Cognitive Impairment Of Neuromyelitis Optica Spectrum Disorders And Its Impact On Quality Of Life

BackgroundNeuromyelitis optica spectrum disorders(NMOSD)are central nervous system autoimmune demyelinating diseases.They were proposed by Wingerchuk in 2007 to extend the disease spectrum on the basis of optic neuromyelitis,and the diagnostic criteria was presented by the international NMO diagnostic team in 2015.In the past,neuromyelitis optica(NMO)lesions did not infringe the brain,only limited to the optic nerve and spinal cord,and the cognitive function of NMO patients was not impaired.However,researches on cognitive function of NMO patients in the last 10 years indicate that their cognitive function was indeed damaged.In 2008,Blanc first reported the impairment of cognitive function in NMO patients,suggesting that NMO patients have obstacles in working memory and information processing speed and verbal fluency.Recent studies have shown that more than half of NMOSD patients suffer cognitive decline.Optic neuritis and myelitis are common symptoms of NMOSD,and are easy to be identified.So far,there are still rare studies on whether the cognitive function will be different when lesions involving the optic nerve and spinal cord.NMOSD are recurrent diseases,making significant reduction in the quality of life of the patients.It is not known that whether the impaired cognitive function will reduce the quality of life.The aim of the treatment of NMOSD is to minimize the recurrence of the disease by using immunosuppressive agents,however,there is little inter vention for the impaired cognitive function and declining quality of life.This study will expolore whether the cognitive domain will be different when lesions involving the optic nerve,spinal cord,or the optic nerve and spinal cord at the same time,and the relationship between the decline of quality of life and cognitive dysfunction.PurposeTo study the difference of cognitive impairment when the lesion involves optic nerve or spinal cord in neuromyelitis optica spectrum disorders(NMOSD)and the effect of cognitive impairment on the quality of life.MethodAccording to the patients’ lesions,the patients were divided into the spinal cord group,the optic nerve group,the spinal cord+optic nerve group,the neuropsychological tests including Montreal cognitive assessment,Paced Auditory Serial Addition Test,Rey Auditory Verbal Learning Test,the Verbal fluency test,Digit span test were used to evaluate the overall cognitive fumction,memory,information processing speed,language function,attention,and the related factors that influence the cognitive function.The patients were divided into the overall cognitive dysfunction and the non-obstacle group,the domain cognitive dysfunction and the non-obstacle group,Multiple Sclerosis Quality of Life-54 scale(MSQOL-54)was used to compare their quality of life for each group.ResultsCognitive performance was significantly lower in the spinal cord group than in spinal cord+optic nerve group for MoCA(P=0.013),and was significantly lower in the spinal cord group and optic nerve group than in spinal cord+ optic nerve group forRAVLT N1-5(P=0.025,P=0.024)and VFT(P=0.000,P=0.028).Significant correlations between age and scores on MoCA,short-term memory,recognition memory,DS and between education level and scores on MoCA,PASAT-3s,PASAT-2s,short-term memory,short delay recall,long delay recall,recognition memory,VFT,DS and between EDSS and scores on short delay recall,long delay recall,recognition memory were found in NMOSD.Significant difference was found in total score of quality of life,physical dimension,mental dimension,overall quality of life,role limitations due to physical problems,cognitive functioning between the overall cognitive dysfunction and the non-obstacle group.Significant difference was found in total score of quality of life,mental dimension,social function,overall quality of life,role limitations due to physical problems,emotional well-being,cognitive functioning between word fluency impairment and nonobstacle group.Significant difference was found in overall quality of life between verbal memory impairment and non-disorder group.Significant correlations between total score of quality of life,physical dimension,mental dimension,social function,energy,role limitations due to physical problems,pain,emotional well-being,health perceptions and scores on PASAT-3s and between role limitations due to emotional problems and scores on VFT and DS.ConclusionsIn terms of cognitive function,short-term memory and language function are better in the spinal cord+ optic nerve group,however there were no significant difference between the spinal cord group and the optic nerve group.High education level is a protective factor to eognitive function for NMOSD patients.Word fluency,working memory and information processing speed and overall cognitive fimction all affect the quality of life of NMOSD patients.