The Impaction Of Insomnia On Spatial Memory And Object Recognition Memory

Background: Insomnia is a common physiological and psychological disorders, and can lead to impairment in social activities, interpersonal relationships and occupational mobilities. The incidence of insomnia is increasing with the enhancing social competition. Insomnia can be arosed either primarily or secondarily with other mental or physical illness. It is well known that insomnia can result in cognitive impairment, especially memory function. The spatial memory is the most common type of memory impairment in memory-impaired diseases. In the present study, a new experimental task was used to measure the spatial memory with more fitting characterization of the real environmental information.Objective: To observe the abilities of spatial and object recognition memories in the patients with primary and secondary insomnia, and to compare the action intensity of spatial memory in both insomnia and depression factors.Methods: Patients with primary insomnia (PI) and secondary insomnia (SI) which consist of major depression disorder (MDD) and dysthymia disorder (DD) were diagnosed according to DSM-Ⅳcriteria. The background information was collected. Following evaluation of the insomnia severity by Pittsburgh Sleep Quality Index (PSQI) and the depression severity by Hamilton Depression Rating Scale 17 (HAMD-17), their gross cognitive function was measured by Montreal Cognitive Assessment Scale (MoCA), spatial memory were measured by nine-boxes maze and object discriminational recognition memory was measured by picture recognition test. The patients assessment their memory by 0 (very poor), 1 (poor), 2 (moderate), 3 (good), and 4 (very good) grades. The data from the patients were compared with those from the control group.Results:①There was no significant difference among groups in sex, age and the years of education, but the total score of MoCA in the SI group was significant lower than that in the control group (P<0.05).②The total score of PSQI was higher in PI group than that in the SI group, and both were higher than that in the control group (P<0.001). The total score of HAMD was lower in the PI group than that in the SI group, and both were higher than that in the control group (P<0.001).③The spatial working memory was poorer in both the PI and SI groups compared to the control group (Ps<0.001), but there was no difference between PI and SI groups. Furthermore, the spatial working memory in the MDD group was significantly poorer than that in both the DD and control groups (Ps <0.05), but there was no significant difference between latter two groups. There was no significant difference among groups in object reference memory, object working memory and spatial reference memory.④The object discriminational recognition memory was significantly poorer in the SI group than that in the control group(P<0.001), but not in the PI group.⑤The memory self-assessment scores in both the PI and SI groups were lower than those in the control group (Ps<0.001).⑥A positive correlation occurred separatedly between the total score of either PSQI or HAMD17 and the errors of spatial working memory, a negtive correlation occurred separatedly between the total score of either PSQI or HAMD17 and the self-assessment score (Ps<0.05). Some factors of HAMD (anxiety/somatization, retardation and insight) and PSQI (sleep latency, sleep duration and sleep efficiency) were more correlated with spatial woking memory than others. Conclusion: The patients with PI and SI had decline of spatial working memory with significant contribution in both insomnia and depression but more in the latter. The object recognition memory impaired in load-dependent manner in the patients with SI. The impairment of memory can be sensated and percepted in the patients with PI and SI.