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Comparison of the diagnostic and selective reaction time in schizophrenic patients and normal people at Andimeshk city.

INTRODUCTION

Schizophrenia is a disorder with symptoms that numerous inconsistencies in the content of thought, perception, emotion, understanding, motivation, behavior and interpersonal functions [3]. It is a complex mental disorder that has the strongest and most damaging effect on peoples' life [2]. In DSM5, its symptoms are delusions and hallucinations, disorganized speech and negative symptoms [6]. For those who work with people with schizophrenia, attention deficit has always been considered. That's why it seems that the information they receive from their environment is different from the ones received by the others [1]. Since many of schizophrenia have described their perceptions are clearly more unrealistic than usual, the size and shape of objects may seem unusual to them. Some of schizophrenia do not show a good performance on tests of attention, for example, signal detection in noisy background. To date, we have tried that these deficits are explained in terms of current models of information transfer in the nervous system that have not helped knowledge advancement regarding the etiology of schizophrenia. In general, it seems that schizophrenia cannot selectively focus on important aspects of sensory input. [5]. Specialists propose methods in the treatment of schizophrenia that targeted the complex and sensitive aspects of the patient's understanding. Several institutions have prioritizes improvement and growth of cognition schizophrenia for treatment and nervous-psychological laboratories conduct the cognition process in these patients with more seriousness [18]. Studying cognitive injuries by the tests showed that these injuries is the main core of schizophrenia that includes difficulties in working memory, executive function and attention [15]. Cognitive impairments have complex relationship with schizophrenia clinical syndrome, including impaired thinking, impaired vision, and disability [23]. Brain circuitry findings tape recorded some changes in the attention and active memory of schizophrenia patients [17]. Schizophrenia patients are affected with serious injuries in a large functional areas such as social skills and social cognition. These social injuries include problems such as perception, understanding, participation in social activities and reaction to the clues that are essential for the social interactions [13]. Therefore, in this study we sought to measure reaction time. Reaction time is the time it takes a person to voluntarily respond to more or less complex stimuli. Since the reaction time is used as a test of accuracy and consistency, its measurement is needed in most experiments. The reaction time depends on the following factors: A - the time of sensory receptors stimulation, B - the time of stimulation transfer to the central nervous system. C - The time of central nervous system reaction and giving the reaction order. D- The time of command transfer from central nervous system to respondent members and then reaction by respondent members. Also, the man responds to external stimuli in two ways: voluntary and involuntary. Voluntary reactions are those made with the knowledge and volition. The person has no knowledge in involuntary reactions.

Research results have shown that schizophrenia patients spend more time to respond to light and sound stimuli than those in normal people and their simple reaction time, selective reaction time and detective reaction time is slower than the normal people. Due to emotional, affection and depressed mood which causes ability and function disorder, schizophrenic patients cannot give a rapid reaction to light and sound stimuli [7]. By reviewing the studies and research carried out and results achieved in the fields of psychology that will investigate in the present study, undeniable importance and role of attention and concentration in reaction to environmental cues is determined. Hence, Iranian psychologists need to pay attention to this issue and conduct a scientific review of the impacts of attention and concentration on reaction time. In the study conducted by Nikpour and Homayouni [7] in connection with the reaction time in schizophrenic patients and normal people, results showed that there was no significant difference between the mean scores of the two group i.e. schizophrenic patients spend more time to respond to light and sound stimuli than the control group and concluded that schizophrenia patients are unable to give a rapid reaction to sound and light stimuli due to emotional and affective disorders and depressed mood that causes disorder in their ability and performance. In the study conducted in Tehran University of Physical Education aiming to investigate the impacts of determining objective in the time of selective reaction on 50 male athletic students, Gholami [4] concluded that objective determination can be led to improving selective reaction among which determining a difficult objective is more effective than other methods and personal goal is in the next place and finally a simple goal is effective on the time of selective reaction. In the study conducted by Douglas, Berger, Nezo, Shinnichi, Iga, Tomie, Hosaka, Takashi, Nakamura and Seiro [19] on schizophrenic patients and normal persons by Electrogram, two results were found after measuring mutation reaction speed: A: there is a reaction shortage to information processing in schizophrenic patients. B: this reaction shortage may be useful in confirmation of the presence of schizophrenia in older age groups. In another study by Theodore and Zan took place in Berlin, Germany, they also concluded that reaction time and focus on people with schizophrenia is clearly lower than the normal people.

