| ObjectiveGuillain-Barre syndrome(GBS),an acute immune-mediated polyneuropathy,mainly manifests an acute or subacute progressive symmetric weakness of distal limbs with or without sensory deficits,involvement of respiratory muscles,cranial nerve-innervated muscles,or autonomic function.The crude incidence of the GBS is estimated at 0.81 to 1.89 per 100,000 per year.To data,the GBS disability score and MRC sum-score,which precisely define the levels of motor function,are widely used scoring system to evaluate the severity and functional status of patients with GBS.However,reviewing the previous literature,in the acute phase of GBS,many factors,such as mechanical ventilation and severe autonomic dysfunction,have close relationship with the severity of disease.Therefore,clinicians should pay close attention to the full spectrum of symptoms that indicate urgent threats to a patient's life,and avoid an overly narrow reliance on motor function assessments.Given these considerations,the study reported here aimed to develop a scale that can more comprehensively evaluate the severity of GBS.Methods258 patients who fulfilled the inclusive criteria were enrolled through the neurology departments of the First and Second affiliated hospitals of our university from September 2014 to December 2016.Among these patients,100(group 1)were assessed for quantitative analysis of scale items.Reliability and validity tests were performed on the remaining 158 patients(group 2).Data were collected when symptoms reached their peak.In order to form the primary item pool,we reviewed literature on GBS in recent fifteen years and summarized factors which present in the acute stage of disease relating to mechanical ventilation and short-time poor prognosis.After that,The Delphi method was used to assess the importance of all items.For quantifying all items,the Maximum Likelihood Discriminating Method and Analytic Hierarchy Process were chosen to complete the score calculation.After that,one hundred cases were assigned to accomplish the item analysis,and additional one hundred and fifty-eight cases were assigned to analysis of the reliability and validity of the scale.Results 1.Demographic characteristics of all patientsOf the 258 patients,100 patients were assigned to group 1,which had male: female ratio of 58: 42 and a mean age of 43±17 years.The remaining 158 patients were assigned to group 2,which had a male: female ratio of 94: 64,and a mean age of 45±14 years.2.Qualitative evaluation of itemsThere were 12 items in the preliminary item pool.1 item was deleted because of a below average score.According to expert suggestions,2 items were modified.Ultimately,11 items reached a consensus,and the average scores were above 3.5.The Kendall's coefficient of concordance of expert opinions was 0.581,p<0.01.3.Quantification of itemsSee table 1 in the appendix 4.Item analysisAll items complied with the rules of frequency distribution.The sum-scores of rating scales for the 100 patients were calculated according to the principle of critical ratio.The low-scoring group,which was defined as the top 20% of total scores,was compared by ttest with the high-scoring group,which was defined as the bottom 20% of total scores,and we observed a statistically significant difference(t=-29.89,p<0.05).In spearman's correlation analysis,the correlation coefficients between items and the rating scale were above 0.4,ranging from 0.463 to 0.894,except for item 11(abnormal sweating),which had a correlation coefficient of 0.398.Item 11 was therefore deleted,and the rating scale thus ultimately consisted of 10 items.5.Reliability,Validity,and ResponsivityThe results of reliability and validity showed that the structure of the rating scale was good(?2= 68.25,df = 32,?2/ df =2.13,normed fit index(NFI)=0.919,non-normed fit index(NNFI)=0.936,comparative fit index(CFI)=0.96,a root mean square error of approximation(RMSEA)=0.085),and the Cronbach's ? coefficient for the scale was 0.852,with the three dimensions ranging from 0.585 to 0.752.The 1-week test-retest for the rating scale was 0.842,and the 3 dimensions were 0.808,0.621,and 0.593.In responsivity analysis,scores of the total scale and different dimensions between the two subgroups were statistical difference(p<0.05).ConclusionWe have developed a primary scale for assessing the severity of GBS.All items in this rating scale show the main characteristics of GBS,and satisfy the criteria for qualitative and quantitative evaluations of scale quality.Therefore,our scale is a practical and accurate tool for evaluating the severity of GBS. |
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