Background Validation of the 2020 consensus criteria for primary lateral sclerosis (PLS) is essential for their use in clinical practice and future trials. Methods In a large cohort of patients diagnosed with PLS by expert opinion prior to the new criteria with detailed clinical baseline evaluation (n=107) and longitudinal follow-up (n=63), we applied the new diagnostic criteria and analysed the clinical phenotype, electromyography (EMG), diagnostic accuracy and prognosis, adding neurofilaments and MRI as potential biomarkers. Results The criteria for definite PLS were met by 28% and those for probable PLS by 19%, whereas 53% did not meet the full criteria at baseline, mainly due to the time, EMG and region criteria. Patients not meeting the criteria had less generalised upper motor neuron involvement but were otherwise similar in demographic and clinical characteristics. All patients with definite and probable PLS maintained PLS diagnosis during follow-up, while four patients not meeting the criteria developed clinical lower motor neuron involvement. Definite PLS cases showed improved survival compared with probable PLS and patients who did not meet the criteria. Despite a clinical PLS phenotype, fibrillation potentials/positive sharp waves and fasciculations in one or more muscles were a frequent EMG finding, with the extent and prognostic significance depending on disease duration. Serum neurofilament light and a multiparametric MRI fibre integrity Z-score correlated with clinical parameters and were identified as potential biomarkers. Conclusion Validation of the 2020 PLS consensus criteria revealed high diagnostic certainty and prognostic significance, supporting their value for research and clinical practice. Data are available upon reasonable request. The data that support the findings of this study are available from the authors upon reasonable request.

中文翻译：

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原发性侧索硬化症：2020 年共识诊断标准在基于专家意见的 PLS 队列中的应用和验证

背景 2020 年原发性侧索硬化症 (PLS) 共识标准的验证对于其在临床实践和未来试验中的使用至关重要。方法 在新标准实施前经专家意见诊断为 PLS 的一大群患者中，进行了详细的临床基线评估 (n=107) 和纵向随访 (n=63)，我们应用新的诊断标准并分析了临床表型、肌电图 (EMG)、诊断准确性和预后，添加神经丝和 MRI 作为潜在的生物标志物。结果 28% 的患者满足明确 PLS 的标准，19% 的患者满足可能 PLS 的标准，而 53% 的患者在基线时未满足全部标准，这主要是由于时间、肌电图和区域标准的原因。不符合标准的患者上运动神经元受累较少，但在人口统计学和临床​​特征方面相似。所有具有明确和可能 PLS 的患者在随访期间均维持 PLS 诊断，而 4 名不符合标准的患者出现临床下运动神经元受累。与可能的 PLS 和不符合标准的患者相比，确定的 PLS 病例的生存率有所提高。尽管存在临床 PLS 表型，但肌电图经常发现一根或多块肌肉中的颤动电位/正锐波和肌束颤动，其程度和预后意义取决于疾病持续时间。血清神经丝光和多参数 MRI 纤维完整性 Z 评分与临床参数相关，并被确定为潜在的生物标志物。结论 2020 PLS 共识标准的验证显示出较高的诊断确定性和预后意义，支持其研究和临床实践的价值。数据可根据合理要求提供。支持本研究结果的数据可根据合理要求向作者提供。