"Looking at nothing": An implicit ocular motor index of face recognition in developmental prosopagnosia.

Subjects often look towards to previous location of a stimulus related to a task even when that stimulus is no longer visible. In this study we asked whether this effect would be preserved or reduced in subjects with developmental prosopagnosia. Participants learned faces presented in video-clips and then saw a brief montage of four faces, which was replaced by a screen with empty boxes, at which time they indicated whether the learned face had been present in the montage. Control subjects were more likely to look at the blank location where the learned face had appeared, on both hit and miss trials, though the effect was larger on hit trials. Prosopagnosic subjects showed a reduced effect, though still better on hit than on miss trials. We conclude that explicit accuracy and our implicit looking at nothing effect are parallel effects reflecting the strength of the neural activity underlying face recognition.

Visual imagery deficits in posterior cortical atrophy.

Visual imagery has a close overlapping relationship with visual perception. Posterior cortical atrophy (PCA) is a neurodegenerative syndrome marked by early impairments in visuospatial processing and visual object recognition. We asked whether PCA would therefore also be marked by deficits in visual imagery, tested using objective forced-choice questionnaires, and whether imagery deficits would be selective for certain properties. We recruited four patients with PCA and a patient with integrative visual agnosia due to bilateral occipitotemporal strokes for comparison. We administered a test battery probing imagery for object shape, size, colour lightness, hue, upper-case letters, lower-case letters, word shape, letter construction, and faces. All subjects showed significant impairments in visual imagery, with imagery for lower-case letters most likely to be spared. We conclude that PCA subjects can show severe deficits in visual imagery. Further work is needed to establish how frequently this occurs and how early it can be found.

Faces, English words and Chinese characters: a study of dual-task interference in mono-and bilingual speakers.

The many-to-many hypothesis suggests that face and visual-word processing tasks share neural resources in the brain, even though they show opposing hemispheric asymmetries in neuroimaging and neuropsychologic studies. Recently it has been suggested that both stimulus and task effects need to be incorporated into the hypothesis. A recent study found dual-task interference between face and text functions that lateralized to the same hemisphere, but not when they lateralized to different hemispheres. However, it is not clear whether a lack of interference between word and face recognition would occur for other languages, particularly those with a morpho-syllabic script, like Chinese, for which there is some evidence of greater right hemispheric involvement. Here, we used the same technique to probe for dual-task interference between English text, Chinese characters and face recognition. We tested 20 subjects monolingual for English and 20 subjects bilingual for Chinese and English. We replicated the prior result for English text and showed similar results for Chinese text with no evidence of interference with faces. We also did not find interference between Chinese and English text. The results support a view in which reading English words, reading Chinese characters and face identification have minimal sharing of neural resources.

The impact of simulated hemianopia on visual search for faces, words, and cars.

Tests of visual search can index the effects of perceptual load and compare the processing efficiency for different object types, particularly when one examines the set-size effect, the increase in search time for each additional stimulus in an array. Previous studies have shown that the set-size effect is increased by manoeuvres that impede object processing, and in patients with object processing impairments. In this study, we examine how the low-level visual impairment of hemianopia affects visual search for complex objects, using a virtual paradigm. Forty-two healthy subjects performed visual search for faces, words, or cars with full-viewing as well as gaze-contingent simulations of complete left or right hemianopia. Simulated hemianopia lowered accuracy and discriminative power and increased response times and set-size effects, similarly for faces, words and cars. A comparison of set-size effects between target absent and target present trials did not show a difference between full-view and simulated hemianopic conditions, and a model of decision-making suggested that simulated hemianopia reduced the rate of accumulation of perceptual data, but did not change decision thresholds. We conclude that simulated hemianopia reduces the efficiency of visual search for complex objects, and that such impairment should be considered when interpreting results from high-level object processing deficits.

Oblique saccades in internuclear ophthalmoplegia.

PURPOSE: Oblique saccades often display component stretching, in which the shorter vector in one cardinal direction is slowed so that its duration matches that of the longer vector in the orthogonal direction, resulting in a straighter trajectory. In internuclear ophthalmoplegia, adducting saccades are typically slowed while vertical saccades are unaffected. It is not known whether these slowed adducting movements are accompanied by adaptive component stretching of the vertical vector during oblique saccades. This was a cross-sectional study. We recorded the saccadic eye movement in 5 patients with right or bilateral internuclear ophthalmoplegia from multiple sclerosis and 17 healthy controls, using an EyeLink 1000 machine. The target stimulus was located at varying angles (0-360) and amplitudes (4, 8, 12 degrees). For each saccade we have calculated the curvature index as the main outcome measure, which is the area between the actual and ideal straight trajectory for oblique saccadic eye movements, divided by the square of the length of the straight trajectory, to give a unit-less metric for curvature. In the 17 control subjects, curvature showed a strong positive correlation between adducting saccades and the yoked abducting saccades of the other eye. In internuclear ophthalmoplegia, adducting saccades showed a strong curvature concave to the horizontal meridian, indicating inadequate component stretching, while abducting saccades did not differ from controls. This new sign of oblique saccadic curvature in internuclear ophthalmoplegia indicates a limitation of the range of central adaptive changes in response to distal lesions affecting transmission of the saccadic command.

