Mechanisms of visual working memory processing task-irrelevant information retrieved from visual long-term memory.

Visual working memory (VWM) can selectively filter task-irrelevant information from incoming visual stimuli. However, whether a similar filtering process applies to task-irrelevant information retrieved from visual long-term memory (VLTM) remains elusive. We assume a "resource-limited retrieval mechanism" in VWM in charge of the retrieval of irrelevant VLTM information. To make a comprehensive understanding of this mechanism, we conducted three experiments using both a VLTM learning task and a VWM task combined with pupillometry. The presence of a significant pupil light response (PLR) served as empirical evidence that VLTM information can indeed make its way into VWM. Notably, task-relevant VLTM information induced a sustained PLR, contrasting with the transient PLR observed for task-irrelevant VLTM information. Importantly, the transience of the PLR occurred under conditions of low VWM load, but this effect was absent under conditions of high load. Collectively, these results show that task-irrelevant VLTM information can enter VWM and then fade away only under conditions of low VWM load. This dynamic underscores the resource-limited retrieval mechanism within VWM, exerting control over the entry of VLTM information.

Attentional Bias, Pupillometry, and Spontaneous Blink Rate: Eye Characteristic Assessment Within a Translatable Nicotine Cue Virtual Reality Paradigm.

Background: Incentive salience processes are important for the development and maintenance of addiction. Eye characteristics such as gaze fixation time, pupil diameter, and spontaneous eyeblink rate (EBR) are theorized to reflect incentive salience and may serve as useful biomarkers. However, conventional cue exposure paradigms have limitations that may impede accurate assessment of these markers. Objective: This study sought to evaluate the validity of these eye-tracking metrics as indicators of incentive salience within a virtual reality (VR) environment replicating real-world situations of nicotine and tobacco product (NTP) use. Methods: NTP users from the community were recruited and grouped by NTP use patterns: nondaily (n=33) and daily (n=75) use. Participants underwent the NTP cue VR paradigm and completed measures of nicotine craving, NTP use history, and VR-related assessments. Eye-gaze fixation time (attentional bias) and pupillometry in response to NTP versus control cues and EBR during the active and neutral VR scenes were recorded and analyzed using ANOVA and analysis of covariance models. Results: Greater subjective craving, as measured by the Tobacco Craving Questionnaire-Short Form, following active versus neutral scenes was observed (F1,106=47.95; P<.001). Greater mean eye-gaze fixation time (F1,106=48.34; P<.001) and pupil diameter (F1,102=5.99; P=.02) in response to NTP versus control cues were also detected. Evidence of NTP use group effects was observed in fixation time and pupillometry analyses, as well as correlations between these metrics, NTP use history, and nicotine craving. No significant associations were observed with EBR. Conclusions: This study provides additional evidence for attentional bias, as measured via eye-gaze fixation time, and pupillometry as useful biomarkers of incentive salience, and partially supports theories suggesting that incentive salience diminishes as nicotine dependence severity increases.

Pupil dilation reflects covert familiar face recognition under interocular suppression.

In prosopagnosia, brain lesions impair overt face recognition, but not face detection, and may coexist with residual covert recognition of familiar faces. Previous studies that simulated covert recognition in healthy individuals have impaired face detection as well as recognition, thus not fully mirroring the deficits in prosopagnosia. We evaluated a model of covert recognition based on continuous flash suppression (CFS). Familiar and unfamiliar faces and houses were masked while participants performed two discrimination tasks. With increased suppression, face/house discrimination remained largely intact, but face familiarity discrimination deteriorated. Covert recognition was present across all masking levels, evinced by higher pupil dilation to familiar than unfamiliar faces. Pupil dilation was uncorrelated with overt performance across subjects. Thus, CFS can impede overt face recognition without disrupting covert recognition and face detection, mirroring critical features of prosopagnosia. CFS could be used to uncover shared neural mechanisms of covert recognition in prosopagnosic patients and neurotypicals.

Quantitative pupillometry as a biomarker for prediction of return to play in mild traumatic brain injury: a Military Traumatic Brain Injury Initiative study.

