Feasibility study on shortening the detection time of long exercise test in the diagnosis of periodic paralysis
10.3760/cma.j.cn113694-20240627-00438
- VernacularTitle:缩短长时程运动试验检测时间在周期性麻痹诊断中的可行性探讨
- Author:
Shuo YANG
1
;
Na CHEN
1
;
Lin CHEN
1
;
Feng CHENG
1
;
Jingfen LI
1
;
Lei ZHANG
1
;
Ying WANG
1
;
Fan JIAN
1
;
Zaiqiang ZHANG
1
;
Hua PAN
1
Author Information
1. 首都医科大学附属北京天坛医院神经病学中心，北京 100070
- Publication Type:Journal Article
- Keywords:
Hypokalemic periodic paralysis;
Hyperkalemic periodic paralysis;
Periodic paralysis;
Long exercise test;
Compound muscle action potential;
Amplitude
- From:
Chinese Journal of Neurology
2025;58(4):359-365
- CountryChina
- Language:Chinese
-
Abstract:
Objective:To explore the feasibility of shortening the time of long exercise test (LET) from 120 to 60 minutes by analyzing the positive rate within 60 minutes among periodic paralysis (PP) patients who were positive in 120-minute test.Methods:The data of patients undergoing 120-minute LET from January 2015 to October 2021 in Beijing Tiantan Hospital, Capital Medical University were retrospectively analyzed, with 30%, 33%, and 40% as diagnostic cut-off values, respectively. PP patients with positive results within 120 minutes after exercise were enrolled in the study. The positive rate within 30 minutes and 60 minutes after exercise was calculated. The change rates of compound muscle action potential (CMAP) amplitude and the sensitivity and specificity of LET at 30 minutes, 60 minutes, and 120 minutes after exercise were analyzed. The change rate of CMAP amplitude in PP patients who did not show positive results within 60 minutes was further calculated.Results:A total of 254 patients were examined, including 114 PP patients. With 30%, 33%, and 40% as diagnostic cut-off values, the results showed that there were 88, 88, and 82 positive PP patients, respectively. Under each diagnostic cut-off values, the age of positive PP patients was (32±10) years, with a male proportion of 98% (86/88), 98% (86/88), and 99% (81/82), respectively; the positive rate of PP patients within 30 minutes after exercise was 60% (53/88), 58% (51/88), and 41% (34/82), respectively; the positive rate of PP patients within 60 minutes after exercise was 91% (80/88), 86% (76/88), and 83% (68/82), respectively. At the cut-off values of 30%, 33% and 40%, the change rate of CMAP amplitude at 30 minutes [-36% (-49%, -23%), -36% (-49%, -23%), -37% (-51%, -24%)], 60 minutes [-51% (-66%, -40%), -51% (-66%, -40%), -53% (-66%, -42%)] and 120 minutes [-57% (-67%, -45%), -57% (-67%, -45%), -58% (-67%, -46%)] after exercise showed statistically significant difference among 3 time points ( H=57.764, 57.764, 59.616, respectively, all P<0.001); the further comparison between time points showed that there was statistically significant difference in the change rate of CMAP amplitude between 60 minutes ( Z=5.419, 5.419, 5.531, respectively, all P<0.001), 120 minutes ( Z=7.325, 7.325, 7.431, respectively, all P<0.001) and 30 minutes after exercise, but there was no statistically significant difference in the change rate of CMAP amplitude between 120 minutes and 60 minutes after exercise ( Z=1.906, 1.906, 1.899, respectively, all P>0.05); the sensitivity of LET for the diagnosis of PP at 60 minutes after exercise was 70.2% (80/114), 66.7% (76/114) and 59.6% (68/114), and the specificity of LET for the diagnosis of PP was 77.9% (109/140), 84.3% (118/140) and 91.4%(128/140), respectively. When 30%, 33% and 40% were used as the diagnostic cut-off values, and the change rate of CMAP amplitude at 60 minutes after exercise fell below these cut-off values but showed a decline of ≥20%, ≥22% and ≥24%, respectively, the detection time should be extended to 120 minutes. Conclusions:Whether using 30%, 33%, or 40% as diagnostic cut-off values, it is feasible to shorten the LET time from 120 minutes to 60 minutes. The 60-minute LET has good sensitivity and specificity for the diagnosis of PP. It is recommended to extend the detection time to 120 minutes for patients with a ≥20%, ≥22%, or ≥24% decline in CMAP amplitude at 60 minutes after exercise while falling short of corresponding diagnostic cut-off values when 30%, 33%, and 40% are used as diagnostic cut-off values. This method can not only improve the examination efficiency of LET, but also minimize the missed diagnosis as much as possible.
