The Study of Face Processing in Social Anxiety Disorder Based on Face-Specific N170 Component

Hindawi
Journal of Healthcare Engineering
Volume 2022, Article ID 6003973, 10 pages
https://doi.org/10.1155/2022/6003973

Research Article
The Study of Face Processing in Social Anxiety Disorder Based on
Face-Specific N170 Component

 Xuejing Bi,1 Min Guo,2 Jianqin Cao ,1 and Yanhua Hao 3

 1
 Department of Nursing, Harbin Medical University, Daqing 163319, China
 2
 Academy of Electronic Information and Electrical Engineering, Xiamen Institute of Technology, Xiamen 361021, China
 3
 School of Health Management, Harbin Medical University, Harbin 150081, China

 Correspondence should be addressed to Jianqin Cao; cjq338@163.com and Yanhua Hao; hyh@ems.hrbmu.edu.cn

 Received 12 October 2021; Revised 1 December 2021; Accepted 2 December 2021; Published 7 January 2022

 Academic Editor: Deepak Kumar Jain

 Copyright © 2022 Xuejing Bi et al. This is an open access article distributed under the Creative Commons Attribution License,
 which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
 Although previous studies showed that social anxiety disorder (SAD) exhibits the attentional bias for angry faces, few studies
 investigated effective face recognition combined with event-related potential (ERP) technique in SAD patients, especially the
 treatment effect. This study examines the differences in face processing in SAD patients before and after treatment and healthy
 control people (H-group). High-density EEG scans were registered in response to emotional schematic faces, particularly in-
 terested in the face processing N170 component. Analysis of N170 amplitude revealed a larger N170 for P-group-pre in response
 to inverted and upright stimuli than H-group in the right hemisphere. The result of the intragroup t-test showed that N170 was
 delayed for inverted relative to upright faces only in P-group-post and H-group but not in P-group-pre. Remarkably, the results of
 ANOVAs manifested that emotional expression cannot modulate N170 for SAD patients. Besides, the N170-based asymmetry
 index (AI) was introduced to analyze the left- and right-hemisphere dominance of N170 for three groups. It was found that, with
 the improvement of patients’ treatment, the value of AIN170−base d presented a decreasing trend. These results together suggested
 that there was no inversion effect observed for patients with SAD. The change in the value of AIN170−base d can be used as potential
 electrophysiological markers for the diagnosis and treatment effects on patients with SAD.

1. Introduction [5]. In contrast, an EEG study showed blunted early dis-
 crimination on faces that have rejected or accepted them
Social anxiety disorder (SAD) is an anxiety disorder ac- [6]. Given the abnormality of SAD patients in face pro-
companied by both unusual physical and mental symp- cessing, the early-stage neural responses of patients with
toms, mainly characterized by intense fear when facing SAD may be different compared with healthy individuals
social interaction context or public places. Previous studies and may also change with treatment.
have indicated that patients with SAD are associated with Face perception plays an indispensable role in both social
deficits in social cognition, including several cognitive life and interpersonal communication. Even normal newborn
biases such as expectation bias, attention bias, memory babies tend to pay attention to face-related stimuli [7].
bias, and response bias to faces, even for neutral faces [1, 2]. Damaging the face-related neural mechanism involved in face
For example, patients with SAD exhibit a more robust recognition can seriously affect everyday life. At the same time,
amygdala activation in response to neutral faces than other studies have indicated that social anxiety disorders
healthy control individuals [3], while affective context can showed avoidant and escaped responses to faces with direct eye
modulate the processing of neutral faces for patients with contact [8, 9]. Recent research showed that cognitive-behav-
SAD [4]. Magnetoencephalography (MEG) study suggested ioral therapy can reduce the early visual processing of faces for
that patients with SAD show reduced N170 representing patients with social anxiety disorder [10]. Although consid-
early fusiform gyrus activity compared to healthy controls erable effort has been made to study the neural processing of

