Impulsivity in patients with obsessive compulsive disorder and NIRS (Near infrared spectroscopy) imaging during cognitive performance

Objective: Although obsessive compulsive disorder (OCD) and impulse control disorders (ICD?s) have certain differences from each other, they share the dimension of impaired inhibition of intrusive, repetitive thoughts and behaviors. Both impulsivity and perfectionism dimensions -which is thought to be an opposite dimension to impulsivity- is frequently seen in OCD patients. The aim of this research is to investigate neuropsychological and electrophysiological effects of impulsivity and perfectionism dimensions in OCD patients on their cognitive - motor inhibition and attention mechanisms.Hypothesis: Our main hypothesis is that impulsivity and perfectionism scores of OCD group will be higher than healthy control group and accordingly the neuropsychological performance of OCD group will be lower and frontal cortex activity during tests will be higher than control group.Method: 32 patients, which consulted to Psychiatry Department of Dokuz Eylül University Hospital and 29 healthy controls matched them as age, gender and education level have attended to our research. All of the participants have been evaluated with Mini International Neuropsychiatric Interwiev (MINI), Yale-Brown Obsessive Compulsive Scale (Y_BOCS), Hamilton Rating Scale for Depression and Anxiety (HAM-D, HAM-A), Padua Inventory (PI), Multi-dimentional Perfectionism Scale (MPS), Barrat Impulsivity Scale (BIS) and on the Baloon Test. Blood flow changes occuring in frontal cortex of participants are recorded while they were performing the neuropsychological tests in which ?cognitive flexibility?, ?attention shifting? and ?motor inhibition? are measured and which activate especially prefrontal cortex, in brain biophysic research laboratory at Biophysic Department.Results: There were no significant difference between OCD patients and control group on Barrat Impulsivity Scale total score, motor impulsivity and nonplanning subscale scores of BIS and other-oriented perfectionism subscale scores of MPS. However, as expected, attentional impulsivity subscale scores of BIS, total Multi-dimentional Perfectionism Scale scores, and self-oriented and socially prescribed perfectionism subscales of MPS were higher in OCD patients than healthy controls. Nuropsychological results of this study have pointed out that both patient and control groups showed `right ear advantage? on dichotic listening tasks. Performance of OCD group was worse than control group on the last task of dichotic listening, which is designed to measure the ability of cognitive inhibition. In opposition to literature, motor inhibition scores of OCD patients were not worse than controls on go/nogo tasks. Finally, contrary to the hypothesis, electrophysiological findings have presented that OCD group didn?t showed hyperfrontality during these tasks. There were no significant difference between OCD and control groups on frontal cortex activity during the tasks.Conclusion: Along with the findings of this research we argued that OCD patients suffer from attentional impulsivity (Ettelt et al. 2007) and perfectionism at pathological levels (Lee et al. 2009). The suffering OCD patients clinically seemed that they were trying to control their urges all of the time and don?t trust their own perceptions. In addition, the severity of their compulsions increase with their perfectionism scores (Bhar and Kyrios 1999). Our findings support our hypothesis and the results of some further research (Westenberg, 2007; Ayçiçeği, 2003) showing that inhibitory functions of OCD patients are impaired. However it is still a matter of debate whether the problem is a cognitive or motor disinhibition. Our results represent that OCD patients suffer from a cognitive disinhibition rather than a motor disinhibition. Differentiation of inhibitory functions as `cognitive and motor? appears very important for the prognosis and rehabilitation of the disorder. Finally, suggested hypothesis about hyper- and hypofrontality in OCD and ICD patients (Hollander and Wong, 1995) haven?t been supported by the results of this research. First, the small sample size and secondly the fact that 75% of OCD patients were under anti-obsessive drug treatment could be reasons of this discrepancy.