Explore the vast range of titles available.

Developmental prosopagnosia is characterized by severe, lifelong difficulties when recognizing facial identity. Unfortunately, the most common diagnostic assessment (Cambridge Face Memory Test) misses 50–65% of individuals who believe that they have this condition. This results in such excluded cases’ absence from scientific knowledge, effect sizes of impairment potentially overestimated, treatment efficacy underrated, and may elicit in them a negative experience of research. To estimate their symptomology and group-level impairments in face processing, we recruited a large cohort who believes that they have prosopagnosia. Matching prior reports, 56% did not meet criteria on the Cambridge Face Memory Test. However, the severity of their prosopagnosia symptoms and holistic perception deficits were comparable to those who did meet criteria. Excluded cases also exhibited face perception and memory impairments that were roughly one standard deviation below neurotypical norms, indicating the presence of objective problems. As the prosopagnosia index correctly classified virtually every case, we propose it should be the primary method for providing a diagnosis, prior to subtype categorization. We present researchers with a plan on how they can analyze these excluded prosopagnosia cases in their future work without negatively impacting their traditional findings. We anticipate such inclusion will enhance scientific knowledge, more accurately estimate effect sizes of impairments and treatments, and identify commonalities and distinctions between these different forms of prosopagnosia. Owing to their atypicalities in visual perception, we recommend that the prosopagnosia index should be used to screen out potential prosopagnosia cases from broader vision research.

Prosopagnosics have impaired face recognition, but make relatively normal responses to face stimuli in core brain regions for face recognition. The authors now report that it is the connectivity among these regions that is being disrupted in the disorder. Using diffusion tensor imaging and tractography, we found that a disruption in structural connectivity in ventral occipito-temporal cortex may be the neurobiological basis for the lifelong impairment in face recognition that is experienced by individuals who suffer from congenital prosopagnosia. Our findings suggest that white-matter fibers in ventral occipito-temporal cortex support the integrated function of a distributed cortical network that subserves normal face processing.

Behavioral evaluation of face identity recognition (FIR) ability has been performed with images for decades but remains subject to challenges regarding the stimuli and tasks used as well as the measured variables. Here we validate two simple nonverbal tests of FIR with ambient natural face images in neurotypical individuals and the well-documented brain-damaged case of prosopagnosia PS. In the first task, participants must select a famous identity among 3 simultaneously presented pictures. While neurotypical individuals scored almost at ceiling, PS was at chance level. In contrast, she was flawless at the same task with written names. The second task requires matching different views of familiar or unfamiliar faces for their identity against one distractor face, at upright or inverted orientation. While performing well above chance level, PS was significantly impaired and slowed down compared to neurotypical controls. Moreover, unlike controls, she showed no advantage for familiar or upright faces. Altogether, these simple behavioral FIR tests present with numerous advantages in terms of validity (i.e., natural images, lack of response biases, familiarity and inversion effects) and sensitivity (i.e., high contrast between patients and controls), making them particularly advantageous to rapidly evaluate the integrity of this function in normal and pathological populations.

The faces we see in daily life exist on a continuum of familiarity, ranging from personally familiar to famous to unfamiliar faces. Thus, when assessing face recognition abilities, adequate evaluation measures should be employed to discriminate between each of these processes and their relative impairments. We here developed the Italian Famous Face Test (IT-FFT), a novel assessment tool for famous face recognition in typical and clinical populations. Normative data on a large sample (N = 436) of Italian individuals were collected, assessing both familiarity ( d′ ) and recognition accuracy. Furthermore, this study explored whether individuals possess insights into their overall face recognition skills by correlating the Prosopagnosia Index-20 (PI-20) with the IT-FFT; a negative correlation between these measures suggests that people have a moderate insight into their face recognition skills. Overall, our study provides the first online-based Italian test for famous faces (IT-FFT), a test that could be used alongside other standard tests of face recognition because it complements them by evaluating real-world face familiarity, providing a more comprehensive assessment of face recognition abilities. Testing different aspects of face recognition is crucial for understanding both typical and atypical face recognition.

Developmental prosopagnosia (DP) is characterised by a severe and relatively selective deficit in face recognition, in the absence of neurological injury. Because public and professional awareness of DP is low, many adults and children are not identified for formal testing. This may partly result from the lack of appropriate screening tools that can be used by non-experts in either professional or personal settings. To address this issue, the current study sought to (a) explore when DP can first be detected in oneself and another, and (b) identify a list of the condition’s everyday behavioural manifestations. Questionnaires and interviews were administered to large samples of adult DPs, their unaffected significant others, and parents of children with the condition; and data were analysed using inductive content analysis. It was found that DPs have limited insight into their difficulties, with most only achieving realisation in adulthood. Nevertheless, the DPs’ reflections on their childhood experiences, together with the parental responses, revealed specific indicators that can potentially be used to spot the condition in early childhood. These everyday hallmark symptoms may aid the detection of individuals who would benefit from objective testing, in oneself (in adults) or another person (for both adults and children).

