology, 2022
A major requisite for successful cataract surgery is a widely dilated pupil. Operating through a small pupil decreases visualization and poses a risk of complications.4,22 Pupil dilation is achieved pharmacologically with anticholinergics, sympathomimetics, and non-steroidal anti-inflammatory drugs (NSAIDs), e.g., tropicamide, cyclopentolate, phenylephrine and diclofenac.4,22,47 It can also be achieved mechanically using an OVD.22,47 Moderate dilation to 4 mm may be sufficient,5,47 as it is possible to make a CCC that is slightly larger than the pupillary diameter.47 A centrally directed tearing motion during CCC will slightly tilt the capsule so that the tearing area can be visualized.16 The iris can also gently be manipulated with a second tool to increase visibility. With experience, the surgeon can complete the task even without directly seeing the flap.6 If pupillary dilation is still insufficient despite pharmacologic dilation and OVD use, the iris can be stretched using hooks, retractors, or a pupil expansion ring.47,48 Expansion rings are preferable in cases of intraoperative floppy iris syndrome (IFIS) since they hold the pupil mechanically and prevent intraoperative miosis.22 These measures should be applied with caution as they might increase the risk of inflammation and damage to the pupillary sphincter.22,47,48
Sex Differences in Sexual Arousal and Finger Length Ratio
Published in The Journal of Sex Research, 2022
Luke Holmes, Tuesday M. Watts-Overall, Erlend Slettevold, Dragos C. Gruia, Gerulf Rieger
Additionally, we note that the sexual response patterns found in pupil dilation did not fully reflect those found in genital arousal, and that for one variable (pupil dilation to the less-arousing sex), the sex difference was in the opposite direction to that predicted (Figure 2b). While genital arousal is a well-evidenced measure of sexual arousal (Janssen, 2002; Suschinsky et al., 2009), pupil dilation is comparatively newer and has a smaller body of associated evidence. In some studies it has produced results which match with those found through genital arousal (Rieger et al., 2015), but in others it has produced results which are not fully identical to genital arousal patterns (Watts et al., 2018). Because pupil dilation indicates not only sexual arousal, but also emotion, cognition, or non-sexual interest in stimuli (Bradley et al., 2008; Goldinger & Papesh, 2012), it is likely that for some participants, pupillary responses were driven by factors other than sexual interest. Despite this limitation, the present unexpected finding that men showed greater pupil dilation to their more-arousing sex than women is still in line with the general observation that men, unlike women, respond more strongly to one sex than the other.
Systematic review of light exposure impact on human circadian rhythm
Published in Chronobiology International, 2019
Leena Tähkämö, Timo Partonen, Anu-Katriina Pesonen
Given the scope of collected data from the 128 studies in the literature review, several limitations can be identified among the studies. First, the sample size was small in many studies: 39 studies out of 128 used sample size of 10 or less subjects. Second, the pupil size was controlled or measured only in very few studies. Pupil dilation is a way to control the pupil size. When the interest is in the impacts of light exposure in typical living environments, the pupil should not be dilated, as it is likely to exaggerate the results. Third, many studies did not indicate where the light level was measured. The light level should be measured at the eye level, that is cornea, when eyes are open. Fourth, part of the studies did not clearly state the status of the eyes during the exposure. The eyelid acts as a red-pass filter (Zeitzer et al. 2014) and transmits only approximately 3%–14% of light (Robinson et al. 1991) in a wavelength-dependent manner. Thus, the retinal exposure of light depends on the status of the eyes (open, closed). Fifth, many studies failed to indicate the spectral characteristics of the exposure in an accurate manner. This would require a presentation of SPD, the wavelength, or the peak wavelength with bandwidth. Overall, it is necessary that the intensity, spectral and temporal characteristics of the exposure are accurately and clearly expressed together with the qualities of the subjects, including age, status of eyes, pupil size, length and pattern of baseline period prior to exposure, and sleep pattern (sleep deprivation or habitual sleeping rhythm).