OBJECTIVE: This study aimed to determine the validity of quantitative pupillometry to predict the length of time for return to full activity/duty after a mild traumatic brain injury (mTBI) in a cohort of injured cadets at West Point. METHODS: Each subject received baseline (T0) quantitative pupillometry, in addition to evaluation with the Balance Error Scoring System (BESS), Standardized Assessment of Concussion (SAC), and Sport Concussion Assessment Tool 5th Edition Symptom Survey (SCAT5). Repeat assessments using the same parameters were conducted within 48 hours of injury (T1), at the beginning of progressive return to activity (T2), and at the completion of progressive return to activity protocols (T3). Pupillary metrics were compared on the basis of length of time to return to full play/duty and the clinical scores. RESULTS: The authors' statistical analyses found correlations between pupillometry measures at T1, including end-initial diameter and maximum constriction velocity, with larger change and faster constriction predicting earlier return to play. There was also an association with maximum constriction velocity at baseline (T0), predicting faster return to play. CONCLUSIONS: The authors conclude that that pupillometry may be a valuable tool for assessing time to return to duty from mTBI by providing a measure of baseline resiliency to mTBI and/or autonomic dysfunction in the acute phase after mTBI.

Pupillary Responses to Dynamic Negative Versus Positive Facial Expressions of Emotion in Children and Parents: Links to Depression and Anxiety.

Witnessing emotional expressions in others triggers physiological arousal in humans. The current study focused on pupil responses to emotional expressions in a community sample as a physiological index of arousal and attention. We explored the associations between parents' and offspring's responses to dynamic facial expressions of emotion, as well as the links between pupil responses and anxiety/depression. Children (N = 90, MAge = 10.13, range = 7.21-12.94, 47 girls) participated in this lab study with one of their parents (47 mothers). Pupil responses were assessed in a computer task with dynamic happy, angry, fearful, and sad expressions, while participants verbally labeled the emotion displayed on the screen as quickly as possible. Parents and children reported anxiety and depression symptoms in questionnaires. Both parents and children showed stronger pupillary responses to negative versus positive expressions, and children's responses were overall stronger than those of parents. We also found links between the pupil responses of parents and children to negative, especially to angry faces. Child pupil responses were related to their own and their parents' anxiety levels and to their parents' (but not their own) depression. We conclude that child pupils are sensitive to individual differences in parents' pupils and emotional dispositions in community samples.

Pupillometry indexes ocular dominance plasticity.

Short-term monocular deprivation in normally sighted adult humans produces a transient shift of ocular dominance, boosting the deprived eye. This effect has been documented with both perceptual tests and through physiological recordings, but no previous study simultaneously measured physiological responses and the perceptual effects of deprivation. Here we propose an integrated experimental paradigm that combines binocular rivalry with pupillometry, to introduce an objective physiological index of ocular dominance plasticity, acquired concurrently with perceptual testing. Ten participants reported the perceptual dynamics of binocular rivalry, while we measured pupil diameter. Stimuli were a white and a black disk, each presented monocularly. Rivalry dynamics and pupil-size traces were compared before and after 2 h of monocular deprivation, achieved by applying a translucent patch over the dominant eye. Consistent with prior research, we observed that monocular deprivation boosts the deprived-eye signal and consequently increases ocular dominance. In line with previous studies, we also observed subtle but systematic modulations of pupil size that tracked alternations between exclusive dominance phases of the black or white disk. Following monocular deprivation, the amplitude of these pupil-size modulations increased, which is consistent with the post-deprivation boost of the deprived eye and the increase of ocular dominance. This provides evidence that deprivation impacts the effective strength of monocular visual stimuli, coherently affecting perceptual reports and the automatic and unconscious regulation of pupil diameter. Our results show that a combined paradigm of binocular rivalry and pupillometry gives new insights into the physiological mechanisms underlying deprivation effects.

Altered pupil light and darkness reflex and eye-blink responses in late-life depression.

BACKGROUND: Late-life depression (LLD) is a prevalent neuropsychiatric disorder in the older population. While LLD exhibits high mortality rates, depressive symptoms in older adults are often masked by physical health conditions. In younger adults, depression is associated with deficits in pupil light reflex and eye blink rate, suggesting the potential use of these responses as biomarkers for LLD. METHODS: We conducted a study using video-based eye-tracking to investigate pupil and blink responses in LLD patients (n = 25), older (OLD) healthy controls (n = 29), and younger (YOUNG) healthy controls (n = 25). The aim was to determine whether there were alterations in pupil and blink responses in LLD compared to both OLD and YOUNG groups. RESULTS: LLD patients displayed significantly higher blink rates and dampened pupil constriction responses compared to OLD and YOUNG controls. While tonic pupil size in YOUNG differed from that of OLD, LLD patients did not exhibit a significant difference compared to OLD and YOUNG controls. GDS-15 scores in older adults correlated with light and darkness reflex response variability and blink rates. PHQ-15 scores showed a correlation with blink rates, while MoCA scores correlated with tonic pupil sizes. CONCLUSIONS: The findings demonstrate that LLD patients display altered pupil and blink behavior compared to OLD and YOUNG controls. These altered responses correlated differently with the severity of depressive, somatic, and cognitive symptoms, indicating their potential as objective biomarkers for LLD.