The inversion effect in word recognition: The effect of language familiarity and handwriting.

Humans have expertise with visual words and faces. One marker of this expertise is the inversion effect. This is attributed to experience with those objects being biased towards a canonical orientation, rather than some inherent property of object structure or perceptual anisotropy. To confirm the role of experience, we measured inversion effects in word matching for familiar and unfamiliar languages. Second, we examined whether there may be more demands on reading expertise with handwritten stimuli rather than computer font, given the greater variability and irregularities in the former, with the prediction of larger inversion effects for handwriting. We recruited two cohorts of subjects, one fluent in Farsi and the other in Punjabi, neither of whom were able to read the other's language. Subjects performed a match-to-sample task with words in either computer fonts or handwritings. Subjects were more accurate and faster with their familiar language, even when it was inverted. Inversion effects were present for the familiar but not the unfamiliar language. The inversion effect in accuracy for handwriting was larger than that for computer fonts in the familiar language. We conclude that the word inversion effect is generated solely by orientation-biased experience, and that demands on this expertise are greater with handwriting than computer font.

Contrasting domain-general and domain-specific accounts in cognitive neuropsychology: An outline of a new approach with developmental prosopagnosia as a case.

The backbone of cognitive neuropsychology is the observation of (double) dissociations in performance between patients, suggesting some degree of independence between cognitive processes (domain specificity). In comparison, observations of associations between disorders/deficits have been deemed less evidential in neuropsychological theorizing about cognitive architecture. The reason is that associations can reflect damage to independent cognitive processes that happen to be mediated by structures commonly affected by the same brain disorder rather than damage to a shared (domain-general) mechanism. Here we demonstrate that it is in principle possible to discriminate between these alternatives by means of a procedure involving large unbiased samples. We exemplify the procedure in the context of developmental prosopagnosia (DP), but the procedure is in principle applicable to all neuropsychological deficits/disorders. A simulation of the procedure on a dataset yields estimates of dissociations/associations that are well in line with existing DP-studies, and also suggests that seemingly selective disorders can reflect damage to both domain-general and domain-specific cognitive processes. However, the simulation also highlights some limitations that should be considered if the procedure is to be applied prospectively. The main advantage of the procedure is that allows for examination of both associations and dissociations in the same sample. Hence, it may help even the balance in the use of associations and dissociations as grounds for neuropsychological theorizing.

Whole-object effects in visual word processing: Parallels with and differences from face recognition.

Visual words and faces differ in their structural properties, but both are objects of high expertise. Holistic processing is said to characterize expert face recognition, but the extent to which whole-word processes contribute to word recognition is unclear, particularly as word recognition is thought to proceed by a component-based process. We review the evidence for experimental effects in word recognition that parallel those used to support holistic face processing, namely inversion effects, the part-whole task, and composite effects, as well as the status of whole-word processing in pure alexia and developmental dyslexia, contrasts between familiar and unfamiliar languages, and the differences between handwriting and typeset font. The observations support some parallels in whole-object influences between face and visual word recognition, but do not necessarily imply similar expert mechanisms. It remains to be determined whether and how the relative balance between part-based and whole-object processing differs for visual words and faces.

Search for Face Identity or Expression: Set Size Effects in Developmental Prosopagnosia.

The set size effect during visual search indexes the effects of processing load and thus the efficiency of perceptual mechanisms. Our goal was to investigate whether individuals with developmental prosopagnosia show increased set size effects when searching faces for face identity and how this compares to search for face expression. We tested 29 healthy individuals and 13 individuals with developmental prosopagnosia. Participants were shown sets of three to seven faces to judge whether the identities or expressions of the faces were the same across all stimuli or if one differed. The set size effect was the slope of the linear regression between the number of faces in the array and the response time. Accuracy was similar in both controls and prosopagnosic participants. Developmental prosopagnosic participants displayed increased set size effects in face identity search but not in expression search. Single-participant analyses reveal that 11 developmental prosopagnosic participants showed a putative classical dissociation, with impairments in identity but not expression search. Signal detection theory analysis showed that identity set size effects were highly reliable in discriminating prosopagnosic participants from controls. Finally, the set size ratios of same to different trials were consistent with the predictions of self-terminated serial search models for control participants and prosopagnosic participants engaged in expression search but deviated from those predictions for identity search by the prosopagnosic cohort. We conclude that the face set size effect reveals a highly prevalent and selective perceptual inefficiency for processing face identity in developmental prosopagnosia.

