| Objective Alexithymia maybe one of features in Schizophrenia patients. Some etiological models of alexithymia proposed the dysfunctions of right cerebral hemisphere, prefrontal cortex and corpus callosum. In neuropsychology, the term executive functions has long been used as a synonym for frontal lobe function, implying a parallel of the functional and the anatomical .We proposed a dysfunction of the neuromechanism to account for the characteristic pattern of alexithymia by taking neuropsychological tests. This study aims to investigate (1) whether excutive function is damaged in people with alexithymia and (2) whether the prefrontal cortex is involved in the special network of alexithymia,if alexithymics manifest a deficit in executive function.Methods Five hundred students from Anhui medical university were screened in small groups for levels of alexithymia, using the Toronto Alexithymia Scale (TAS-20). Alexithymic group included 33 students over 60 scores(15 male and 18 female) and control group included 30 students (16 male and 14 female). The following exclusion criteria were also fulfilled by all participates: (a) no demonstrable brain disease (i.e. no loss of consciousness nor any history of neurological conditions such as epilepsy, schizophrenia, brain injury, or head trauma); (b) no history of depressive disorder, anxiety disorders; and (c) no evidence of current substance (including alcohol) abuse. The functioning of prefrontal lobe was measured by the attention network test (ANT), the Stroop test , digital span test and digital sign test . We wanted to find whether that high alexithymics performed significantly difference in all tasks than normal controls.Results The alexithymic group had similar overall RT (t(63)=0.532, p =0.601),and accuracy (t(63)=0.345 p=0.738,) to the control group. The data showed that patients took longer to resolve conflict (t(63)=2.568, p=0.01). The differences between groups for alerting and orienting network scores were not significant (t(63)=-0.42, t(63)=1.448, p =0.155). Since RTs are generally longer in patients, it is useful to use the ratio to examine specific effects that are not influenced by overall reaction time. In addition to the significant difference on conflict resolution (t (63) = 2.80, p<0.01) . Comparing the alexithymics and control groups, the difference based on ratio score of alerting effect was not significant. In stroop test,there were no significant difference between groups on the number of items completed under the colour condition (t = -0.87, p>0.05) or the colour-word condition (t =0.34, p>0.05). Tests showed that the alexithymics experienced greater interference as indicated by their interference total score (t = 2.83, p < 0.01), they made a smaller proportion of errors (t = -0.09, p<0.05) and were significantly slowed in completing the interference task. Particularly,there was a significant difference between the two groups in stroop effect(t =3.75, p < 0.001). The differences between groups for digital span test and digital sgin test scores were significant (t=-2.81,p =0.008; t=-4.71,p<0.001; t=-2.26,p<0.05). The correlation between the executive network and two of the Stroop test subscale scores (interference condition and stroop effect) was not significant (interference condition r = -0.089, p's<0.05; stroop effect r = 0.14, p's > 0.05).Conclusions The results confirmed that alexithymics manifest a deficit in executive function impaired abilities of executive function were important reason for the impairments of s prefrontal cortex . The study also supported that impaired executive function in alexithymics was probably correlation with the abnormalities of prefrontal cortex. |
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