What is the prevalence of developmental prosopagnosia? An empirical assessment of different diagnostic cutoffs.

The prevalence of developmental prosopagnosia (DP), lifelong face recognition deficits, is widely reported to be 2-2.5%. However, DP has been diagnosed in different ways across studies, resulting in differing prevalence rates. In the current investigation, we estimated the range of DP prevalence by administering well-validated objective and subjective face recognition measures to an unselected web-based sample of 3116 18-55 year-olds and applying DP diagnostic cutoffs from the last 14 years. We found estimated prevalence rates ranged from .64-5.42% when using a z-score approach and .13-2.95% when using a percentile approach, with the most commonly used cutoffs by researchers having a prevalence rate of .93% (z-score, .45% when using percentiles). We next used multiple cluster analyses to examine whether there was a natural grouping of poorer face recognizers but failed to find consistent grouping beyond those with generally above versus below average face recognition. Lastly, we investigated whether DP studies with more relaxed diagnostic cutoffs were associated with better performance on the Cambridge Face Perception Test. In a sample of 43 studies, there was a weak nonsignificant association between greater diagnostic strictness and better DP face perception accuracy (Kendall's tau-b correlation, τb =.18 z-score; τb = .11 percentiles). Together, these results suggest that researchers have used more conservative DP diagnostic cutoffs than the widely reported 2-2.5% prevalence. We discuss the strengths and weaknesses of using more inclusive cutoffs, such as identifying mild and major forms of DP based on DSM-5.

"This looks like a movie": a case report of post-surgical amnesia.

A 52-year-old male patient with a background of adaptive personality disorder was admitted for mitral valve repair and cardiac ablation for atrial fibrillation. He suffered intraoperative complications with severe mitral insufficiency that suffered ischemia.. Post-operatively, he demonstrated acute loss of retrograde autobiographical memory, prosopagnosia and a loss of public semantic memory. His CT scan was normal and MRI was not possible due to intra-cardiac leads. An initial diagnosis of hypoxic-ischemic encephalopathy was considered. A neuropsychological examination undertaken 20 days after his surgery showed a severe alteration of retrograde autobiographical memory, marked alteration of semantic knowledge and prosopagnosia. He demonstrated an average performance in tasks measuring constructional praxis, visuospatial ability, and executive functions. 34 days after surgery, and after a short nap, the patient "returns" to the day before admission and consequently recovers his memory. Repeat neuropsychological assessment demonstrated performance within the normal range across all previously tested domains. This sudden recovery of memory, together with a normal MRI, led to a rethinking of the diagnosis of dissociative amnesia. This case illustrates the long-standing discussion about the organic or functional origin of some memory disorders, in which, despite advances in neuroimaging techniques, it is still difficult to know their etiology .

Multiple-stage impairments of unfamiliar face learning in developmental prosopagnosia: Evidence from fMRI repetition suppression and multi-voxel pattern stability.

Individuals with developmental prosopagnosia (DP) are characterized by severe face recognition deficits, yet it remains unknown how they are hindered in the process of unfamiliar face learning. Here we tracked the changes of neural activation during unfamiliar face repetition in DP with fMRI to reveal their neural deficits in learning unfamiliar faces. At the perceptual level, we found that the bilateral fusiform face area (FFA) in individuals with DP showed attenuated repetition suppression for faces, suggesting an inefficient perceptual analysis for learned faces. At the mnemonic level, individuals with DP showed decreased multi-voxel pattern stability for repeated faces in bilateral medial temporal lobe (MTL), suggesting an unstable mnemonic representation for learned faces. In addition, resting-state functional connectivity between the FFA and MTL was also disrupted in individuals with DP. Finally, the MTL's unstable mnemonic representation was associated with the impaired face recognition performance in DP. In sum, our study provides evidence that individuals with DP showed multi-stage neural deficits in unfamiliar face learning and sheds new light on how unfamiliar faces are learned in normal population.

Normal colour perception in developmental prosopagnosia.