Object recognition in acquired and developmental prosopagnosia.

Whether face and object recognition are dissociated in prosopagnosia continues to be debated: a recent review highlighted deficiencies in prior studies regarding the evidence for such a dissociation. Our goal was to study cohorts with acquired and developmental prosopagnosia with a complementary battery of tests of object recognition that address prior limitations, as well as evaluating for residual effects of object expertise. We studied 15 subjects with acquired and 12 subjects with developmental prosopagnosia on three tests: the Old/New Tests, the Cambridge Bicycle Memory Test, and the Expertise-adjusted Test of Car Recognition. Most subjects with developmental prosopagnosia were normal on the Old/New Tests: for acquired prosopagnosia, subjects with occipitotemporal lesions often showed impairments while those with anterior temporal lesions did not. Ten subjects showed a putative classical dissociation between the Cambridge Face and Bicycle Memory Tests, seven of whom had normal reaction times. Both developmental and acquired groups showed reduced car recognition on the expertise-adjusted test, though residual effects of expertise were still evident. Two subjects with developmental prosopagnosia met criteria for normal object recognition across all tests. We conclude that strong evidence for intact object recognition can be found in a few subjects but the majority show deficits, particularly those with the acquired form. Both acquired and developmental forms show residual but reduced object expertise effects.

Self-face and self-body advantages in congenital prosopagnosia: evidence for a common mechanism.

Prosopagnosia is a disorder leading to difficulties in recognizing faces. However, recent evidence suggests that individuals with congenital prosopagnosia can achieve considerable accuracy when they have to recognize their own faces (self-face advantage). Yet, whether this advantage is face-specific or not is still unclear. Here, we aimed to investigate whether individuals with congenial prosopagnosia show a self-advantage also in recognizing other self body-parts and, if so, whether the advantage for the body parts differs from the one characterizing the self-face. Eight individuals with congenital prosopagnosia and 22 controls underwent a delayed matching task in which they were required to recognize faces, hands and feet belonging to the self or to others. Controls showed a similar self-advantage for all the stimuli tested; by contrast, individuals with congenital prosopagnosia showed a larger self-advantage with faces compared to hands and feet, mainly driven by their deficit with others' faces. In both groups the self-advantages for the different body parts were strongly and significantly correlated. Our data suggest that the self-face advantage showed by individuals with congenital prosopagnosia is not face-specific and that the same mechanism could be responsible for both the self-face and self body-part advantages.

Diagnosing Prosopagnosia: The Utility of Visual Noise in the Cambridge Face Recognition Test.

Adding visual noise to facial images has been used to increase reliance on configural processing. Whether this enhances the ability of tests to diagnose prosopagnosia is not known. We examined 15 subjects with developmental prosopagnosia, 13 subjects with acquired prosopagnosia, and 38 control subjects with the Cambridge Face Memory Test. We compared their performance on the second phase, without visual noise, and on the third phase, which adds visual noise. We analyzed the results with signal detection theory methods. The performance of controls worsened more than did that of prosopagnosic subjects when noise was added. The second phase showed better ability to discriminate between prosopagnosic and control subjects than did the third phase. For developmental prosopagnosia, a test using only the 48 trials of the first and second phases yielded sensitivity of 88% and specificity of 91% with a criterion of 33/48 correct, performance characteristics that are similar for a criterion of 43/72 for the whole test. We conclude that a shortened Cambridge Face Memory Test without the noisy images may be a quicker yet equally effective instrument for diagnosing prosopagnosia. The theoretical advantage of noisy images is outweighed by the poorer performance of control subjects with visual noise.

Focusing and orienting spatial attention differently modulate crowding in central and peripheral vision.

