Face Recognition Deficits in a Patient With Alzheimer's Disease: Amnesia or Agnosia? The Importance of Electrophysiological Markers for Differential Diagnosis

Abstract

Face recognition deficits are frequently reported in Alzheimer's disease (AD) and often attributed to memory impairment. However, it has been hypothesized that failure in identifying familiar people could also be due to deficits in higher-level perceptual processes, since there is evidence showing a reduced inversion effect for faces but not for cars in AD. To address the involvement of these higher processes, we investigated event-related potential (ERP) neural correlates of faces in a patient with AD showing a face recognition deficit. Eight healthy participants were tested as a control group. Participants performed different tasks following the stimulus presentation. In experiment 1, they should indicate whether the stimulus was either a face or a house or a scrambled image. In experiments 2 and 3, they should discriminate between upright and inverted faces (in experiment 2, stimuli were faces with neutral or fearful expressions, while in experiment 3, stimuli were famous or unfamiliar faces). Electrophysiological results reveal that the typical face-specific modulation of the N170 component, which is thought to reflect the structural encoding of faces, was not present in patient MCG, despite being affected by the emotional content of the face implicitly processed by MCG. Conversely, the N400 component, which is thought to reflect the recruitment of the memory trace of the face identity, was found to be implicitly modulated in MCG. These results may identify a possible role for gnosic processes in face recognition deficits in AD and suggest the importance of adopting an integrated approach to the AD diagnosis while considering electrophysiological markers.

Eye movement patterns during viewing face images with neutral expressions in patients with early‐stage Alzheimer's disease and amnestic mild cognitive impairment

“…Consistent with the neuroimaging findings above, a lot of studies have shown that memory of unfamiliar faces and recognition of facial expressions skills are impaired in AD (Güntekin et al., 2019 ; Lavallée et al., 2016 ; Mazzi et al., 2020 ; Seelye et al., 2009 ; Spoletini et al., 2008 ; Werheid & Clare, 2007 ). In addition, poor face memory and recognition of facial expression performance have been demonstrated in patients with aMCI (Kawagoe et al., 2017 ; Nguyen et al., 2014 ; Seelye et al., 2009 ; Teng et al., 2007 ).…”

“…Although the eye is the most important part of the face, in our study, a decrease was found in the number of fixations and the duration of of AD (Güntekin et al, 2019;Lavallée et al, 2016;Mazzi et al, 2020;Seelye et al, 2009;Spoletini et al, 2008;Werheid & Clare, 2007). These impairments may be related to the inefficient face-scanning found in our study.…”

Variation in Group Composition Alters an Early-Stage Social Phenotype in hAPP-Transgenic J20 Mice

“…Besides problems in cognitive functions including memory, attention, and orientation, patients with dementia often experience behavioral and psychological symptoms [ 9 ]. These include problems with face recognition [ 10 ], emotion recognition [ 11 ], apathy [ 12 ], and social functioning in everyday situations (e.g., initiating contact, expressing opinions) [ 11 ]. Thus, aberrant social behavior is both a risk factor and a symptom of AD.…”

Advances in Modeling Alzheimer's Disease In Vitro

“…AD is characterized by memory loss, agnosia, apraxia, aphasia, degradation of personality, loss of regulation of vital functions, and finally infectious disease leading to death in these patients. [2][3][4][5][6][7][8] Nearly 121 499 people died in AD due to complications in 2019. [1] The emergence of AD is reported to be associated with multiple risk factors including genetic and environmental sources, with progressing age being the most significant among them.…”