2 Journal of Healthcare Engineering

face-related information in mental disorders, including pro- were recruited from the Psychology Department of Affiliated
sopagnosia, autism spectrum disorders (ASD), and schizo- Hospital of Harbin Medical University, while 20 healthy
phrenia [11], the brain mechanism associated with face control (HC) participants were recruited through adver-
recognition in SAD has not been well studied. tisements. The patients with SAD were diagnosed using the
 Some electrophysiological studies employing ERPs validated Chinese translation of the Structured Clinical
provide a source of evidence for specialized brain processes Interview for Diagnostic and Statistical Manual of Mental
subserving face perception and recognition. In particular, Disorders, Fourth Edition (DSM-IV) (SCID-IV), the gold
N170 is described as a harmful component peaking at about standard for assessing SAD in China. Control participants
170 ms that is elicited by human faces [12, 13]. Because of the were demographically matched HCs with no history of
sensitive response to face stimulus, N170 is considered the DSM-IV psychiatric disorders. These individuals were also
specific component of face processing [14]. N170 as a classic screened using the SCID. All participants were right handed
face-specific component that reflects early-stage perception and reported no psychoactive substance abuse, no unstable
in the structural encoding of faces [15]. Since a study showed medical illness, and no past or current neurological illness.
that N170 is not affected by the familiarity of the faces [16], it The subjects’ anxiety symptoms were assessed using the Brief
can be inferred that the familiarity processing is earlier than Social Phobia Scale (BSPS) and the Interaction Anxiousness
the early facial structural encoding process [17]. The N170 Scale (IAS). All participants provided written informed
elicited by facial stimuli is mainly distributed on both sides consent for the experiment. Participants with SAD and the
of the posterior-temporal cortex. It mainly exhibits a larger matched HC were excluded because they dropped out of the
amplitude on the right side of the posterior-temporal regions therapy. We thus carried out the study using a sample of 12
[18, 19]. It is proposed that N170 elicited by words would patients with SAD and 12 HC participants. The groups did
show a left-hemisphere dominance [20], while face stimuli not differ in demographic characteristics. Compared to
elicited right-hemisphere dominance [21]. Except for up- those in the HC-group, participants in the SAD group re-
right faces, inverted faces have also been utilized as stimulus ported higher levels of social anxiety.
materials in face processing studies, which are supposed to Twelve patients with SAD (5 men and 7 women) are
destroy the configurational information related to face between ages 19 and 24 years old (M � 21.50, SD � 1.51) who
recognition [22]. In general, inverted faces delay the latency participated in the study. SAD patients were recruited by the
of N170, which is regarded as the main aspect of the N170 Harbin Medical University (Daqing, China). For the healthy
inversion effect [23, 24]. control (HC) groups, 12 subjects (7 men and 5 women) ranging
 Some related studies showed that patients with SAD in age from 18 to 25 years (M � 20.33, SD � 2.06) were recruited
manifest many traits similar to other disorders, such as through a website. There were no gender, age, and educational
schizophrenia individuals, ASD patients, excessive Internet level differences between patients with SAD and healthy
users (EIUs), and depressive patients [25]. In the early stage control subjects. All subjects were screened by trained experts
of face processing, characteristics of the N170 component using the fourth edition version of the Diagnostic and Statistical
revealed a lesion in EIUs or individuals with schizophrenia Manual of Mental Disorders (DSM-IV) [27]. Patients with
compared with normal individuals [11, 26]. The study also SAD were required to meet the criteria for social anxiety, while
found that the abnormal early face processing of SAD pa- control subjects were required to confirm the absence of
tients was related to their response bias to unfamiliar faces. psychopathology. Exclusion criteria for both SAD and control
found that abnormality of early face processing in patients subjects included bipolar disorder, schizophrenia, psychosis,
with SAD, which is associated with their response bias to delusional disorders, and an abnormal EEG. None of the SAD
stranger faces [6]. However, the associations between the patients and healthy people reached the criteria for elimination.
aforementioned cognitive biases are unclear. Previous re- Interaction Anxiousness Scale (IAS) [28] and the Brief
search on N170 in patients with SAD was mainly focused on Social Phobia Scale (BSPS) [29] were used to test the level of
the attentional bias of emotional expression but less on face social anxiety. The total score of scales reflects the severity of
recognition. Therefore, the primary purpose of this study the symptoms of SAD. A higher total score means a more
was to explore the differences in face processing mechanisms severe condition. The prepatient group exhibited signifi-
between normal individuals and SAD patients before and cantly higher scores (IAS: 58.00 ± 9.28, BSPS:42.33 ± 10.49)
after treatment by analyzing the N170 component. We also than HC-group (IAS: 30.58 ± 4.32, BSPS:7.25 ± 4.88), and the
expected to find an indicator that could evaluate the im- prepatient group exhibited significantly higher scores than
provement of patients’ condition. We conducted a passive the postpatient group (IAS: 43.83 ± 7.63, BSPS:
viewing upright and inverted emotional expression para- 21.58 ± 12.39).
digm. We hypothesized to explore abnormality in latency or
amplitude or the hemisphere effect of N170 in SAD.
 2.2. Stimulus Materials. The stimulus materials were a set of
2. Material and Methods black-and-white schematic face pictures consisting of happy,
 neutral, and sad expressions. Each emotional expression
2.1. Participants. The study was carried out following the included both upright and inverted faces. There were
Declaration of Helsinki, and the experimental protocols used eighteen pictures for each condition (happy-upright, happy-
were approved by the institutional review board (IRB) of the inverted, neutral-upright, neutral-inverted, sad-upright, and
Harbin Medical University. Twenty outpatients with SAD sad-inverted) (see Figure 1). Such stimulating materials have