The allocation of attentional resources to a particular location or object in space involves two distinct processes: an orienting process and a focusing process. Indeed, it has been demonstrated that performance of different visual tasks can be improved when a cue, such as a dot, anticipates the position of the target (orienting), or when its dimensions (as in the case of a small square) inform about the size of the attentional window (focusing). Here, we examine the role of these two components of visuo-spatial attention (orienting and focusing) in modulating crowding in peripheral (Experiment 1 and Experiment 3a) and foveal (Experiment 2 and Experiment 3b) vision. The task required to discriminate the orientation of a target letter "T," close to acuity threshold, presented with left and right "H" flankers, as a function of target-flanker distance. Three cue types have been used: a red dot, a small square, and a big square. In peripheral vision (Experiment 1 and Experiment 3a), we found a significant improvement with the red dot and no advantage when a small square was used as a cue. In central vision (Experiment 2 and Experiment 3b), only the small square significantly improved participants' performance, reducing the critical distance needed to recover target identification. Taken together, the results indicate a behavioral dissociation of orienting and focusing attention in their capability of modulating crowding. In particular, we confirmed that orientation of attention can modulate crowding in visual periphery, while we found that focal attention can modulate foveal crowding.

Italian normative data and validation of two neuropsychological tests of face recognition: Benton Facial Recognition Test and Cambridge Face Memory Test.

The Benton Facial Recognition Test (BFRT) and Cambridge Face Memory Test (CFMT) are two of the most common tests used to assess face discrimination and recognition abilities and to identify individuals with prosopagnosia. However, recent studies highlighted that participant-stimulus match ethnicity, as much as gender, has to be taken into account in interpreting results from these tests. Here, in order to obtain more appropriate normative data for an Italian sample, the CFMT and BFRT were administered to a large cohort of young adults. We found that scores from the BFRT are not affected by participants' gender and are only slightly affected by participant-stimulus ethnicity match, whereas both these factors seem to influence the scores of the CFMT. Moreover, the inclusion of a sample of individuals with suspected face recognition impairment allowed us to show that the use of more appropriate normative data can increase the BFRT efficacy in identifying individuals with face discrimination impairments; by contrast, the efficacy of the CFMT in classifying individuals with a face recognition deficit was confirmed. Finally, our data show that the lack of inversion effect (the difference between the total score of the upright and inverted versions of the CFMT) could be used as further index to assess congenital prosopagnosia. Overall, our results confirm the importance of having norms derived from controls with a similar experience of faces as the "potential" prosopagnosic individuals when assessing face recognition abilities.

Right perceptual bias and self-face recognition in individuals with congenital prosopagnosia.

The existence of a drift to base judgments more on the right half-part of facial stimuli, which falls in the observer's left visual field (left perceptual bias (LPB)), in normal individuals has been demonstrated. However, less is known about the existence of this phenomenon in people affected by face impairment from birth, namely congenital prosopagnosics. In the current study, we aimed to investigate the presence of the LPB under face impairment conditions using chimeric stimuli and the most familiar face of all: the self-face. For this purpose we tested 10 participants with congenital prosopagnosia and 21 healthy controls with a face matching task using facial stimuli, involving a spatial manipulation of the left and the right hemi-faces of self-photos and photos of others. Even though congenital prosopagnosics performance was significantly lower than that of controls, both groups showed a consistent self-face advantage. Moreover, congenital prosopagnosics showed optimal performance when the right side of their face was presented, that is, right perceptual bias, suggesting a differential strategy for self-recognition in those subjects. A possible explanation for this result is discussed.

Management of possible stroke by laypeople in pre-hospital setting: who should we train?

BACKGROUND AND AIM: The pre-hospital management of a possible stroke is fundamental for the transport of patients to the correct HUB facility; thus, they must be transported to the Emergency Department (ED) by EMS vehicles. Our study aims to analyze the factors correlated with a higher probability of accessing the ED through the EMS in this event. METHODS: This is a retrospective observational study. All accesses in the 120 EDs of the Lombardy region, with a diagnosis of discharge whose symptoms could resemble CPSS, were analyzed between 1 January 2019 and 31 December 2019. RESULTS: We identified an increased probability of using the EMS vehicles of 0,05% (I.C. 95%: 0.04% - 0.06%; p<0.0001) for each additional year of age, considering patients aged 20 to 100 years and the percentage was significantly higher in the female population (58% vs 49%; p<0.001). Moreover, we calculated that the incidence of stroke was approximately 140 cases per 100,000 inhabitants. CONCLUSIONS: Only half of the citizens in the Lombardy region use the EMS in case of suspicion of stroke; further information campaigns are essential to educate citizens. Information strategies should be directed especially at men between 30 and 59 years old.

Emergency Department waiting-time in the post pandemic era: new organizational models, a challenge for the future.

