Differences In Pupillary Responses Research Articles

Emotional arousal in patients with functional movement disorders: A pupillometry study

ObjectivePathophysiology explanations for functional movement disorders often assume a role for emotional hyperarousal. Pupillometry is a validated method for evaluation of emotional arousal by detecting changes in pupil size in response to emotional stimuli. In a case-control study design, we aimed to study objective and subjective emotional arousal using pupillometry and affective ratings. To assess attentional engagement by affective stimuli, we used videooculographic tracking of eye movement patterns (scanpath). MethodsTwenty-five female patients with functional movement disorders (mean age: 40.9 [SD 12.7] years) and 23 age matched healthy female controls participated in the study. Using infrared high-resolution eye-tracker, both pupil size and eye movement pattern in response to emotionally charged erotic, adventure, threat, victim, and neutral pictures were recorded along with subjective ratings of emotional valence and arousal of the presented pictures. ResultsA between-group comparison showed significantly smaller pupil dilation to adventure stimuli compared to neutral stimuli in patients compared to controls (P < 0.004, bootstrap, uncorr., adj. η2 = 0.00). No significant difference in pupillary response to other stimuli and scanpath parameters was found between the groups. Patients rated significantly lower emotional arousal to erotic pictures than controls (P < 0.001, bootstrap, uncorr., adj. η2 = 0.09). ConclusionThis study did not find evidence of autonomous or subjective emotional hyperarousal. The mismatch between objective autonomic measures and subjective arousal ratings in patients is of pathophysiological interest and in line with recent findings of impaired interoception in functional movement disorders.

A pupillometry study of multisensory social and linguistic processing in autism and typical development.

Autism spectrum disorder is a neurodevelopmental disorder that is characterized by impairments in social communication, restricted interests, and repetitive behaviors. Many studies have demonstrated atypical responses to audiovisual sensory inputs, particularly those containing sociolinguistic information. It is currently unclear whether these atypical responses are due to the linguistic nature of the inputs or the social aspect itself. Further, it is unclear how atypical sensory responses to sociocommunicative stimuli intersect with autism symptomatology. The current study addressed these outstanding questions by using pupillometry in mental age-matched children with and without autism (N = 71) to examine physiological responses to dynamic, audiovisual stimuli including social, sociolinguistic, socioemotional, and nonsocial stimuli, as well as to temporally manipulated stimuli. Data revealed group differences in pupillary responses with social stimuli but not nonsocial stimuli and, importantly, showed no variation through the inclusion of linguistic or emotional information. This suggests that atypical sensory responses are driven primarily by the inclusion of social information broadly. Further, individual responses to social stimuli were significantly correlated with a wide range of autism spectrum disorder symptomatology, including social communication, restricted interests and repetitive behaviors, and sensory processing issues. Pupillary responses to social but not nonsocial presentation were also capable of predicting diagnosis with a high level of selectivity, but only with marginal sensitivity. Finally, responses to the temporal manipulation did not yield any group differences, suggesting that while atypical multisensory temporal processing has been well documented in autism at the level of behavior and perception, these issues may be intact at the physiological level. (PsycInfo Database Record (c) 2020 APA, all rights reserved).

Uncharacteristic Task-Evoked Pupillary Responses Implicate Atypical Locus Ceruleus Activity in Autism.