We tested 4 people who claimed to have significantly better than ordinary face recognition ability. Exceptional ability was confirmed in each case. On two very different tests of face recognition, all 4 experimental subjects performed beyond the range of control subject performance. They also scored significantly better than average on a perceptual discrimination test with faces. This effect was larger with upright than with inverted faces, and the 4 subjects showed a larger “inversion effect” than did control subjects, who in turn showed a larger inversion effect than did developmental prosopagnosics. This result indicates an association between face recognition ability and the magnitude of the inversion effect. Overall, these “super-recognizers” are about as good at face recognition and perception as developmental prosopagnosics are bad. Our findings demonstrate the existence of people with exceptionally good face recognition ability and show that the range of face recognition and face perception ability is wider than has been previously acknowledged.

Prosopagnosia is a significant symptom observed in the middle and late stages of Alzheimer's disease (AD), which severely affects patients and their families' daily life. Our study employed an occluded face delay matching paradigm (OFDM) to investigate the progression of face perception and memory, and the underlying neural mechanisms in individuals with healthy aging, mild cognitive impairment (MCI), and AD. We enrolled 180 participants, including 60 cognitively normal (CN) individuals, 69 MCI, and 51 AD patients. We combined the OFDM task and electroencephalogram (EEG) recordings to explore the temporal dynamics of face encoding, maintenance, and retrieval. Participants also underwent neuropsychological assessments and testing for cerebrospinal fluid amyloid and tau markers. Behavioral performance shows a clear gradient descent across the three groups, diagnostic models based on task performance yielded an area under the curve (AUC) value of 0.79 (95% CI: 0.72-0.86, p < 0.001). The EEG results further revealed that in patients with AD, impairments in face processing were associated not only with compromised face memory (the negative slow wave, NSW: p = 0.0029) but also with deficits in both early (P1: p = 0.0277) and later stages of face processing (N170: p = 0.0335, P2: p = 0.0149). More importantly, face impairment in AD continuum was already detectable in the MCI stage. Patients with MCI showed abnormalities in early face encoding (P1: p = 0.0277) and perception (N170: p = 0.0335), yet they preserved certain higher-level face processing abilities (P2: p = 0.3016) and aspects of face memory (NSW: p = 0.0974). Furthermore, impaired face-perception in MCI and AD was characterized by decreased theta and alpha band power and synchronization. The preservation of face memory in MCI was linked to the activation of alpha power. Additionally, the adverse impact of T-Tau on Mini-Mental State Examination (MMSE) scores was partially mediated by theta oscillation (indirect effect = 0.00185, 95% CI: 0.000148 - 0.028). This study indicates that our OFDM task effectively differentiates between different stages of cognitive impairment. As the pre-stage of AD, MCI patients have relatively preserved high-level face cognition and face memory despite early face processing deficits, highlighting potential targets for early intervention and neural regulation in AD.

Developmental prosopagnosia (DP) is characterised by deficits in face identification. However, there is debate about whether these deficits are primarily perceptual, and whether they extend to other face processing tasks (e.g., identifying emotion, age, and gender; detecting faces in scenes). In this study, 30 participants with DP and 75 controls completed a battery of eight tasks assessing four domains of face perception (identity; emotion; age and gender; face detection). The DP group performed worse than the control group on both identity perception tasks, and one task from each other domain. Both identity perception tests uniquely predicted DP/control group membership, and performance on two measures of face memory. These findings suggest that deficits in DP may arise from issues with face perception. Some non-identity tasks also predicted DP/control group membership and face memory, even when face identity perception was accounted for. Gender perception and speed of face detection consistently predicted unique variance in group membership and face memory; several other tasks were only associated with some measures of face recognition ability. These findings indicate that face perception deficits in DP may extend beyond identity perception. However, the associations between tasks may also reflect subtle aspects of task demands or stimuli.

Face recognition is strongly influenced by the processing of orientation structure in the face image. Faces are much easier to recognize when they are filtered to include only horizontally oriented information compared with vertically oriented information. Here, we investigate whether preferences for horizontal information in faces are related to face recognition abilities in a typical sample (Experiment 1), and whether such preferences are lacking in people with developmental prosopagnosia (DP; Experiment 2). Experiment 1 shows that preferences for horizontal face information are linked to face recognition abilities in a typical sample, with weak evidence of face-selective contributions. Experiment 2 shows that preferences for horizontal face information are comparable in control and DP groups. Our study suggests that preferences for horizontal face information are related to variations in face recognition abilities in the typical range, and that these preferences are not aberrant in DP.