Howard, Gale, Philip and Holzman conducted a study on schizophrenic patients at Harvard University and 28 normal subjects were performed to measure the reaction rate.

This reaction time was presented as 2 stimuli (tactile as well as visual) and three stimuli tactile + auditory + visual). In another study in 1999-2000, Spring measured attention maintenance using reaction measurement between 2 groups of patients, i.e., bipolar patients and schizophrenic patients and normal subjects. The number of patients in each group were 20 patients. The results show that the reaction rate in schizophrenic patients is slower than in normal individuals and bipolar patients and as a result their power to maintain attention is lower than that of normal subjects and bipolar patients. Also, in the study done by Payne and Hochberg (2006), reaction time is affected by irritating stimuli in schizophrenia and normal men were measured. The results of this experiment indicate that this motivational factor as irritating stimuli influence people with schizophrenia than the reaction time among normal people. Rubin and Stein [22] conducted a study in which a simple reaction time in patients with schizophrenia and affective disorder patients were compared and measured. The results of this study indicate that simple reaction rates are slower than those of schizophrenic patients who are suffering from emotional disorders. In another research conducted by Skodol, Buckley, Salamon, the relationship between negative symptoms of schizophrenia and the reaction rate was studied. The results of this study show that negative symptoms in schizophrenia are associated with the speed of reaction and the more the symptoms in patients, reaction rate will be lower.

Chapman and Lawson [12] conducted a study in which reaction time of 11 schizophrenic patients and 11 normal subjects after a series of regular pre-fitness was measured in which the research results confirms the slower reaction rate in schizophrenic people than the normal ones despite a pre-fitness period. In a study conducted by Nuechterlein and Keith [19], reaction rate and focus in schizophrenic patients were examined and measured. The results of these study confirmed the slow performance (reaction rate) and a lack of sufficient attention and concentration and they attribute the main reason equally to both genetic and environmental factors.

In 2002, Bojan Zalar, Martina Tomori and Ivan Krajnc conducted a study that measured the simple reaction rate in patients with schizophrenia before and after treatment with antipsychotics. The result of the study was that schizophrenic reaction rate before treatment were significantly longer than control group i.e. those in normal people. However, it was significantly improved after 8 weeks of treatment in patients. Also, in a study conducted by Spring and Zoubin [24], reaction rate in 45 patients with schizophrenia and 68 normal people as control group were measured. The research results show that reaction rate of schizophrenic patients was lower than that of normal people. Also, the ability to maintain attention and concentration are significantly lower than the control group. Rijesdijk and Vernon [21] examined influential factors of reaction time, including age, body size, intelligence, etc. The results of the research on the relationship between reaction time and intelligence indicated that there is a significant correlation between IQ and reaction time. Buckhalt [10] conducted a study regarding the relationship between intelligence, reaction time and movement time in three different tasks on 41 adult students. The results showed that none of the movement time measurements in three different tasks have a significant relationship with intelligence. In this study, we answer the question whether there is a difference between detective reaction time and selective reaction time in patients with schizophrenia and normal people.