Journal of Healthcare Engineering 3

 (a)

 button button …… button button button ……

 300 ms 300 ms 300 ms 300 ms 300 ms

 Training stage Formal stage
 (b)

 Figure 1: The stimulus materials of the experiment (a) and a schematic representation of the experimental protocol (b).

already been used in research related to face recognition the paradigm of passive viewing face pictures, which is most
[30, 31]. Moreover, schematic faces demonstrate the main commonly used in face recognition [32, 33]. The detailed
parts of a face enough to weaken gender differences in schematic diagram is illustrated in Figure 1(b). Each trial
human faces. started with a training stage; meanwhile, pictures of six kinds
 of expressions were randomly presented for 300 ms. Sub-
 sequently, participants were instructed to press the button
2.3. EEG Recording. Electroencephalogram (EEG) signals matching with the expression on a keyboard after sorting out
were recorded from a 64-channel EEG amplifier (Synamps2 the contents of the images. There was no time limit. The new
Compumedics Neuroscan) with a sampling rate of 1,000 Hz. round of the experiment would continue to start upon
Locations of electrodes followed the international 10–20 participants’ responses. After the training phase, the subjects
system. The impedance of all electrodes was kept below pressed the “SPACE” bar to start the formal experiment and
5 KΩ. An electrode placed on the vertex served as the ref- formatted the same as the training phase. For the formal
erence for online recording. The collected signals were re- experiment, the picture of each case was randomly repeated
referenced to the common average reference before further four times and 68 times for each condition.
processing.
 Notably, two datasets (before and one year after the
treatment, respectively) of each patient with SAD were 2.5. Data Analysis. The raw EEG data were filtered using the
recorded under the same experimental conditions. The cut off frequency of 30 Hz Chebyshev low-pass filter (4-order
treatment was conducted by a clinical psychologist and a IIR), which would weaken the powerline interference and
psychology teacher. Mainly, intensive intervention therapy EMG artifacts that are mainly above 30 Hz. Regardless, the
was performed lasting 12 weeks. The form of intervention remaining artifact-contaminated portions of the EEG were
was a combination of group intervention and individual manually identified and excluded from further analysis.
intervention. Patients were randomly assigned to an inter- Collected datasets consisted of patients before treatment
vention group consisting of 6 people. The group of cognitive (P-group-pre), one year after treatment (P-group-post), and
behavioral therapy was performed weekly, and the indi- healthy individuals (HC-group). The EEG was epoched
vidual intervention was performed once a week, that is, each offline from 50 ms before the beginning of the onset of the
patient completed 12 group therapy sessions and 12 indi- face to 500 ms after onset. In addition, epochs were averaged
vidual-therapy sessions. After one year, participants again for every subject and for every class of stimuli. The baseline
completed an EEG recording and a scale evaluation. was corrected using 50 ms before stimulus onset. What’s
 more, in this study N170 was identified as the most negative
 or negative ongoing peak between 106 and 192 from the
2.4. Experimental Paradigm. Stimulus presentation was grand-averaged waveform. To compare differences of
controlled by Eprime 2.0 (Psychology Software Tools, Inc.). emotional expression in similar subjects, repeated measures
Subjects were seated on a comfortable chair in front of the ANOVAs can examine specific effects or interactions.
screen. All subjects were asked to reduce the body’s The study of ERPs often used the asymmetry index (AI),
movement during the experiment to minimize the impact of to express asymmetry between the left and right brain
the electromyographic (EMG) artifacts. This study adopted hemispheres. AI is defined as AI � (L − R)/(L + R), where L