Developmental prosopagnosia (DP) is a selective neurodevelopmental condition defined by lifelong impairments in face recognition. Despite much research, the extent to which DP is associated with broader visual deficits beyond face processing is unclear. Here we investigate whether DP is accompanied by deficits in colour perception. We tested a large sample of 92 DP individuals and 92 sex/age-matched controls using the well-validated Ishihara and Farnsworth-Munsell 100-Hue tests to assess red-green colour deficiencies and hue discrimination abilities. Group-level analyses show comparable performance between DP and control individuals across both tests, and single-case analyses indicate that the prevalence of colour deficits is low and comparable to that in the general population. Our study clarifies that DP is not linked to colour perception deficits and constrains theories of DP that seek to account for a larger range of visual deficits beyond face recognition.

Face individual identity recognition: a potential endophenotype in autism.

BACKGROUND: Face individual identity recognition skill is heritable and independent of intellectual ability. Difficulties in face individual identity recognition are present in autistic individuals and their family members and are possibly linked to oxytocin polymorphisms in families with an autistic child. While it is reported that developmental prosopagnosia (i.e., impaired face identity recognition) occurs in 2-3% of the general population, no prosopagnosia prevalence estimate is available for autism. Furthermore, an autism within-group approach has not been reported towards characterizing impaired face memory and to investigate its possible links to social and communication difficulties. METHODS: The present study estimated the prevalence of prosopagnosia in 80 autistic adults with no intellectual disability, investigated its cognitive characteristics and links to autism symptoms' severity, personality traits, and mental state understanding from the eye region by using standardized tests and questionnaires. RESULTS: More than one third of autistic participants showed prosopagnosia. Their face memory skill was not associated with their symptom's severity, empathy, alexithymia, or general intelligence. Face identity recognition was instead linked to mental state recognition from the eye region only in autistic individuals who had prosopagnosia, and this relationship did not depend on participants' basic face perception skills. Importantly, we found that autistic participants were not aware of their face memory skills. LIMITATIONS: We did not test an epidemiological sample, and additional work is necessary to establish whether these results generalize to the entire autism spectrum. CONCLUSIONS: Impaired face individual identity recognition meets the criteria to be a potential endophenotype in autism. In the future, testing for face memory could be used to stratify autistic individuals into genetically meaningful subgroups and be translatable to autism animal models.

[Congenital amusia and its effects on non-musical skills]. / Amusia congénita y sus efectos en habilidades no musicales.

INTRODUCTION: Congenital amusia is a specific condition in which the individual is unable to recognise tonal variations in a piece of musical. This cannot be explained by a previous brain injury, hearing loss, cognitive deficit, socio-affective disorder or lack of environmental stimulation. The current estimated prevalence is 1.5% of the world population, with a significant genetic component among those who suffer from it. It has been claimed that certain cognitive abilities in the emotional, spatial and language fields may be affected in people with amusia. AIM: To review the literature describing the effects on non-musical skills that may coexist in individuals with congenital amusia. DEVELOPMENT: Several neuroimaging studies have observed morphological and functional changes in the temporal lobe, as well as in the white matter connections between the superior temporal gyrus and the inferior frontal gyrus. From these affected regions, there may be a deficit in cognitive skills related to adjacent areas. CONCLUSIONS: Congenital amusia has been associated with poor performance in different non-musical cognitive skills, such as visuospatial processing, language processing, reading difficulties, face recognition and emotional aspects.

TITLE: Amusia congénita y sus efectos en habilidades no musicales.Introducción. La amusia congénita es una condición específica en la que el individuo afectado es incapaz de reconocer variaciones tonales en las piezas musicales. Esto no puede explicarse por una lesión encefálica previa, una pérdida auditiva, un déficit cognitivo, un trastorno socioafectivo o una falta de estimulación ambiental. Actualmente se estima una prevalencia del 1,5% de la población mundial, con un importante componente genético entre los afectados. Se ha descrito que en las personas con amusia puede haber afectación de ciertas habilidades cognitivas en el campo emocional, espacial y del lenguaje. Objetivo. Revisar la bibliografía donde se describen los efectos en las habilidades no musicales que pueden coexistir en individuos con amusia congénita. Desarrollo. Varios estudios de neuroimagen han permitido observar cambios morfológicos y funcionales en el lóbulo temporal, así como en las conexiones de la sustancia blanca entre el giro temporal superior y el giro frontal inferior. Partiendo de estas regiones afectadas, podría existir un déficit en habilidades cognitivas relacionadas con áreas adyacentes. Conclusiones. La amusia congénita se ha relacionado con un pobre desempeño en diferentes habilidades cognitivas no musicales, como el procesamiento visuoespacial, el procesamiento del lenguaje, alteraciones de la lectura, el reconocimiento de rostros y aspectos emocionales.