BACKGROUND AND AIM: Covid-19 has profoundly changed the Emergency Department system in Lombardy, especially for the type of accesses and the number of diagnoses. Accordingly, the pre-hospital rescue system has undergone heavy changes, in particular regarding the times of rescue. Despite this, studies concerning the post-pandemic phase are lacking to understand whether the conditions of the emergency systems has resumed to the pre-pandemic period. The aim of the study is to evaluate the length of stay (LOS) phenomenon in the emergency departments (EDs) in the post-pandemic era. METHODS: a retrospective observational study was conducted, which analyzed the first six months of the years 2019, 2021 and 2022. The pandemic peak phase, corresponding to the first months of 2020, wasn't included. The investigated area included the provinces of Milan and Monza, a metropolitan area with 4 million inhabitants. RESULTS: The average time spent by patients in the ED increased by +3.8 hours in 2022 and by +1.3 hours in 2021 compared to 2019. The average time from ED access to hospitalization also increased by +4.8 hours in 2022 and +5.0 hours in 2021 compared to 2019. The percentage of time in ED recorded in a National Emergency Department Overcrowding Study (NEDOCS) in black code in 2022 reached 5.4% against 1.7% in 2021 and 0.5 % in 2019. CONCLUSIONS: data show an increase in the time spent in the EDs and an increase in the overcrowding, according to the NEDOCS index. New management models and a reorganization of EDs are needed as the workload has increased significantly.

The persistence of remote visual semantic memory following ocular blindness.

Subjects with complete ocular blindness in both eyes provide a unique opportunity to study the long-term durability of visual semantic memory. In this cross-sectional study we recruited eleven subjects who had acquired blindness for between 1 and 36 years. For comparison, we studied four subjects with congenital blindness and seventeen age- and sex-matched sighted control subjects. We administered ten forced-choice questionnaires that probed one auditory category and four visual categories, namely object shape and size; object hue and lightness; word and letter shape; and the shape and features of famous faces. Subjects with congenital blindness performed worse than controls on all visual categories, but nevertheless performed better than chance on object structure or colour, suggesting that the answers to some questions about visual properties can be derived from haptic or non-visual semantic information. Subjects with acquired blindness performed similarly to controls on all categories except for facial memory, particularly for facial features. We conclude that there is a substantial "permastore" of visual semantic memory but that facial memories are less durable, perhaps indicating that they are either less over-learned or more dependent on visual representations than other forms of visual object information.

An ocular motor index of rapid face recognition: The 'looking-at-nothing' effect.

In the looking at nothing effect, subjects performing a task involving stimuli that are no longer visible tend to fixate the regions on an empty screen where those stimuli had been located. We performed three experiments to examine whether this effect could serve as an index of short-term face recognition. Subjects saw a short video of a person's face and then saw briefly a choice screen of four faces, followed by a screen with empty boxes, after which they responded whether the learned face was one of the four. Fixations made while the screen without faces was present were more likely to be directed towards the target face when it had been shown, and this was the case not only on hit trails, but also on miss trials. Examining fixations made during a 3-second window showed that this looking at nothing effect was present for the first fixation only, after which subjects were more likely to fixate the other empty boxes, a 'looking away from nothing' effect. Including data from all three experiments showed an age-related decline in discriminative sensitivity but not in the looking at nothing effect. However, there was a positive correlation between discriminative sensitivity and the looking at nothing effect. We conclude that the looking at nothing effect can index rapid face recognition, that it is related to explicit discriminative performance, and that its short-term dynamics bear similarities to inhibition of return.

Facial identity and facial speech processing in developmental prosopagnosia.

The neural substrate of acquired prosopagnosia, including its lateralization, remains a matter of investigation. Face processing networks in healthy subjects are right dominant, and acquired prosopagnosia usually results from right or bilateral lesions. Nevertheless, there may be a complementary contribution of the left hemisphere to certain types of face processing. Prior reports suggest that this might be processing faces depicted by line contours, or lip reading. We performed two behavioural studies in seven subjects with developmental prosopagnosia. The first examined their ability to match faces across viewpoint changes, with either unaltered photographs or images that had been reduced to line elements. Prosopagnosic subjects had normal performance with line-contour faces, but failed to show the normal benefit from the additional information in unaltered photographs. The second experiment examined their ability to perceive facial speech patterns. Prosopagnosic subjects could detect, discriminate and identify facial speech patterns, but most showed reduced use of these cues or anomalous audiovisual integration in the McGurk effect, with only one subject performing normally. We conclude that developmental prosopagnosia can be associated with a subtle impairment in lip reading, which in prior studies of acquired lesions has been associated more with left than with right fusiform damage.