Automated Pupillometry Is Able to Discriminate Patients with Acute Stroke from Healthy Subjects: An Observational, Cross-Sectional Study.

BACKGROUND: Automated pupillometry (AP) is a handheld, non-invasive tool that is able to assess pupillary light reflex dynamics and is useful for the detection of intracranial hypertension. Limited evidence is available on acute ischemic stroke (AIS) patients. The primary objective was to evaluate the ability of AP to discriminate AIS patients from healthy subjects (HS). Secondly, we aimed to compute a predictive score for AIS diagnosis based on clinical, demographic, and AP variables. METHODS: We included 200 consecutive patients admitted to a comprehensive stroke center who underwent AP assessment through NPi-200 (NeurOptics®) within 72 h of stroke onset and 200 HS. The mean values of AP parameters and the absolute differences between the AP parameters of the two eyes were considered in the analyses. Predictors of stroke diagnosis were identified through univariate and multivariate logistic regressions; we then computed a nomogram based on each variable's ß coefficient. Finally, we developed a web app capable of displaying the probability of stroke diagnosis based on the predictive algorithm. RESULTS: A high percentage of pupil constriction (CH, p < 0.001), a low constriction velocity (CV, p = 0.002), and high differences between these two parameters (p = 0.036 and p = 0.004, respectively) were independent predictors of AIS. The highest contribution in the predictive score was provided by CH, the Neurological Pupil Index, CV, and CV absolute difference, disclosing the important role of AP in the discrimination of stroke patients. CONCLUSIONS: The results of our study suggest that AP parameters, and in particular, those concerning pupillary constriction, may be useful for the early diagnosis of AIS.

Ocular working memory signals are flexible to behavioral priority and subjective imagery strength.

The pupillary light response was long considered a brainstem reflex, outside of cognitive influence. However, newer findings indicate that pupil dilation (and eye movements) can reflect content held "in mind" with working memory (WM). These findings may reshape understanding of ocular and WM mechanisms, but it is unclear whether the signals are artifactual or functional to WM. Here, we ask whether peripheral and oculomotor WM signals are sensitive to the task-relevance or "attentional state" of WM content. During eye-tracking, human participants saw both dark and bright WM stimuli, then were retroactively cued to the item that would most likely be tested. Critically, we manipulated the attentional priority among items by varying the cue reliability across blocks. We confirmed previous findings that remembering darker items is associated with larger pupils (vs. brighter), and that gaze is biased toward cued item locations. Moreover, we discovered that pupil and eye movement responses were influenced differently by WM item relevance. Feature-specific pupillary effects emerged only for highly prioritized WM items but were eliminated when cues were less reliable, and pupil effects also increased with self-reported visual imagery strength. Conversely, gaze position consistently veered toward the cued item location, regardless of cue reliability. However, biased microsaccades occurred at a higher frequency when cues were more reliable, though only during a limited post-cue time window. Therefore, peripheral sensorimotor processing is sensitive to the task-relevance or functional state of internal WM content, but pupillary and eye movement WM signals show distinct profiles. These results highlight a potential role for early visual processing in maintaining multiple WM content dimensions.NEW & NOTEWORTHY Here, we found that working memory (WM)-driven ocular inflections-feature-specific pupillary and saccadic biases-were muted for memory items that were less behaviorally relevant. This work illustrates that functionally informative goal signals may extend as early as the sensorimotor periphery, that pupil size may be under more fine-grained control than originally thought, and that ocular signals carry multiple dimensions of cognitively relevant information.

The resolution of proactive interference in a novel visual working memory task: A behavioral and pupillometric study.

