Changes Of Procedural Memory In The Patients With Pirmary Insomnia

Background Previous studies showed that chronic insomnia patients had extensivecognitive impairments, mainly presented as poor alertness, memory, executive function,and motion control. And the learning-memory difficulty was the most common one.However, whether the patients with primary insomnia （Primary insomnia, PI） havethe memory damage is still unknown. Procedural memory （Procedural memory, PM） isthe phenomenon that the current task affected by the past experiences spontaneouslywithout awareness or recall on purpose. It is one of the most important cognitivefunctions in human. It contains priming effects and skill learning. Because of thedefects of non-PI patients, memory means of detection uniformity and other defects,there is no conclusion on the damage of PM in the PI patients.Objective The aim of this study is to certify whether PI patients have the impairmentsin PM and characters of it. Meanwhile, we observe the changes of Declarative memory（Declarative memory, DM）.Methods36PI patients and36controls were enrolled in this study according to theDSM-IV diagnostic criteria. The PI patients were divided into three sub-groups, i.e.difficulty initiating sleep （DIS）, early morning awakening （EMA） and difficultymaintaining sleep （DMS）. Background information of all subjects were collected, andAthens Insomnia Scale （AIS）, Epworth Sleepiness Scale （ESS）, Hamilton DepressionRating Scale （HMAD-17） and Montreal Cognitive Assessment Scale （MoCA） wereused to assess the quality of sleep, the degree of sleepiness, the severity of depressionand the overall cognitive function, respectively. The PM were examined through thepriming effect to produce experimental and skills learning exercise sequence detection task, and the DM were detected through the immediate recall, delayed recall and delayrecognition task.Results①the results according to the U or t-test showed that there were nostatistical differences of gender, age and education levels between PI and control group.The MoCA （z=1.710, P=0.087） and ESS （t=1.237, P=0.220） of the two groupsshowed no significant differences, but the AIS and HAMD₁₇were significantly higherin the PI group than those in the control group （z=7.430, P <0.001；z=7.083, P<0.001）.②the results of U test showed that the immediate recall （z=6.479, P<0.001）, delayed recall （z=4.747, P <0.001）, delay recognition （z=4.637, P <0.001）,categories and （z=5.537, P <0.001） and the movement sequence （z=4.152, P<0.001） of the PI group were significantly worse than those of the control group.③in the further study on different subtypes of sleep difficulties, the results ofsingle-factor analysis of variance or H-test showed that there were significant or at lestmarginal differences of the delayed recall （F=3.264, P=0.051）, delay recognition（H=8.871, P=0.012） and the movement sequence （H=9.766, P=0.008） amongDIS, EMA and DMS, while there were no significant differences of immediate recall（H=0.840, P=0.657） and type of produce （H=0.399, P=0.819） among them. Aftercomparing between each subtype, the results showed that delayed recall （Ps=0.025and0.05）, delay recognition （Ps=0.031and0.007） and movement sequences （Ps=0.006and0.012） in the EMA group were worse than those in the DIS and DMS groups.④The Spearman’s related analysis showed that the PM and DM results had arelationship with the education levels （Ps <0.05）, while have no relationship withgender and age （Ps>0.05）. Further partial correlation analysis （controlling theeducation levels） showed that there were no relationship between the experiment,movement sequence task and the free term memories （Ps>0.05）. Conclusion The PI patients have impairments of PM and DM at the same time, and thedegree of impairments depending on the memory testing task. The EMA in PI patientshave heavier memory impairment than the DIS and DMS. PM and DM may be aseparation effect.