The Study Of Working Memory And ~1H Magnetic Resonance Spectroscopy Imaging In Untreated Patients With Obsessive-compulsive Disorder

Objective:Adopting 1H Magnetic Resonance Spectroscopy(1H-MRS) and neuropsychological tests to examine working memory capacity of drug-na?ve obsessive-compulsive disorder(OCD) patients, explore the relationship between working memory and levels of cerebral metabolism at the same time, so that we can provide the basis for phenomenology, early identification as same as intervention of OCD. Methods:There are 63 first-episode obsessive-compulsive disorder patients and 58 healthy collators have performed 4 working memory tasks, including digital span, 2-back, spatial memory and Stroop color and word test. These two groups were also evaluated by the levels of N-acetylasparte(NAA), choline compounds(Cho), and creatine(Cr) through 1H-MRS at the frontal lobe and bilaterally lenticular nucleus. We analyzed the correlation of working memory and levels of cerebral metabolism as well. Results:(1) The patients group was significantly lower in the score of 3 digital span tests. The accurate answer score in 2-back task was lower than that in normal control. The patients group also had lower score in visual space memory test. Completion time of Stroop-CW test and visual space memory test was longer than that of normal control. As for the completion time of 2-back task and Stroop-C test, we did not find any significant difference between patients group and healthy collators.(2) The patients group had a remarkably increased NAA/Cr ratio in the left frontal lobe, and there were not any significant results in the ratios of other areas between two groups.(3) In the OCD group, the 2-back task(time) was negatively correlated with NAA/Cr ratio in the left frontal lobe; the digital span tests(backward, total score) had a positive correlation with education, but the Stroop-C test(time) and the Stroop-CW test(time) both were negatively correlated with it. Meanwhile, the Stroop-C test(time) had a positive correlation with the course of the disease. The NAA/Cr ratio in the right lenticular nucleus of patients group was positively correlated with Y-BOCS. Conclusion:(1) Drug-na?ve OCD patients have working memory impairments indeed, which including phonological loop, visual-spatial sketchpad and central executive system.(2) The metabolism of NAA in the left frontal lobe in drug-na?ve OCD patients was dysfunction, and their verbal working memory impairments may be related to the abnormal membrane phospholipids in the frontal lobe as well.(3) The lower education level of drug-na?ve OCD patients had, the more serious their memory, attention and inhibition function might get impaired; while the aggravation of symptoms might relate to the neuronal dysfunction in the right lenticular nucleus.