Proactive interference (PI) occurs when previously learned information impairs memory for more recently learned information. Most PI studies have employed verbal stimuli, while the role of PI in visual working memory (VWM) has had relatively little attention. In the verbal domain, Johansson and colleagues (2018) found that pupil diameter - a real-time neurophysiological index of cognitive effort - reflects the accumulation and resolution of PI. Here we use a novel, naturalistic paradigm to test the behavioral and pupillary correlates of PI resolution for what-was-where item-location bindings in VWM. Importantly, in our paradigm, trials (PI vs. no-PI condition) are mixed in a block, and participants are naïve to the condition until they are tested. This design sidesteps concerns about differences in encoding strategies or generalized effort differences between conditions. Across three experiments (N = 122 total) we assessed PI's effect on VWM and whether PI resolution during memory retrieval is associated with greater cognitive effort (as indexed by the phasic, task-evoked pupil response). We found strong support for PI's detrimental effect on VWM (even with our spatially distributed stimuli), but no consistent link between interference resolution and effort during memory retrieval (this, even though the pupil was a reliable indicator that higher-performing individuals tried harder during memory encoding). We speculate that when explicit strategies are minimized, and PI resolution relies primarily on implicit processing, the effect may not be sufficient to trigger a robust pupillometric response.

Word frequency and cognitive effort in turns-at-talk: turn structure affects processing load in natural conversation.

Frequency distributions are known to widely affect psycholinguistic processes. The effects of word frequency in turns-at-talk, the nucleus of social action in conversation, have, by contrast, been largely neglected. This study probes into this gap by applying corpus-linguistic methods on the conversational component of the British National Corpus (BNC) and the Freiburg Multimodal Interaction Corpus (FreMIC). The latter includes continuous pupil size measures of participants of the recorded conversations, allowing for a systematic investigation of patterns in the contained speech and language on the one hand and their relation to concurrent processing costs they may incur in speakers and recipients on the other hand. We test a first hypothesis in this vein, analyzing whether word frequency distributions within turns-at-talk are correlated with interlocutors' processing effort during the production and reception of these turns. Turns are found to generally show a regular distribution pattern of word frequency, with highly frequent words in turn-initial positions, mid-range frequency words in turn-medial positions, and low-frequency words in turn-final positions. Speakers' pupil size is found to tend to increase during the course of a turn at talk, reaching a climax toward the turn end. Notably, the observed decrease in word frequency within turns is inversely correlated with the observed increase in pupil size in speakers, but not in recipients, with steeper decreases in word frequency going along with steeper increases in pupil size in speakers. We discuss the implications of these findings for theories of speech processing, turn structure, and information packaging. Crucially, we propose that the intensification of processing effort in speakers during a turn at talk is owed to an informational climax, which entails a progression from high-frequency, low-information words through intermediate levels to low-frequency, high-information words. At least in English conversation, interlocutors seem to make use of this pattern as one way to achieve efficiency in conversational interaction, creating a regularly recurring distribution of processing load across speaking turns, which aids smooth turn transitions, content prediction, and effective information transfer.

Investigation of the behavior of tinnitus patients under varying listening conditions with simultaneous electroencephalography and pupillometry.

OBJECTIVE: This study aims to control all hearing thresholds, including extended high frequencies (EHFs), presents stimuli of varying difficulty levels, and measures electroencephalography (EEG) and pupillometry responses to determine whether listening difficulty in tinnitus patients is effort or fatigue-related. METHODS: Twenty-one chronic tinnitus patients and 26 matched healthy controls having normal pure-tone averages with symmetrical hearing thresholds were included. Subjects were evaluated with 0.125-20 kHz pure-tone audiometry, Montreal Cognitive Assessment Test (MoCA), Tinnitus Handicap Inventory (THI), EEG, and pupillometry. RESULTS: Pupil dilatation and EEG alpha power during the "encoding" phase of the presented sentence in tinnitus patients were less in all listening conditions (p < .05). Also, there was no statistically significant relationship between EEG and pupillometry components for all listening conditions and THI or MoCA (p > .05). CONCLUSION: EEG and pupillometry results under various listening conditions indicate potential listening effort in tinnitus patients even if all frequencies, including EHFs, are controlled. Also, we suggest that pupillometry should be interpreted with caution in autonomic nervous system-related conditions such as tinnitus.

The role of retinal irradiance estimates in melanopsin-driven retinal responsivity: A reanalysis of the post-illumination pupil response (PIPR) in seasonal affective disorder.