4 Journal of Healthcare Engineering

and R are the values of the special regions of the left and right emotional expression, longer N170 latency was observed at
hemispheres [6, 34]. Previous research concluded that the PO8 under upright conditions for P-group-pre compared to
response bias in individuals with SAD is resulted from P-group-post (p � 0.002) and for H-group than P-group-
impairments in early discrimination of social faces, as re- post (p � 0.002), but no significant difference was observed
flected by the absent early N170 differentiation effect, which between P-group-pre and HC-group. Moreover, in hemi-
was associated with their combined negative biases [6]. In sphere-independent analysis, except for P-group-pre, a
this study, the N170-based asymmetry index (AI) was in- longer N170 peak was elicited by inverted compared to
troduced to analyze the left- and right-hemisphere domi- upright faces within the other two groups (p � 0.04 and p �
nance of N170 for the three groups. For this experiment, 0.03 for P-group-post and HC-groups).
since EEG mapping was obtained by using the normalized
amplitude, AI was modified as follows:
 3.4. AI Index Treatment Effect. In terms of N170 amplitude
 1 N and latency, this study did not find the desired results
 AIN170−base d � Xleft − Xright , (1) reflecting the treatment effect. However, from P-group-pre
 N i�1
 to H-group the left-lateralized N170 was consistently en-
where N is the number of the electrode and Xleft and Xright hanced after treatment in posterior-temporal regions as
are the normalized N170 amplitude of specific range in left shown in Figure 2. Five symmetrical electrodes located in the
and right hemispheres. Different value of AIN170−base d in- posterior-temporal regions (PO7/PO8, PO5/PO6, P7/P8,
dicates the role that hemisphere dominance of N170 plays: P5/P6, and P3/P4) were taken one step further for examining
(1) as the value is positive, it indicates that the N170 is hemisphere dominance, and formula (1) was then used for
dominant of right hemisphere; (2) as the value approaches the next step. For this formula, N has a value of 5. The
zero, the left- and right-hemisphere dominance of N170 detailed values of AIN170−base d under inverted conditions or
closes to balance; and (3) as the value is negative, it dem- upright conditions are displayed in Table 2. According to
onstrates that the N170 is dominant in the left hemisphere. Table 2, it could be clearly seen that from the first to the third
 column, the values of AIN170−base d exhibited a decreasing
3. Results trend. When performing statistical analysis by using t-tests,
 significant differences were found in P-group-pre vs.
3.1. N170 Topographical Distribution and Waveforms. P-group-post (p � 0.04 (inverted) and p � 0.04 (upright),
EEG topographical mapping of N170 is displayed in Fig- respectively) and P-group-pre versus H-group (p � 0.01
ure 2, and the value of each electrode was worked out by (inverted) and p � 0.01 (upright), respectively) but not in
normalizing the average amplitude of a specific range. It P-group-post versus H-group.
could be seen that the right predominant N170 was mainly
concentrated in posterior-temporal regions. Because of the
topographical maps of N170, the electrodes of PO8 and PO7 3.5. Effects of Emotional Expression in SAD Patients. A three-
(see Figure 2) as the most conspicuous sites were selected for factor ANOVA with repeated measures that can contact the
further analysis. Moreover, Figures 3 and 4 depict the grand significant differences between multiple emotional expres-
mean ERP waveforms under inverted or upright conditions, sions was adopted. The factors were Hemisphere (2 levels:
respectively. This graph shows that the main ERP compo- left, right), Orientation (2 levels: inverted, upright), and
nents, including P1 and N170, were successfully induced and Emotional category (3 levels: happy, neutral, sad). The re-
further proved the rationality of this experimental protocol. sults showed that there were no significant main effects in
 latency (F (2.22) � 0.17, p � 0.85) or amplitude (F (1.19,
 13.04) � 0.09, p � 0.81) of N170 in P-group-pre when
3.2. N170 Amplitude. Irrespective of emotional expression, comparing different emotional expressions. Furthermore,
statistical tests were performed between groups according to there was no any interaction with emotional expression.
upright and inverted conditions. The results revealed sig-
nificantly enlarged N170 amplitude for P-group-pre relative 4. Discussions
to HC-group in inverted condition (p � 0.02) and upright
condition (p � 0.02) at electrode PO8 but not at electrode This study was conducted to study the differences in face
PO7. A similar conclusion was also obtained for P-group- processing mechanisms between patients with SAD before
post versus HC-group. P-group-post showed greater N170 and after treatment and healthy people when looking at
amplitude than HC-group in the right hemisphere both in upright and inverted emotional expressions. The main re-
inverted or upright stimuli (p � 0.01 and p � 0.004, re- sults came from ERPs elicited by faces especially include a
spectively). Furthermore, analysis including the expression negative potential N170, which is considered to be the most
factors showed no significant amplitude difference in the left persuasive component in face processing.
hemisphere and neither the right hemisphere.
 4.1. Processing Intensity of Early Face Recognition in SAD
3.3. N170 Latency for Different Groups. Table 1 depicts the Patients. The two groups, group with SAD (P-group-pre)
mean and standard error of N170 amplitude and latency for and HC-group, N170 amplitude, and latency were com-
inverted and upright conditions of PO7 and PO8. Across pared. It turned out that the P-group-pre of N170 amplitude