Does developmental prosopagnosia impair identification of other-ethnicity faces?

Current approaches to the diagnosis of developmental prosopagnosia emphasise the perception and identification of same-ethnicity faces. This convention ensures that perceptual impairment arising from developmental prosopagnosia can be distinguished from problems arising from a lack of visual experience with particular facial ethnicities - the so-called 'Other-Ethnicity Effect'. The present study sought to determine whether the perceptual difficulties seen in developmental prosopagnosia - diagnosed using same-ethnicity faces - extend to other-ethnicity faces. First, we sought to determine whether a group of Caucasian developmental prosopagnosics (N = 15) and typical Caucasian controls (N = 30) had similar experience with same- and other-ethnicity faces during development. All participants therefore completed a contact questionnaire that enquired about their experience of Caucasian, Black, and East Asian faces, at different developmental stages. Importantly, the two groups described very similar levels of visual experience with other-ethnicity faces. Second, we administered a sequential matching task to measure participants' ability to discriminate same- (Caucasian) and other-ethnicity (Black, East Asian) faces. Relative to the experience-matched controls, the prosopagnosics were less accurate at discriminating both same- and other-ethnicity faces, and we found no evidence of disproportionate impairment for same-ethnicity faces. Given that the prosopagnosics and controls had similar opportunity to develop visual expertise for other-ethnicity faces, these results indicate that developmental prosopagnosia impairs recognition of both same- and other-ethnicity faces. The fact that developmental prosopagnosia affects the perception of both same- and other-ethnicity faces suggests that different facial ethnicities engage similar visual processing mechanisms. Our findings support the view that susceptibility to developmental prosopagnosia, and a lack of contact with other-ethnicity faces, contribute independently to the poor recognition of other-ethnicity faces.

Perception of musical pitch in developmental prosopagnosia.

Studies of developmental prosopagnosia have often shown that developmental prosopagnosia differentially affects human face processing over non-face object processing. However, little consideration has been given to whether this condition is associated with perceptual or sensorimotor impairments in other modalities. Comorbidities have played a role in theories of other developmental disorders such as dyslexia, but studies of developmental prosopagnosia have often focused on the nature of the visual recognition impairment despite evidence for widespread neural anomalies that might affect other sensorimotor systems. We studied 12 subjects with developmental prosopagnosia with a battery of auditory tests evaluating pitch and rhythm processing as well as voice perception and recognition. Overall, three subjects were impaired in fine pitch discrimination, a prevalence of 25% that is higher than the estimated 4% prevalence of congenital amusia in the general population. This was a selective deficit, as rhythm perception was unaffected in all 12 subjects. Furthermore, two of the three prosopagnosic subjects who were impaired in pitch discrimination had intact voice perception and recognition, while two of the remaining nine subjects had impaired voice recognition but intact pitch perception. These results indicate that, in some subjects with developmental prosopagnosia, the face recognition deficit is not an isolated impairment but is associated with deficits in other domains, such as auditory perception. These deficits may form part of a broader syndrome which could be due to distributed microstructural anomalies in various brain networks, possibly with a common theme of right hemispheric predominance.

Developmental prosopagnosia with concurrent topographical difficulties: A case report and virtual reality training programme.