To isolate melanopsin contributions to retinal sensitivity measured by the post-illumination pupil response (PIPR), controlling for individual differences in non-melanopsin contributions including retinal irradiance is required. When methodologies to negate such differences present barriers, statistical controls have included age, baseline diameter, iris pigmentation, and circadian time of testing. Alternatively, the pupil light reflex (PLR) and calculations estimating retinal irradiance both reflect retinal irradiance, while the PLR also reflects downstream pathways. We reanalyzed data from an observational, correlational study comparing the PIPR across seasons in seasonal affective disorder (SAD) and controls. The PIPR was measured in 47 adults in Pittsburgh, Pennsylvania (25 SAD) over 50 s after 1 s red and blue stimuli of 15.3 log photons/cm2/s. The PLR was within 1 s while PIPR was averaged over 10-40 seconds post-stimulus. Two raters ranked iris pigmentation using a published scale. We evaluated model fit using Akaike's Information Criterion (AIC) across different covariate sets. The best fitting models included either estimated retinal irradiance or PLR, and circadian time of testing. The PLR is collected contemporaneously in PIPR studies and is an individually specific measure of nonspecific effects, while being minimally burdensome. This work extends the prior publication by introducing theoretically grounded covariates that improved analytic model fits based on AIC specific to the present methods and sample. Such quantitative methods could be helpful in studies which must balance participant and researcher burden against tighter methodological controls of individual differences in retinal irradiance.

Mydriasis in eastern box turtles (Terrapene carolina carolina) following topical administration of proparacaine, 10% phenylephrine, and rocuronium bromide.

OBJECTIVE: To determine the mydriatic effect of topical 10% phenylephrine with 10 mg/mL rocuronium bromide and compare this protocol with and without pretreatment with proparacaine. ANIMALS STUDIED: Ten client-owned pet adult eastern box turtles (Terrapene carolina carolina). PROCEDURES: All turtles were sedated with 8 mg/kg alfaxalone intramuscularly. One group of four turtles received four 20 µL drops of 10% phenylephrine and four 20 µL drops of rocuronium bromide in the right eye. Another group of four turtles received one standard drop of proparacaine followed by four 20 µL drops of 10% phenylephrine and four 20 µL drops of rocuronium bromide in the right eye. Two control group turtles received four 20 µL drops of saline in the right eye. The left eye was untreated in all turtles. Drops of the same type were separated by 2 min while drops of different types were separated by 5 min. Pupil size was recorded at 0, 15, 30, 60, 90, 120, 180, 240, and 360 min after administration of the final drop. RESULTS: Treatment with 10% phenylephrine and rocuronium bromide resulted in pupil diameter changes from baseline that were statistically significant from zero at 60, 90, and 120 min in the non-proparacaine group and 90 min in the proparacaine group. The time to peak effect was 90 min in the proparacaine group and 75 min in the non-proparacaine group. Saline-treated pupils in the control group decreased in diameter over the study period. Overall, the treated eyes of the proparacaine group and non-proparacaine group were not different from each other, but both dilated more than the control group. CONCLUSIONS: Rocuronium bromide and 10% phenylephrine can produce effective and safe mydriasis in eastern box turtles, but there was wide interindividual variation in effectiveness. Proparacaine did not improve the mydriatic effect.

Utility of Automated Infrared Pupillometry in Assessing the Prolonged Course of Organophosphate Poisoning: A Case Report.

Central and autonomic nervous system signs of organophosphate poisoning (OP), such as altered consciousness, noticeable lacrimation, and salivation, can be influenced by medications used in intensive care settings, such as atropine and pralidoxime methyl (PAM). Because of this, there are no established methods for assessing the duration of OP while receiving antidotal treatment. In the present case, we used the Neurological Pupil Index (NPi) to evaluate the duration of OP in an 82-year-old woman who attempted suicide by ingesting up to 100 mL of fenitrothion. Until hospitalization day (HD) 20, discontinuation of atropine led to the recurrence of altered consciousness, while its reinstatement resulted in improvement; this made it difficult to assess the prolongation of OP based on signs and symptoms. Until HD 20, the NPi remained at 0/0, and subsequently, it increased. Additionally, even after discontinuing atropine, consciousness, tearing, and salivation did not worsen, indicating recovery from OP. On HD 26, serum acetylcholinesterase (AChE) levels were elevated above the measurable level for the first time, following an increase in the NPi. In this case, assessing the persistence of OP based on signs was challenging because these signs improved with atropine and PAM treatment. The improvement in NPi levels coincided with an improvement in poisoning, suggesting that NPi is useful for evaluating the duration of OP. NPi is noninvasive and sensitive compared to AChE, which is used to gauge the persistence of OP and could be used to allow earlier cessation of medication and guide appropriate treatment durations.

An examination of individual differences in levels of processing.