Autism spectrum disorder (ASD) is characterized partly by atypical attentional engagement, reflected in exaggerated and variable responses to sensory stimuli. Attentional engagement is known to be regulated by the locus ceruleus (LC). Moderate baseline LC activity globally dampens neural responsivity and is associated with adaptive deployment and narrowing of attention to task-relevant stimuli. In contrast, increased baseline LC activity enhances neural responsivity across cortex and widening of attention to environmental stimuli regardless of their task relevance. Given attentional atypicalities in ASD, this study is the first to evaluate whether, under different attentional task demands, individuals with ASD exhibit a different profile of LC activity compared with typically developing controls. Males and females with ASD and age- and gender-matched controls participated in a one-back letter detection test while task-evoked pupillary responses, an established correlate for LC activity, were recorded. Participants completed this task in two conditions, either in the absence or presence of distractor auditory tones. Compared with controls, individuals with ASD evinced atypical pupillary responses in the presence versus absence of distractors. Notably, this atypical pupillary profile was evident despite the fact that both groups exhibited equivalent task performance. Moreover, between-group differences in pupillary responses were observed specifically in response to task-relevant events, providing confirmation that the group differences most likely were specifically associated with distinctions in LC activity. These findings suggest that individuals with ASD show atypical modulation of LC activity with changes in attentional demands, offering a possible mechanistic and neurobiological account for attentional atypicalities in ASD.SIGNIFICANCE STATEMENT Individuals with autism spectrum disorder (ASD) exhibit atypical attentional behaviors, including altered sensory responses and atypical fixedness, but the neural mechanism underlying these behaviors remains elusive. One candidate mechanism is atypical locus ceruleus (LC) activity, as the LC plays a critical role in attentional modulation. Specifically, LC activity is involved in regulating the trade-off between environmental exploration and focused attention. This study shows that, under tightly controlled conditions, task-evoked pupil responses, an LC activity proxy, are lower in individuals with ASD than in controls, but only in the presence of task-irrelevant stimuli. This suggests that individuals with ASD evince atypical modulation of LC activity in accordance with changes in attentional demands, offering a mechanistic account for attentional atypicalities in ASD.

Is There Any Difference in Human Pupillary Reaction When Different Acupuncture Points Are Stimulated?

To determine if there is any difference in pupillary response among different acupuncture stimulation sites. The subjects were 14 healthy males who had no known eye diseases or abnormality in their pupils. They received five different interventions: no acupuncture stimulation (hereinafter 'no-stimulation') and acupuncture stimulation at four sites (TE5, ST7, CV12 and ST36). The Latin square design was used to allocate stimulation order. For all acupuncture stimulation interventions, a disposable acupuncture needle was inserted superficially at the acupuncture point. Gentle repetitive tapping stimulation was applied manually during the subject's exhalation phase of respiration, for 90 s. The pupil diameter was continuously measured for 2 min before stimulation, during stimulation and for 2 min after stimulation. Statistical analysis was conducted on serial changes in pupil diameter during acupuncture stimulation on each respective site and during non-stimulation session by analysis of variance and Fisher (least significant difference) multiple comparison, with linear analysis using a mixed model. Pupil diameter reduction occurred at 30 s after stimulation on ST7 (p=0.008) and 60 s after stimulation (p=0.014) compared with pre-stimulation. The decrease of pupillary diameter occurred 60 s after stimulation on TE5 (p=0.028) compared with pre-stimulation. On ST36, CV12 and during the non-stimulation intervention, no significant change in the pupil diameter was observed. Pupillary reaction varies depending on the different stimulation sites.

Pupillary Reactivity to Emotional Information in Child and Adolescent Depression: Links to Clinical and Ecological Measures

Pupil dilation provides a quantitative index of the temporal pattern of brain reactivity to emotional stimuli. Previous reports indicate that depressed adults show sustained pupil dilation to emotional words, but this phenomenon has not been investigated in children. This study investigated pupil dilation in children with depression and examined how differences in pupillary responses to emotional stimuli correlate with self-rated emotional experiences in participants' natural environments in everyday life. Participants were 20 children with major depressive disorder and 22 comparison children ages 8-17. Pupil dilation was measured during a valence identification task. Participants also rated positive and negative affect in their natural environments as part of an ecological momentary assessment protocol. Children showed greater pupil dilation to negative words than to neutral or positive words. Children with major depression had diminished late pupil dilation relative to comparison children 9-12 sec after a negative word was presented. Diminished late pupil dilation to negative words was associated with greater severity of depression and with higher levels of negative affect and lower levels of positive affect in the natural environment. Depressed children exhibit a dynamic change in cognitive-affective resources devoted to processing negative emotional words, with more dramatic decreases than in comparison children after a negative word is initially processed, a pattern that differs markedly from that observed in depressed adults. Diminished late pupil dilation in children with major depression could be a marker for problems in emotional reactivity and/or regulation associated with pediatric depression.

Pupil signs of sympathetic autonomic neuropathy in patients with type 1 diabetes.

