Response Discimination of Patients with Scizophernia and Bipolar Disorder in a Computer Generated Test of Auditory and Visual Attention Functioning
A previous study by Baerwald, Tryon, and Stanford (2005) examined response discrimination of patients with schizophrenia and bipolar disorder in a computer generated test of auditory and visual attention functioning (IVA). 95 patients out of 131 potential participants met the inclusionary criteria to participate in this study; no history of head injury, no history of schizoaffective disorder, scored “within normal limits” on the Mini-Mental Status Exam, and received a concordant diagnosis from the intake psychiatrists. 44 Patients with bipolar disorder and 51 patients with schizophrenia were contrasted to a “normal” comparison group in two conditions; simple modal responses, and ipsimodal or crossmodal responses. The simple modal condition presented auditory and visual stimuli in a random pattern in order to test the participants’ attention and impulsivity, while the ipsimodal and crossmodal conditions tested the participant’s attention during continuous and independent stimuli (i.e., auditory to auditory, visual to visual, or auditory to visual, visual to auditory.)
The results of this study suggest that in the simple modal condition, both the bipolar and schizophrenic subjects displayed different modal preferences however in opposite directions; the schizophrenic group showed a distinct visual over auditory preference, making a higher number of auditory commission errors, while the bipolar group showed an significant auditory over visual preference. In the ipsimodal and crossmodal conditions, all groups including the comparison group tended to make a higher number of errors in the auditory crossmodal condition (visual/auditory) in comparison with the other switching conditions. For this condition, the schizophrenic group has made more errors than any of the other groups although no significant medication effects were detected. In both of the conditions, the response sensitivity improved for all groups as the response bias became more neutral. This study proves that both patients with schizophrenia, and bipolar disorder are faced with attention disabilities, however there is a potential discriminator between the directions of modal response sensitivity within these two different disorders.
Impulsiveness is a trait which can be caused by many different factors; however studies which use experimental performance tasks of impulsiveness rarely consider that they might only evaluate small areas of this trait. In a study by Gorlyn, Keilp, Tryon, and Mann, a large number of similar performance tests were administered in order to find unique correlations between the sub-dimensions of impulsiveness. These sub-dimensions were assessed by the Barret Impulsiveness Scale (BIS), which is a scale used in order to measure impulsiveness. 42 English-fluent, well educated subjects were recruited to participate in this study with no history of psychiatric disorder, major medical illness, head trauma or abuse. However, two participants were subsequently dropped from the analysis considering they were both later found to have positive psychiatric histories. .
The participants were tested individually in a quiet designated testing room with a single examiner; the examiner remained in the room to ensure comprehension of the tasks. The first task was called the Time Production task which is a computerized version of a time estimation paradigm which measures cognitive tempo; fifteen trials were administered in total. In order to complete this task, the participants were asked to count in their heads the number of seconds indicated on the computer screen, and to press a key when that amount of time had passed. The computer then measured the time between the initial beep, and the participants’ pressing of the key. The participants’ performance on this task was measured as a percent deviation of their estimates from the actual length of the intervals. The next task which the participants needed to complete was called the Stop Signal test; the participants were required to discriminate between two letters presented on the computer screen, and press the appropriate button on the key pad. The participants were asked to respond quickly to the trials, but to withhold from responding to the trials that contained a tone. The final task which the participants needed to complete was the Complex Reaction Time task in which the participants were presented with 12 simple patterns of arrows (i.e. > > > < <), and 12 complex arrangements of arrows (i.e. < > > > <). The participants responded to these stimuli by using one of two keys to indicate the direction of the arrows of which they were presented. The participants were asked to respond quickly and accurately to each item, while the reaction scores for correct responses to the simple verses complex stimuli trials were computed. The results of the Time Production task showed that the mean estimates for each time interval were surprisingly very close to the actual amounts of elapsed time, while the reaction times for the Stop Signal task indicated that only 50 percent of the participants responded to the stop signal sound. The Complex Reaction Time task found that simple stimuli conditions had shorter reaction times than the complex stimuli conditions. Findings from this study indicate that multiple dimensions of impulsiveness can be assessed independently from one another.
A study done by Medalia, Aluma, Tryon, and Marriam in 1998 assessed the impact of attention training on information processing in patients with schizophrenia. Fifty four patients from the Bronx Psychiatric center between the ages of 20 and 45 years old were recruited to participate in this study. The subjects were split into two even groups based on their CPT ranking, and were assigned to either the experimental or control group; every six weeks a new group of subjects entered the training phase of the study. The CPT is a test which measures the severity of attention deficits. First, the subjects participated in a videotaped interview with an investigator in order to establish that the DSM-III-R criteria for schizophrenic patients were met; the DSM-III-R provides a common language and standard criteria for the classification of mental disorders. The participants were then administered a Quick test and a computerized version of the CPT; those who met the requirements for these two tests met with a clinician for twenty minute training sessions per week over a six week time period. The subsequent training sessions for the experimental group followed a uniform pattern. The first few minutes of training were spent taking a visual reaction time test from the ORM, a computerized training program, the next fifteen minutes were spent practicing various ORM attention/impulse training modules, and each session ended with another visual reaction time test. The ORM, or Orientation Remedial Module contains several modules: an attention reaction conditioner, zeroing accuracy conditioner, time estimates, and rhythm synchrony conditioner; all of these modules involve the receiving of auditory and visual stimuli.
Each module contains a test- train- test sequence where the test measures the participants’ reaction time. This “test-train-test” sequence was used in the experimental training sessions. The tasks in the ORM evoke arousal, alertness, rapid responsiveness, target detection, and information processing. The clinician was present during all sessions, and guided the subject through the tests without giving away answers. The training sessions for the control group were also very uniform in the sense that all subjects in the control group viewed the same, preselected National Geographic documentaries in the same order. While the participants were required to watch the videos, they were not required to discuss the videos, or otherwise indicate that they were actively processing them; the clinician was also present for all training sessions for the control group. After the six week intervention phase, the subjects participated in another videotaped interview, and were retested on the CPT. There were no significant group differences on the CPT measures at the start of the study; however the experimental group improved significantly more than the control group on the primary and secondary measures. The control group did not show any major changes in the CPT measures after the six week intervention period, while the scores in the experimental group changed significantly for the number of correct letter detections.
In the experimental group, impulse reaction time scores were measured at the start and end of each session; the scores declined significantly over the course of the 18 sessions. This study demonstrated the feasibility of using practice and behavioral learning to remediate a core attention deficit in schizophrenia. It was found that individuals receiving attention training made improvements on the reaction time and CPT measures, indicating that attention training has helped patients to become more vigilant and less distractible.
Baerwald, J. P., Tryon, W. W., & Sanford, J. (2005). Bimodal response sensitivity and bias in a test of sustained attention contrasting patients with schizophrenia and bipolar disorder to normal comparison group. Archives of Clinical Neuropsychology, 20, 17-32.*
Medalia, A., Aluma, M., Tryon, W., & Merriam, A. E. (1998). The effectiveness of attention training in schizophrenia. Schizophrenia Bulletin, 24, 147-152.*
Gorlyn, M., Keilp, J. G., Tryon, W. W., & Mann, J. J. (2005). Performance test correlates of component factors of impulsivity. Personality and Individual Differences, 38, 1549-1559.