Evaluation of negation phrases in narrative clinical reports
Evaluation of negation phrases in narrative clinical reports
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发表时间：
2001
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通讯作者：
W. Chapman;Will Bridewell;P. Hanbury;G. Cooper;B. Buchanan
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作者：
W. Chapman;Will Bridewell;P. Hanbury;G. Cooper;B. Buchanan
自动识别临床文本报告中描述的发现或疾病需要确定是否存在临床观察结果。我们评估了在自由文本临床报告中否定短语的使用和否定的频率。方法应用简单否定算法对2000年7月期间口述的10种类型的临床报告（n=42,160）进行分析。我们计算了66个否定短语中的每一个用于将临床观察标记为不存在的频率。医生们随机阅读了400个句子，并计算了否定短语的精确度。我们测量了标记为不存在的临床观察结果的比例。结果该否定算法由60个否定短语触发，其中7个短语占90%的否定。否定短语的整体准确率为97%，其中“not”的准确率最低，为63%。根据分析的报告类型，否定算法将39%至83%的所有临床观察结果确定为不存在。大多数情况下，最常用的临床观察结果被否定。结论由于文本病历中的临床观察结果经常被否定，因此识别准确的否定短语对任何处理这些报告的系统都很重要。
OBJECTIVE Automatically identifying findings or diseases described in clinical textual reports requires determining whether clinical observations are present or absent. We evaluate the use of negation phrases and the frequency of negation in free-text clinical reports. METHODS A simple negation algorithm was applied to ten types of clinical reports (n=42,160) dictated during July 2000. We counted how often each of 66 negation phrases was used to mark a clinical observation as absent. Physicians read a random sample of 400 sentences, and precision was calculated for the negation phrases. We measured what proportion of clinical observations were marked as absent. RESULTS The negation algorithm was triggered by sixty negation phrases with just seven of the phrases accounting for 90% of the negations. The negation phrases received an overall precision of 97%, with "not" earning the lowest precision of 63%. Between 39% and 83% of all clinical observations were identified as absent by the negation algorithm, depending on the type of report analyzed. The most frequently used clinical observations were negated the majority of the time. CONCLUSION Because clinical observations in textual patient records are frequently negated, identifying accurate negation phrases is important to any system processing these reports.