Journal of Healthcare Engineering 5

 P-group-pre P-group-post H-group

 Inverted

 -1 -0.5 0 0.5 1
 (a)
 P-group-pre P-group-post H-group

 Upright

 -1 -0.5 0 0.5 1
 (b)

Figure 2: (a) The grand-averaged N170 amplitude mapping under inverted conditions and (b) upright conditions. The topographic map on
the left was the prepatient group, and the middle and right for the postpatient group and the HP-group, respectively.

was significantly larger than for the H-group? In the right Irrespective of hemisphere, for both the P-group-post and
hemisphere under upright and inverted conditions. The H-group, the intragroup statistic test exhibited a significant
amplitude of N170 can reflect the processing intensity of difference when comparing N170 latency in upright faces
early face recognition. Therefore, these data provide evi- with inverted faces, while P-group-pre did not reveal any
dence that a greater processing intensity of SAD patients in differences in this respect. Therefore, it can be inferred that
the right hemisphere was responsible for the abnormalities there was no inversion effect in SAD patients. Given that the
during the process of early face recognition. In this regard, autism inversion effect was not observed before, this study
this study did not investigate the differences between assumes that patients with SAD may have the same face
P-group-post and H-group. The main reason was to get rid processing strategies as those with autism. Feature-based
of a certain degree of “expert effect” produced by previous processing methods different from the healthy people were
experiments on the impact of N170 amplitude [18]. adopted for individuals with ASD [38, 39].