Several neuropsychological case studies report brain-damaged individuals with concurrent impairments in face recognition (i.e., prosopagnosia) and topographical orientation. Recently, individuals with a developmental form of topographical disorientation have also been described, and several case reports of individuals with developmental prosopagnosia provide anecdotal evidence of concurrent navigational difficulties. Clearly, the co-occurrence of these difficulties can exacerbate the negative psychosocial consequences associated with each condition. This paper presents the first detailed case report of an individual (FN) with developmental prosopagnosia alongside difficulties in topographical orientation. FN's performance on an extensive navigational battery indicated that she primarily has difficulties in the formation and retrieval of cognitive maps. We then evaluated the effectiveness of a short-term virtual reality training programme and found that she is able to form a cognitive map of a particular environment following intense overlearning. Surprisingly, FN's performance on a face recognition task also improved following training. While the latter finding was unexpected and requires further exploration, the training programme reported here may help to alleviate some of the compounded negative psychosocial consequences that are associated with difficulties in finding both locations and people.

Visual crowding in pure alexia and acquired prosopagnosia.

Visual crowding is a phenomenon that impairs object recognition when the features of an object are positioned too closely together. Crowding limits recognition in normal peripheral vision and it has been suggested to be the core deficit in visual agnosia, leading to a domain-general deficit in object recognition. Using a recently developed tool, we test whether crowding is the underlying deficit in four patients with category specific agnosias: Two with pure alexia and two with acquired prosopagnosia. We expected all patients to show abnormal crowding. We find that the two patients with acquired prosopagnosia show abnormal crowding effects in foveal vision, while the pure alexic patients do not, and that this constitutes a significant dissociation. Thus, abnormal crowding cannot explain all cases of visual agnosia. Much recent work has focused on similarities between pure alexia and acquired prosopagnosia. Here we show a difference in a basic visual mechanism-visual crowding.

Face working memory deficits in developmental prosopagnosia: Tests of encoding limits and updating processes.

Developmental prosopagnosia (DP) is a condition in which individuals experience life-long problems recognising faces. In recent years, unpacking the nature of the impairments of this population has been the focus of numerous studies. One focus has been on the nature of face-based memory impairments for such individuals, with the onus being mainly on long-term memory deficits. Far fewer have considered the nature of face-based working memory (WM) impairments for DP cases, and the current study seeks to address this. One recent WM study (Shah et al., 2015) reported that the maintenance of faces over time in WM was spared among DPs, and argued instead that face encoding was limited in some way. Here we further explore the nature of face-based WM impairments in DP across two experiments designed to probe encoding limits (Experiment 1) and WM updating processes (Experiment 2). In Experiment 1 we manipulated the number of faces (1-4) to encode into WM and presented these simultaneously. We reasoned that if face encoding among DPs was inefficient or imprecise, then increasing encoding demands (WM load) would disproportionately impair WM accuracy compared to controls. However, we found that DP cases were consistently poorer than controls across all face load conditions, suggesting that front-end encoding problems are only part of the deficit. In Experiment 2, to measure updating four faces were shown sequentially for encoding into WM and accuracy was analysed as a function of whether the test face had been presented first, second, third or last in the encoding sequence. DPs had significantly poorer WM than controls for later faces but not the first face encoded in the sequence, and showed an attenuated recency effect. To account for these findings, we discuss the potential role of comparison processes at retrieval, impairments in configural face processing, and the impact of noise in the face identification system of individuals with DP.

Impaired processing of facial happiness, with or without awareness, in developmental prosopagnosia.

Developmental prosopagnosia (DP) is associated with severe, lifelong deficits in face recognition, with such cases often cited as support for a dissociation between the processing of facial identity and emotion. Here we examine the evidence against this dissociation and propose that the processing of facial happiness, either with or without awareness, is actually integrated within the same neural network involved in facial identity recognition. We also test this hypothesis on a group of DP cases and neurotypical controls (NT) by adapting them to expressionless neutral faces, intact happy faces and hybrid faces. Despite these hybrid faces being explicitly identified as expressionless due to their higher spatial frequencies taken from a neutral face, their low spatial frequencies convey happy facial expressions that participants are unaware of. After adaptation, participants were asked to judge the facial expressions of face stimuli that were morphed incrementally in varying degrees of sad through to happy. Both groups exhibited emotion adaptation aftereffects to the intact happy faces, although this effect was smaller in DP. Whereas NT produced emotion adaptation aftereffects without awareness of the happy emotion in the hybrid faces; as a group, those with DP did not. Furthermore, our DP cases also exhibited deficits in judging the emotion of the happiest morphed test faces. Our results indicate that the processing of happy facial expressions, with or without awareness, is likely integrated within the face recognition network. We hypothesise that the previously identified abnormalities in the fusiform gyrus in those with DP is the most likely structure responsible for these deficits.

