حالت چهره و پردازش جهت گیری صورت در اسکیزوفرنی

Abstract Schizophrenia patients exhibit deficits in recognition and identification of facial emotional expressions, but it is unclear whether these deficits result from abnormal affective processing or an impaired ability to process complex visual stimuli such as faces. Participants comprised 16 outpatients with schizophrenia and 22 matched healthy control subjects who performed two computerized visual matching tasks (facial emotional expression and orientation). Accuracy and reaction time were recorded. Clinical symptoms were assessed in the patients using the Brief Psychiatric Rating Scale (BPRS), Scale for the Assessment of Positive Symptoms (SAPS), and Scale for the Assessment of Negative Symptoms (SANS). Social functioning as measured by the Zigler social competence scale was indexed in all participants. Patients with schizophrenia were less accurate than control participants on both facial emotion and orientation matching tasks, but there was no diagnosis-by-task interaction. Clinical symptoms of the patients were associated with deficits on emotion and orientation matching tasks. Worse social functioning was correlated with facial emotion matching errors across both groups. Patients with schizophrenia show general deficits in processing of faces, which is in turn associated with worse symptoms and reduced social functioning.

1. Introduction Past research indicates that both vocal and facial emotion recognition is impaired in schizophrenia (Walker et al., 1984, Feinberg et al., 1986, Borod et al., 1993, Archer et al., 1994, Mandal et al., 1998, Edwards et al., 2001, Baudouin et al., 2002 and Hooker and Park, 2002), and that this deficit is likely to be a trait-like feature of the illness (Kline et al., 1992, Schneider et al., 1995, Salem et al., 1996, Poole et al., 2000, Exner et al., 2004 and Addington et al., 2008). Schizophrenia patients (SZ) perform worse than healthy control subjects (CO) on tasks that require emotion identification or discrimination (Walker et al., 1980 and Salem et al., 1996), but such deficits may stem from a generalized deficit in face processing. Indeed, evidence suggests that there is no specific deficit in emotion perception in schizophrenia (Kerr and Neale, 1993) but that they may have generalized deficits in processing of faces (Salem et al., 1996) and face processing deficits may be related to cognitive deficits in schizophrenia (Schneider et al., 1995, Bryson et al., 1997, Addington and Addington, 1998 and Kohler et al., 2000). The relationships among symptom severity, emotion processing, and face processing have been investigated but are not clearly understood. Some studies have found a relationship between increased positive symptoms and deficits in face processing (Schneider et al., 1995, Kohler et al., 2000, Baudouin et al., 2002 and Martin et al., 2005); other studies have found a relationship between negative symptoms and deficits in face processing (Mueser et al., 1996, Kohler et al., 2000 and Suslow et al., 2003b), and yet other studies have found no relationship between symptoms and face processing (Muzekari and Bates, 1977, Borod et al., 1993 and Salem et al., 1996). Nevertheless, accurate processing of socially relevant stimuli such as faces seems to have important implications for social functioning in schizophrenia (Hooker and Park, 2002, Suslow et al., 2003a and Kim et al., 2005). The goal of the present study was to extend previous findings of facial processing deficits of schizophrenia in relation to social functions using two simple matching tasks with no language or memory demands, which may introduce additional cognitive load. We hypothesize that SZ subjects will be impaired on both the emotion matching task and the orientation matching task compared with CO subjects. We further examined reaction time performance on these tasks in order to gauge whether or not there was additional cognitive loading.

Results 3.1. Accuracy There was a main effect of diagnosis (F(1,36) = 10.10; P = 0.003, r = 0.89). CO subjects (Mean = 92.50%; S.D. = 8.46) performed better overall than SZ subjects (Mean = 81.41%; S.D. = 20.25). A main effect for task was also found (F(1,36) = 8.82; P = 0.005, r = 0.84). Subjects performed better on the facial orientation task (Mean = 92.50%; S.D. = 18.45) than on the emotion matching task (Mean = 83.16%; S.D. = 10.16). There was no significant interaction (see Fig. 3). Accuracy on the matching tasks. Mean percent correct (S.E.). Fig. 3. Accuracy on the matching tasks. Mean percent correct (S.E.). Figure options Given the uneven ratio of male to females in the study, it is important to address potential sex differences. A multifactorial ANOVA with diagnosis and sex as independent variables was conducted on the accuracy of the performance on the two face tasks. There was no main effect of diagnosis or sex. There was no diagnosis-by-sex interaction. 3.2. Reaction time There was no main effect of diagnosis (F(1,36) = 0.22; P = n.s.), but there was a main effect of task type (F(1,36) = 20.09; P < 0.0001, r = 0.99). Subjects were faster on the face-orientation task (Mean = 4723 ms; S.D. = 3516) than on the emotion matching task (Mean = 7153 ms; S.D. = 2326). There was a trend towards a group-by-task interaction (F(1,36) = 4.03, P < 0.06, r = 0.49). However, post-hoc analyses showed no significant differences in reaction time between groups on either the facial orientation matching task or the emotion matching task (see Fig. 4). Response times of matching tasks. RT in milliseconds (S.E.). Fig. 4. Response times of matching tasks. RT in milliseconds (S.E.). Figure options 3.3. Relationships with social functioning and symptomatology There was a significant group difference on the Zigler score of social functioning (F(1,36) = 26.59, P < 0.0001), with the CO subjects scoring higher than the SZ subjects. Across both groups, the Zigler score was positively correlated with the performance on the emotion matching task (r = 0.38; P = 0.02). Interestingly, there was also a trend for a significant correlation between the Zigler score of social functioning and performance on the face-orientation task (r = 0.31, P = 0.06) suggesting that better performance on face processing in general may be related to better social functioning. In the SZ group, BPRS ratings were negatively correlated with performance on the emotion matching task (r = − 0.57, P = 0.02), suggesting that SZ subjects with ia high level of symptoms were less accurate on the emotion matching task. There was a significant negative correlation between positive symptoms (SAPS) and accuracy on the emotion matching task (r = − 0.54, P = 0.04). There were no significant correlations with negative symptoms and task performance. Illness duration was negatively correlated with performance on the face-orientation task (r = − 0.68, P = 0.07) and positively correlated with RT on the same task (r = 0.74, P = 0.04). Daily medication dose (as measured by the CPZ equivalent) was positively correlated with performance on the face-orientation task (r = 0.53, P = 0.05) and negatively correlated with reaction time on the same task (r = − 0.60, P = 0.02). These findings suggest that symptom management is related to the ability to process facial stimuli. In other words, those patients with better face processing ability tend to have fewer symptoms.