The hypothesis of the study include:

1. The selective and detective reaction time in normal women is more rapid than female patients with schizophrenia.

2. The selective and detective reaction time is more rapid than that of normal males with schizophrenia.

Methodology:

This is a comparative-causal study. Statistical population included all mental patients under the Welfare in Andimeshk city and all healthy people in this city. This study is composed of two experiment and control groups. The experimental group consisted of patients under support at Mahtab Center in Andimeshk which all patients were selected as a sample. And the control group consisted of healthy subjects who were selected as available sampling. The sample consisted of 40 male schizophrenic patients and 40 female patients with schizophrenia, 40 normal male and 40 normal female subjects. In order to gather the necessary data, a reaction measurement device (chronoscope) has been used. Chronoscope is an instrument that can both measure the rate of reaction and also have sporadic precision for the reaction time of a physiological limit. This limit is 12hundredths of a second. To measure the reaction time, two steps of detective and selective reaction rate was reviewed, so that two light driver is selected, for example, red and light and a green button that a subject choose will indicate to him/her e.g. if one sees a red light, one might press the button and if one sees the green button, one may not press the button. In this condition, subjects error is also considered (30 red ones should be presented). Of the total number that is provided, if the number of subject's' errors is at least 5, it indicates one's passivity. The type of driver sill be told to the subject in the selective reaction rate and the button is provided to the subject. For example, if one sees the red button, press the right hand and if one sees the green light, press the left button (50 is presented randomly with red and green stimuli). The experiment secretary should rapidly take note the time in each experiment. After determining the sample group (160 subjects), reaction device will be provided to the individual subjects after explaining about the method by it for the subjects, ach reaction time is done with selective method, MANOVA analysis method and T test as well as using SPSS software. Significance level for all hypotheses is considered 0.05.

Findings:

As the results in Table 1 show, a significant difference was observed in the mean normal men and schizophrenic men in diagnosed reaction component (34.46 vs. 56.05), i.e. normal men have better detective reaction power than that of schizophrenic men. Also, a significant difference can be observed in the mean of normal men and schizophrenic men in selective reaction component (77.71 vs. 104.23), i.e. normal men have better selective reaction power than that of schizophrenic men.

As the results in Table 2 show, a significant difference was observed in the mean normal women and schizophrenic women in diagnosed reaction component (41.47 vs. 48.80), i.e. normal women have better detective reaction power than that of schizophrenic women Also, no significant difference could be observed in the mean of normal women and schizophrenic women in selective reaction component (95.56 vs. 91.28), i.e. normal women have almost the same selective reaction power with that of schizophrenic women.

Hypothesis 1: There is a difference between selective reaction time and detective reaction in schizophrenic and normal men.

As can be observed in Table 3, significant levels in all tests indicate that mean tests in terms of selective reaction time, detective reaction in the of schizophrenia patients and to review more difference in mean scores of selective reaction time, detective reaction in male patients with schizophrenia and normal men one-way ANOVA test was used that has been reported in Table 3.

F-value of diagnostic reaction times equals (P < 0.001 and F=89.834) which indicates that the difference between the two groups of schizophrenic and normal patients at P < 0.05 level is significant that this difference is in favor of schizophrenic men, i.e. normal men have better detective power than schizophrenic men. It is concluded that detective reaction time in normal men is more rapid than schizophrenic male patients. Also, F-value of selective reaction equals F=15.662 and P < 0.001) which shows that the difference between the two groups of schizophrenic and normal patients at levels p < 0.05 level is significant that this difference is in favor of schizophrenic men, i.e. the normal male have more selective reaction time than potency schizophrenic men. It is concluded that selective reaction time in normal men is more rapid than schizophrenic men, then the hypothesis 1 is confirmed.

Hypothesis 2: there is a difference between selective reaction time and detective reaction in normal and schizophrenic female patients.

As can be observed in Table 4, significant levels in all tests indicate that mean tests in terms of selective reaction time, detective reaction in the female schizophrenia patients has a significant difference. It is worth mentioning that Wilkin's lambda with selective and detective reaction among normal and schizophrenic women is shown in 0.05 significance level. To evaluate more difference between the selective reaction time and detective reaction time among normal and schizophrenic patients, MANOVA test has been used which has been reported in Table 5.