4.2. Inversion Effect in SAD Patients. For face recognition, 4.3. Whether the Emotional Expression Can Modulate N170 in
the research on the inversion effect has always been a SAD Patients. The ANOVA was used to explore the effect of
popular topic for decades. Face inversion delays and/or emotional expression in SAD patients for P-group-pre in
enhances the N170 component [26]. Furthermore, previous follow-up studies. The results revealed that there is no sig-
literature has shown that gestalt-based schematic faces that nificant difference associated with the factor of emotion.
lack physiognomic components may inhibit a holistic per- Whether it can enhance the processing of emotional expression
ception of a face and do not trigger the analysis of the in patients has been controversial. Numerous studies hold that
components when the face is inverted [35]. Due to this SAD could lead to a general overactivation of the brain when
study’s usage of schematic faces as stimulus materials, it is processing any emotional faces [39]. On the contrary, other
understandable that the inversion effect did not manifest studies have demonstrated that SAD and emotional expression
itself in the facets of amplitude. In this study, the inversion are irrelevant. Studies have proved that scary faces (typical:
effect, therefore, showed up as a delay of N170. It is well angry) can induce specific responses in patients with SAD [40].
known that an inverted image disrupts the configurational The sad expression conveyed avoidance or seeking for pro-
information of face recognition. The accepted result is that tection without directly displaying hostility in the patients with
the latency of N170 in healthy people will have a noticeable SAD. The above may be one of the reasons why SAD patients
difference in upright faces related to inverted faces [36, 37]. are not sensitive to emotion in this study. In short, under the

6 Journal of Healthcare Engineering

 Inverted
 PO7 PO8

 2 2
 P-group-pre

 0 0
 µV

 µV
 -2 -2

 -50 0 100 200 300 400 500 -50 0 100 200 300 400 500
 ms ms
 (a)

 2 2
 P-group-post

 0 0
 µV
 µV

 -2 -2

 -50 0 100 200 300 400 500 -50 0 100 200 300 400 500
 ms ms
 (b)

 2 2
 H-group
 µV

 µV

 0 0

 -2 -2

 -50 0 100 200 300 400 500 -50 0 100 200 300 400 500
 ms ms
 Happy
 Neutral
 Sad
 (c)

Figure 3: Grand mean ERPs in response to happy, neutral, and sad faces for (a) prepatient group, (b) postpatient group, and (c) HP-group at
electrodes PO7 (left) and PO8 (right). The ERP was elicited by inverted stimuli.

same experimental protocol and stimulus materials, schematic especially the right hemisphere, can induce the maximum
faces of different emotional expressions cannot modulate N170 amplitude of N170. However, in this study, mainly a left-
in SAD patients. lateralized N170 was observed in H-group. A similar phe-
 nomenon was reported in some research studies adopting
 text-related stimuli [20]. In this regard, this study provided
4.4. The Change in Hemisphere Dominance during the two reasonable explanations. First of all, colorless and ex-
Treatment. Regarding the distribution of the central brain plicit stimulus materials did not activate the right hemi-
regions of N170 elicited by face-related materials, the general sphere, which is responsible for painting, geometry, and
conclusion is that posterior-temporal regions on both sides, other functions [41, 42]. Another line-shaped stimulating

Journal of Healthcare Engineering 7

 Upright
 PO7 PO8

 2 2
 P-group-pre

 0 0
 µV

 µV
 -2 -2

 -50 0 100 200 300 400 500 -50 0 100 200 300 400 500
 ms ms
 Happy
 Neutral
 Sad
 (a)

 2 2
 P-group-post

 0 0
 µV
 µV

 -2 -2

 -50 0 100 200 300 400 500 -50 0 100 200 300 400 500
 ms ms
 Happy
 Neutral
 Sad
 (b)

 2 2
 H-group

 0 0
 µV
 µV

 -2 -2

 -50 0 100 200 300 400 500 -50 0 100 200 300 400 500
 ms ms
 Happy
 Neutral
 Sad
 (c)

Figure 4: Grand mean ERPs in response to happy, neutral, and sad faces for (a) prepatient group, (b) postpatient group, and (c) HP-group at
electrodes PO7 (left) and PO8 (right). The ERP was elicited by upright stimuli.