The cognitive and neural basis of developmental prosopagnosia.

Developmental prosopagnosia (DP) is a severe impairment of visual face recognition in the absence of any apparent brain damage. The factors responsible for DP have not yet been fully identified. This article provides a selective review of recent studies investigating cognitive and neural processes that may contribute to the face recognition deficits in DP, focusing primarily on event-related brain potential (ERP) measures of face perception and recognition. Studies that measured the face-sensitive N170 component as a marker of perceptual face processing have shown that the perceptual discrimination between faces and non-face objects is intact in DP. Other N170 studies suggest that faces are not represented in the typical fashion in DP. Individuals with DP appear to have specific difficulties in processing spatial and contrast deviations from canonical upright visual-perceptual face templates. The rapid detection of emotional facial expressions appears to be unaffected in DP. ERP studies of the activation of visual memory for individual faces and of the explicit identification of particular individuals have revealed differences between DPs and controls in the timing of these processes and in the links between visual face memory and explicit face recognition. These observations suggest that the speed and efficiency of information propagation through the cortical face network is altered in DP. The nature of the perceptual impairments in DP suggests that atypical visual experience with the eye region of faces over development may be an important contributing factor to DP.

Face matching impairment in developmental prosopagnosia.

Developmental prosopagnosia (DP) is commonly referred to as 'face blindness', a term that implies a perceptual basis to the condition. However, DP presents as a deficit in face recognition and is diagnosed using memory-based tasks. Here, we test face identification ability in six people with DP, who are severely impaired on face memory tasks, using tasks that do not rely on memory. First, we compared DP to control participants on a standardized test of unfamiliar face matching using facial images taken on the same day and under standardized studio conditions (Glasgow Face Matching Test; GFMT). Scores for DP participants did not differ from normative accuracy scores on the GFMT. Second, we tested face matching performance on a test created using images that were sourced from the Internet and so varied substantially due to changes in viewing conditions and in a person's appearance (Local Heroes Test; LHT). DP participants showed significantly poorer matching accuracy on the LHT than control participants, for both unfamiliar and familiar face matching. Interestingly, this deficit is specific to 'match' trials, suggesting that people with DP may have particular difficulty in matching images of the same person that contain natural day-to-day variations in appearance. We discuss these results in the broader context of individual differences in face matching ability.

Extrañamiento y delirio / Estrangement and delusion

El síndrome de Capgras es una entidad nosológica estable, clasificada dentro de los síndromes de falsa identificación delirante. Hasta la fecha, ha servido para describir clínicamente los síntomas de interpretación delirante y percepción delirante, por un lado, y para elaborar los modelos neuropsicológicos de la prosopagnosia y apreciación de la identidad y familiaridad, por otro. Se propone un déficit secuencial en el sentido de familiaridad como el proceso subyacente desde el extrañamiento hasta el delirio, definiéndose este como el resultado de un intento fallido de la pasividad por restituir la coherencia afectiva de la experiencia (AU)

Capgras syndrome is a well-defined nosological unit, classified into the delusional misidentification syndromes. It has until now provided an empirical ground for the clinical description of delusional interpretation and delusional perception. It has also been used for the neuropsychological modelling of prosopagnosia, identity and familiarity appreciation. A sequential deficit in the sense of familiarity is proposed as the underlying process taking place from estrangement to delusion, which is conceived as a failure of passivity in putting back the affective coherence of experience (AU)

Altered spontaneous neural activity in the occipital face area reflects behavioral deficits in developmental prosopagnosia.