F-value of diagnostic reaction times equals (P < 0.004 and F=8.924) which indicates that the difference between the two groups of schizophrenic and normal patients at P < 0.05 level is significant that this difference is in favor of schizophrenic women, i.e. normal women have better detective power than schizophrenic women. It is concluded that detective reaction time in normal women is more rapid than schizophrenic female patients. Also, F-value of selective reaction equals F=0.432 and P < 0.06) which shows that the difference between the two groups of schizophrenic and normal women at levels p < 0.05 level is not significant, i.e. normal women have almost the same section reaction time that of schizophrenic women. It is concluded that selective reaction time in normal women is not more rapid than schizophrenic women, then the hypothesis 1 is confirmed.

Discussion and Conclusion:

According to the results of this study and research conducted, it seems that the core of thought disorder in schizophrenics is the inability is withdrawal of irrelevant stimuli which most of us can selectively focus on our problems. We can choose stimulus in relation to the duty that we have at hand and ignore other stimuli among the mass of sensory information that we receive. A person with schizophrenia is not apparently leave aside irrelevant stimuli or detect data among relevant ones. In addition, these patients may realize that their concentration on stimuli has been reduced and cause further delay in reaction time. However, the distribution of reactions according to previous studies (Hilgard) indicates that getting used to stimuli in people in this organization has a certain preparation due to stress. According to cognitive theory, this physiological variation caused by what is mentioned above is combined with double effects of mental stressful situations and is led to unusual attention process, as was observed in results. Since the measurement of feeling, not only measures the sensitivity of the subject but also his way of making decision, it seems that late reaction to colors by schizophrenic patients is due to their affective and emotional disorders. The findings showed that selective reaction time in normal men is more rapid than that of male schizophrenic patients (F=662.15, P < 0.001) and there is a significant difference between them which confirmed the first hypothesis of the study. The study conducted by Spring and Zobin in 1994 and Chapman and Lawsen in 2007 showed that selective reaction time in normal men is more rapid than male schizophrenic patients. Also, the results showed that detective reaction time in normal men is more rapid than male schizophrenic patients (F=834.89) & P < 0.001) and there is a significant difference between them. In the study by David Shakof and David Rosenthal conducted in 8119, it was found that detective reaction time in normal men is more rapid than male schizophrenic patients. Also in this study, manual or performance and verbal reaction time in schizophrenic patients was compared with that of normal subjects. The results of this study slow the slowness of reaction time in schizophrenia patients compared to normal subjects. It was also concluded that the slowness of reaction time is related to cases such as reinforced type, amount of exercise, verbal reaction complexity and degree of patient's injury. Research findings show that there is no significant difference between normal women and female schizophrenic patients in terms of selective reaction time (F=0.832 and P < 0.001). Thus, our hypothesis was not confirmed in selective reaction time and this was inconsistent with the results of research obtained by Theodore Vazan in 1977, David Shakof and Rosenthal in 1981 and Spring and Zobin in1994. In addition, comparison of the mean selective reaction time in normal men with normal women shows that selective reaction time in normal men is more rapid than normal women; on the contrary among patients with schizophrenia, selective reaction time in schizophrenic men is slower than schizophrenic women. Also, results analysis showed that detective reaction time in normal women is more rapid than that of schizophrenic women (F=924.8 and P < 0.001) and there is a significant difference between them, which Pin and Houchburg in 2006 and Newchetralin and Kide in 2001 obtained similar results that detective reaction time in normal women is more rapid than female with schizophrenic patients. Furthermore, comparison of the mean detective reaction time of normal men with normal females shows that detective reaction time in normal men is faster than normal women, but this was reversed in the case of schizophrenic patients; i.e. detective reaction time in men was slower than that of women with schizophrenia. Briefly summarizing the findings of this study showed that:

There is a significant difference between normal men and male schizophrenic patients in terms of selective reaction time. There is a significant difference between normal men and male patients with schizophrenia in terms of detective reaction time. There is no significant difference between normal women and female patients with schizophrenia in terms of selective reaction time. There is a significant difference between normal women and female patients with schizophrenia in terms of detective reaction time.