The present study examined individual differences in levels of processing. Participants completed a cued recall task in which they made either rhyme or semantic judgements on pairs of items. Pupillary responses during encoding were recorded as a measure of the allocation of attentional effort and participants completed multiple measures of working and long-term memory. The results suggested levels of processing effect in both accuracy and pupillary responses with deeper levels of processing demonstrating higher accuracy and larger pupillary responses than shallower levels of processing. Most participants demonstrated levels of processing effect, but there was substantial variability in the size of the effect. Variation in levels of processing was positively related to individual differences in long-term memory and the magnitude of the pupillary levels of processing effect, but not working memory. These results suggest that some of the variation in levels of processing is likely due to individual differences in the allocation of attentional effort (particularly to items processed deeply) during encoding.

Cognitive load in tele-robotic surgery: a comparison of eye tracker designs.

PURPOSE: Eye gaze tracking and pupillometry are evolving areas within the field of tele-robotic surgery, particularly in the context of estimating cognitive load (CL). However, this is a recent field, and current solutions for gaze and pupil tracking in robotic surgery require assessment. Considering the necessity of stable pupillometry signals for reliable cognitive load estimation, we compare the accuracy of three eye trackers, including head and console-mounted designs. METHODS: We conducted a user study with the da Vinci Research Kit (dVRK), to compare the three designs. We collected eye tracking and dVRK video data while participants observed nine markers distributed over the dVRK screen. We compute and analyze pupil detection stability and gaze prediction accuracy for the three designs. RESULTS: Head-worn devices present better stability and accuracy of gaze prediction and pupil detection compared to console-mounted systems. Tracking stability along the field of view varies between trackers, with gaze predictions detected at invalid zones of the image with high confidence. CONCLUSION: While head-worn solutions show benefits in confidence and stability, our results demonstrate the need to improve eye tacker performance regarding pupil detection, stability, and gaze accuracy in tele-robotic scenarios.

Pupil dilation reflects effortful action invigoration in overcoming aversive Pavlovian biases.

"Pavlovian" or "motivational" biases describe the phenomenon that the valence of prospective outcomes modulates action invigoration: Reward prospect invigorates action, whereas punishment prospect suppresses it. The adaptive role of these biases in decision-making is still unclear. One idea is that they constitute a fast-and-frugal decision strategy in situations characterized by high arousal, e.g., in presence of a predator, which demand a quick response. In this pre-registered study (N = 35), we tested whether such a situation-induced via subliminally presented angry versus neutral faces-leads to increased reliance on Pavlovian biases. We measured trial-by-trial arousal by tracking pupil diameter while participants performed an orthogonalized Motivational Go/NoGo Task. Pavlovian biases were present in responses, reaction times, and even gaze, with lower gaze dispersion under aversive cues reflecting "freezing of gaze." The subliminally presented faces did not affect responses, reaction times, or pupil diameter, suggesting that the arousal manipulation was ineffective. However, pupil dilations reflected facets of bias suppression, specifically the physical (but not cognitive) effort needed to overcome aversive inhibition: Particularly strong and sustained dilations occurred when participants managed to perform Go responses to aversive cues. Conversely, no such dilations occurred when they managed to inhibit responses to Win cues. These results suggest that pupil diameter does not reflect response conflict per se nor the inhibition of prepotent responses, but specifically effortful action invigoration as needed to overcome aversive inhibition. We discuss our results in the context of the "value of work" theory of striatal dopamine.

Listening handicap in tinnitus patients with normal extended high frequencies from the perspective of the autonomic nervous system-Effort or fatigue?

OBJECTIVE: In previous studies, the results regarding the presence of listening effort or fatigue in tinnitus patients were inconsistent. The reason for this inconsistency could be that extended high frequencies, which can cause listening handicap, were not within normal limits. Therefore, this study aimed to evaluate the listening skills in tinnitus patients by matching the normal hearing thresholds at all frequencies, including the extended high frequency. METHODS: Eighteen chronic tinnitus patients and thirty matched healthy controls having normal pure-tone average with symmetrical hearing thresholds was included. Subjects were evaluated with 0.125-20 kHz pure-tone audiometry, Montreal cognitive assessment test (MoCA), Tinnitus Handicap Inventory (THI), Matrix Test, Pupillometry. RESULTS: Pupil dilatation in the 'coding' phase of the sentence presented in tinnitus patients was less than in the control group (p < 0.05). There was no difference between the groups for Matrix test scores (p > 0.05) Also, there was no statistically significant correlation between THI and Pupillometry components nor between MoCA (p > 0.05). CONCLUSION: Even though tinnitus patients had normal hearing in the range of 0.125-20 kHz, their autonomic nervous system responses during listening differed from healthy subjects. This difference was interpreted for potential listening fatigue in tinnitus patients.