Individuals with developmental prosopagnosia (DP) exhibit severe difficulties in recognizing faces and to a lesser extent, also exhibit difficulties in recognizing non-face objects. We used fMRI to investigate whether these behavioral deficits could be accounted for by altered spontaneous neural activity. Two aspects of spontaneous neural activity were measured: the intensity of neural activity in a voxel indexed by the fractional amplitude of spontaneous low-frequency fluctuations (fALFF), and the connectivity of a voxel to neighboring voxels indexed by regional homogeneity (ReHo). Compared with normal adults, both the fALFF and ReHo values within the right occipital face area (rOFA) were significantly reduced in DP subjects. Follow-up studies on the normal adults revealed that these two measures indicated further functional division of labor within the rOFA. The fALFF in the rOFA was positively correlated with behavioral performance in recognition of non-face objects, whereas ReHo in the rOFA was positively correlated with processing of faces. When considered together, the altered fALFF and ReHo within the same region (rOFA) may account for the comorbid deficits in both face and object recognition in DPs, whereas the functional division of labor in these two measures helps to explain the relative independency of deficits in face recognition and object recognition in DP.

Localization and patterns of Cerebral dyschromatopsia: A study of subjects with prospagnosia.

OBJECTIVE: Cerebral dyschromatopsia is sometimes associated with acquired prosopagnosia. Given the variability in structural lesions that cause acquired prosopagnosia, this study aimed to investigate the structural correlates of prosopagnosia-associated dyschromatopsia, and to determine if such colour processing deficits could also accompany developmental prosopagnosia. In addition, we studied whether cerebral dyschromatopsia is typified by a consistent pattern of hue impairments. METHODS: We investigated hue discrimination in a cohort of 12 subjects with acquired prosopagnosia and 9 with developmental prosopagnosia, along with 42 matched controls, using the Farnsworth-Munsell 100-hue test. RESULTS: We found impaired hue discrimination in six subjects with acquired prosopagnosia, five with bilateral and one with a unilateral occipitotemporal lesion. Structural MRI analysis showed maximum overlap of lesions in the right and left lingual and fusiform gyri. Fourier analysis of their error scores showed tritanopic-like deficits and blue-green impairments, similar to tendencies displayed by the healthy controls. Three subjects also showed a novel fourth Fourier component, indicating additional peak deficits in purple and green-yellow regions. No subject with developmental prosopagnosia had impaired hue discrimination. CONCLUSIONS: In our subjects with prosopagnosia, dyschromatopsia occurred in those with acquired lesions of the fusiform gyri, usually bilateral but sometimes unilateral. The dyschromatopsic deficit shows mainly an accentuation of normal tritatanopic-like tendencies. These are sometimes accompanied by additional deficits, although these could represent artifacts of the testing procedure.

Agnosias visuales / Visual agnosia

Las agnosias visuales se definen como una alteración en la capacidad de reconocer objetos con la vista, en ausencia de pérdida de agudeza visual o disfunción cognitiva que explique esta alteración. Están producidas por lesiones de la corteza visual asociativa, respetando la corteza visual primaria. Existen 2 vías principales de procesamiento de la información visual: la vía ventral, encargada del reconocimiento de objetos, y la vía dorsal, encargada de su localización en el espacio. Las agnosias visuales pueden, por tanto, dividirse en 2 grandes grupos dependiendo de cuál de las 2 vías esté lesionada. El objetivo de este artículo es realizar una revisión narrativa sobre los diferentes síndromes agnósicos visuales, incluyendo los últimos avances realizados en algunos de ellos (AU)

Visual agnosia is defined as an impairment of object recognition, in the absence of visual acuity or cognitive dysfunction that would explain this impairment. This condition is caused by lesions in the visual association cortex, sparing primary visual cortex. There are 2 main pathways that process visual information: the ventral stream, tasked with object recognition, and the dorsal stream, in charge of locating objects in space. Visual agnosia can therefore be divided into 2 major groups depending on which of the two streams is damaged. The aim of this article is to conduct a narrative review of the various visual agnosia syndromes, including recent developments in a number of these syndromes (AU)