الفهرس 
Introduction
OCD: A Historical viewOnly 14 pages are availabe for public view
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Abstract
Obsessive-compulsive disorder (OCD) is a chronic and disabling disorder marked by obsessions and/ or compulsions; it causes significant distress to the patients and their families. (Iancu et al., 2003)
Despite recent developments in drug and behavioral treatments of OCD, about 40%–60% of cases remain refractory to treatment.(Pallanti et al., 2002)
lRecent neurophysiologic and neuroimaging studies suggest that premotor and motor areas are hyperactive in OCD.(Ziemann et al., 1997; Greenberg et al., 2000; Margaret et al., 2012)
TMS can be used to measure various parameters in motor cortex allowing us to evaluate different aspects of cortical excitability.(Hallet et al., 1999)
With use of rTMS, it has become possible to modulate local neuralactivity by inducing a depolarizing magnetic field pulse.(Barker et al., 1985)
Because OCD may be related to increased neural activity inprefrontal subcortical circuits the inhibitory effect ofrTMS was hypothesized to be beneficial in OCD treatment.(Whiteside et al., 2004)
By now, there is evidence that rTMS treatment could improve OCD and the effect persists up to 3 months.(Mantovani et al., 2006; Ruffini et al., 2009)
The aims of the present study are:
1- Assess the cortical excitability in patients with OCD in order to understand more about its pathophysiological mechanisms.
2- Evaluate the therapeutic impact of different frequencies of repetitive transcranial stimulation (1HZ, 10HZ) in OCD patients.
Subjects and methods:
Forty five patients participated in the study. The patients were selected consecutively from those attended the Psychiatry unit at the department of Psychiatry and Neurology, Assiut University Hospital, Assiut, Egypt.They were diagnosed as having OCD based on DSM-IV-TR.(Kaplan& Sadock 2007)
The age matched control group consists of fifteen healthy volunteers. They had no history of psychiatric disorders.
All patients were assessed with the following:
• Neurophysiological assessment
• Psychological assessment
The neurophysiological assessment:
For patients as well as the normal volunteers;cortical excitability was studied by measurement of the resting and active motor threshold, cortical silent period, trancallosal inhibition and intracortical facilitation and inhibition.
The psychological assessment:
Before rTMS (pre) and immediately after the end of sessions and after 3 months patients evaluated by:
1- Yale Brown obsessive compulsive scale (Y-BOCS).
2- Hamilton anxiety rating scale (HAM-A).
3- Clinical global impression-severity scale (CGI-S).
Repetitive transcranial magnetic stimulation:
The rTMS was applied with its center placed over the optimal position for the right DLPFC where 2000 pulse where applied.
The patients were randomly classified into three groups:
1st group was 15 patients received 1 Hz rTMS with intensity of 100% of the RMT applied in 200 trains, each of 10 pulses, with 5 seconds intertrain interval.
2nd group was 15 patients received 10 Hz rTMS with intensity of 100% of the RMT applied in 10 trains, each of 200 pulses, with 45 seconds intertrain interval.
3rd are sham group of 15 patients received the same number of pulses 2000 pulse applied in 200 trains, each of 10 pulses, with 5 seconds intertrain interval. The coil was placed over the same area but perpendicular to the scalp.
The patients didn’t know whether they are receiving real or sham rTMS.
Results of the study:
Neurophysiological:
There was significant lower RMT and AMT in OCD patients compared with control group. Also CSP and TCI were significantly decreased in OCD patients which support the presence of cortical hyperexcitability in OCD patients. Another finding that is in line with the previous finding is that ICF is increased in OCD patients. Also OCD patients have decreased ICI in comparison to control group.
Therapeutic effect of rTMS:
Compared to sham stimulation, 1Hz rTMS over right DLPFC improved all measures(Y-BOCS, HAM-A, CGI-S).The effect maintained for 3 months after.
However there was significant improvement after application of 10Hz rTMS over right DLPFC immediately after sessions in comparison to sham stimulation this effect doesn’t maintained for 3 months.