Pupillary autonomic neuropathy is considered an early sign of the development of systemic autonomic neuropathy. Sympathetic denervation is related to the duration of diabetes and the development of systemic autonomic dysfunction. We investigated pupil responsiveness to directly and indirectly acting sympathomimetics in type 1 diabetic patients with and without long-term complications, defined as cardiac autonomic neuropathy (CAN), peripheral sensomotor neuropathy, retinopathy, and nephropathy, and in healthy subjects. A total of 47 randomly chosen type 1 diabetic patients and 20 healthy subjects were selected for this study. Patients were divided into groups determined by whether they had long-term diabetic complications. Pharmacological tests were performed with cocaine 4%, epinephrine 1%, and pholedrine 5% eye drops. Horizontal pupil diameter (HPD) was measured at the beginning of the pharmacological tests and at defined time points after instillation of the eye drops. Statistical analysis showed a significantly smaller HPD in the patients before instillating eye drops (P = 0.011). In particular, the HPD was significantly smaller in the patient group without CAN when compared with healthy subjects (P = 0.004). Maximal cocaine reaction was diminished in the complication group (P < 0.001). Epinephrine test, visual acuity, ocular pressure, and HbA(1c) did not differ in patients with or without long-term complications. The noncomplication group showed no significant differences in pupillary responses as compared with healthy subjects. The complication group showed a smaller HPD (P = 0.022), reduced pupillary responses in the cocaine (P = 0.037) and pholedrine tests (P < 0.001), and anisocor pupil sizes after instillation of the eye drops (P = 0.034). Our results clearly show that sympathetic denervation does exist in the pupil of diabetic patients and that it can be rapidly assessed using the cocaine test. These data and the results of the epinephrine test suggest a mixed pre- and postganglionic dysfunction of the sympathetic plexus. The significant smaller HPD in patients without CAN compared with that of healthy subjects could be a sign for early involvement of the pupil function before cardiac manifestation of systemic autonomic diabetic neuropathy.

Pupillary response to topical tropicamide as a marker for Alzheimer's disease.

The mydriatic response to eyedrops of the anticholinergic drug tropicamide at very low concentration (0.01%) was studied in subjects with Alzheimer's disease (AD, n = 10) and multi-infarct dementia (MID, n = 10). There was no significant difference in pupillary response between the two groups. The test is unlikely to be useful in differentiating different types of dementia.

New markers for type A behavior: pupil size and platelet epinephrine.

This study tested the hypothesis that the Type A behavior pattern and its components are associated with increased activity of the sympathetic nervous system. To do this, we employed two new markers of sympathetic tone--pupil size and platelet catecholamine content. Thirty-three healthy males were blindly rated for Type A behavior and verbal stylistic components by Structured Interview. Adrenergic tone to the pupils was assessed from pupil diameter recorded by infrared television pupillometry, and pupil alpha-adrenergic sensitivity was estimated from mydriatic response to ophthalmic phenylephrine. Platelet epinephrine and norepinephrine contents were assayed because these levels are associated with chronic, long-term circulating catecholamine levels. The results showed Type As had consistently larger pupil diameters than Type Bs (p = 0.03, 0.03, and 0.01). There was no difference in pupillary response to phenylephrine instillation between groups. Platelet epinephrine content was greater in Type A subjects (chi 2 = 4.25, p less than 0.04, t = 1.6, p = 0.06). Only the component of explosiveness was modestly associated with resting pupil size, and no components significantly predicted platelet catecholamines. We conclude that the results of these two new markers of autonomic activity, namely, pupil size and platelet epinephrine, suggest that Type A behavior is characterized by increased sympathetic nervous system tone although we cannot rule out the possibility of decreased activity of the parasympathetic nervous system.

Pupillary responses to pictures and descriptions of sex-stereotyped stimuli.

An attempt was made to replicate Hess and Polt's (1960) report of sex differences in pupillary responses to sex-stereotyped pictures. Some methodological refinements were used that seem desirable for future studies. College men and women were either shown or told they would be shown pictures of a semi-nude man, a semi-nude woman, a baby, and a landscape. With resting pupil size as covariate, a three-factor analysis of covariance did not show sex differences in response to visually presented stimuli. Men responded more to verbal than visual mode of presentation and more than women to verbal stimuli. Contrary to previous results, men responded as much or more than women to verbal or visual presentation of baby stimuli. The verbal or anticipatory mode seems to be at least as sensitive as the visual and eliminates problems of control of visual materials.