ARTICLE INFO

Article history:

Received 11 June 2014

Received in revised form 21 August 2014

Accepted 25 September 2014

Available online 25 November 2014

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(1) Farzaneh Golshekoh and (2) Parnian Pasha

(1) Department of Humanities, College of Psychology, Andimeshk Branch, Islamic Azad University Andimeshk,, Iran

(2) Farhangian University, Pardis Fatemah Alzahra Branch, Ahvaz, Iran

Corresponding Author: Farzaneh Golshekoh, Department of Humanities, College of Psychology, Andimeshk Branch, Islamic Azad University Andimeshk,, Iran
Table 1: Central and dispersion indices in detective and selective
reaction components among normal and schizophrenic men.

Group                  number       Descriptive statistics indices

                                 Mean     SD    Minimum   Maximum
                                                 score     score

The normal component     40     34/46    5/05    25/30     44/06
of the diagnostic
reaction in men

Schizophrenia of         40     56/05    13/4    19/78     75/50
detective reaction
component in men

Normal in selective      40     77/71    11/6    49/30    111/82
reaction component
in men

Schizophrenia in         40     104/23   40/7    4/48     151/90
selective reaction
components among men

Table 2: Central and distributional indices in selective and
detective reaction component among normal and schizophrenic women.

Group                  number      Descriptive statistics indices

                                Mean     SD    Minimum   Maximum
                                                score     score

The normal component     40     41/47   4/4     29/10     51/86
of the diagnostic
reaction in women

Schizophrenia of         40     44/80   14/8    8/03      72/30
detective reaction
component in women

Normal in selective      40     95/56   16/1    46/68    140/64
reaction component
in women

Schizophrenia in         40     91/28   37/9    11/45    144/88
selective reaction
components among men

Table 3: Results of multivariate analysis of variance (MANOVA) in
scores of selective reaction time and detective reaction time in
schizophrenic and normal men.

Test name               value   F test    Hypothesis
                                          degree of
                                           freedom

Pillai's trace test     .844    136.769     3.000
WILKS' Lambda test      .156    136.769     3.000
Melting trace test      5.399   136.769     3.000
The biggest root test   5.399   136.769     3.000

Test name               Hypothesis   Significance
                        degree of       level
                          error

Pillai's trace test       76.000        0.001
WILKS' Lambda test        76.000        0.001
Melting trace test        76.000        0.001
The biggest root test     76.000        0.001

Table 4: Results of the MANOVA on selective reaction time and
detective reaction time in schizophrenic and normal men patients.

Source of changes    Degree of   F test   Significance
                      freedom                level

Detective reaction       1       89.834      0.001
Selective reaction       1       15.662      0.001

Table 4: Results of the MANOVA on selective reaction time and
detective reaction time in schizophrenic and normal female patients.

Test name               value   F test   Hypothesis
                                         degree of
                                          freedom

Pillai's trace test     .621    41.546     3.000
WILKS' Lambda test      .379    41.546     3.000
Melting trace test      1.640   41.546     3.000
The biggest root test   1.640   41.546     3.000

Test name               Hypothesis   Significance
                        degree of       level
                          error

Pillai's trace test       76.000        0.001
WILKS' Lambda test        76.000        0.001
Melting trace test        76.000        0.001
The biggest root test     76.000        0.001

Table 5: Results MANOVA analysis on selective reaction time and
detective reaction time scores among normal and schizophrenic female
patients.

Source of changes    Degree of   F test   Significance
                      freedom                level

Detective reaction       1       8.924       0.004
Selective reaction       1        .432        0.6
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Author:Golshekoh, Farzaneh; Pasha, Parnian
Publication:Advances in Environmental Biology
Article Type:Report
Geographic Code:7IRAN
Date:Nov 15, 2014
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