8 Journal of Healthcare Engineering

 Table 1: Means (and standard deviations) for latency and amplitude of N170.
Electrode Condition Latency (ms) Amplitude (uV)
 Prepatient group
 Inverted faces 158.97 (13.34) −3.17 (2.20)
PO8
 Upright faces 154.47 (16.75) −3.12 (2.10)
 Inverted faces 154.58 (18.98) −2.93 (1.79)
PO7
 Upright faces 149.03 (18.38) −3.07 (1.99)
 Postpatient group
 Inverted faces 153.58 (18.86) −3.13 (1.74)
PO8
 Upright faces 144.83 (18.62) −3.34 (1.99)
 Inverted faces 147.75 (24.76) −3.03 (1.67)
PO7
 Upright faces 142.14 (22.87) −3.18 (1.50)
 HC-group
 Inverted faces 158.94 (14.00) −2.23 (1.15)
PO8
 Upright faces 153.92 (15.21) −2.21 (1.20)
 Inverted faces 160.00 (13.21) −3.19 (2.05)
PO7
 Upright faces 155.17 (14.59) −3.30 (2.21)

 Table 2: The values (and standard deviations) of AIN170−base d in three groups under inverted and upright conditions.
 Prepatient group Postpatient group HC-group
Inverted faces 0.1565 (0.39) 0.0115 (0.41) −0.0341 (0.42)
Upright faces 0.1420 (0.37) −0.0074 (0.43) −0.0412 (0.45)

material used in this study may be identified as Chinese AI and other approaches. Third, the main limitation is the
characters. For example, a round face is like a “口” word, and small sample size. It requires more participants and future
the eyes, nose, and mouth together make up “土” or “工” research to verify the conclusion.
word. On the contrary, a right-lateralized N170 was found in
P-group-pre. Unlike ordinary people, some studies reported Data Availability
that for patients with SAD, the suitable posterior-temporal
regions or right amygdala could be activated by emotional or The data used to support the findings of this study are
line-shaped faces (such as schematic faces) [10, 28, 43]. available from the author upon request.
Based on the findings in this study, we first put forward that
under inverted conditions or upright conditions, the change Ethical Approval
in the value of AIN170−base d can be used as an indicator of
condition improvement in SAD patients. All procedures of this study were in line with the interna-
 tional ethical code of ethical conduct for biomedical research
5. Conclusions involving human subjects (CIOMS) and the Declaration of
 Helsinki. The study was carried out in accordance with the
To sum up, according to a protocol of face recognition, this Declaration of Helsinki, and the experimental protocols
study adds new value that under inverted conditions or were approved by the Institutional Review Board (IRB) of
upright conditions the change in the value of AIN170−base d the Harbin Medical University.
can be used as an electrophysiological indicator of treatment
improvement in patients with SAD. Besides, this study re- Consent
veals no inversion effect in patients with SAD, suggesting
that abnormal facial perception in patients with SAD may be All participants provided written informed consent for the
similar to other patients with dysfunctional social ability, experiment.
e.g., autism.
 There are several limitations in this study. First, the Conflicts of Interest
behavioral data of reaction time were not recorded. The
experiment does not mark when subjects press the button, so The authors declare no conflicts of interest.
the reaction time of different expressions cannot be calcu-
lated. Second, while this study puts forward that similarities Authors’ Contributions
in a face processing stage may exist between patients with
SAD and with ASD, no further experiment was designed to Xuejing Bi mainly writes the first draft, Min Guo is re-
address it. It requires future research to understand it. sponsible for data analysis, and Xuejing Bi and Min Guo
However, the AI approach is a way to illustrate our con- contributed equally. Jianqin Cao is responsible for research
clusion, and the next step is to explore the difference between and design, and Yanhua Hao is responsible for proofreading.

Journal of Healthcare Engineering 9

Acknowledgments [16] D. Carmel and S. Bentin, “Domain specificity versus expertise:
 factors influencing distinct processing of faces,” Cognition,
This work was supported by Grants from Natural Science vol. 83, no. 1, pp. 1–29, 2002.
Foundation of Heilongjiang Province (LH2020H030) and [17] I. Gauthier, M. J. Tarr, A. W. Anderson, P. Skudlarski, and
Philosophy and Social Science Research Planning Project of J. C. Gore, “Activation of the middle fusiform ’face area’
Heilongjiang Province (19EDB091 and 16EDC03). increases with expertise in recognizing novel objects,” Nature
 Neuroscience, vol. 2, no. 6, pp. 568–573, 1999.
 [18] S. Brem, A. Lang-Dullenkopf, U. Maurer, P. Halder,
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