Unit of Pediatrics and Pediatric Emergency, University Hospital "Policlinico Vittorio Emanuele", Catania, Italy.
Section of Pediatrics and Child Neuropsychiatry, Department of Clinical and Experimental Medicine, University of Catania, Via Santa Sofia 78, 95100, Catania, Italy.
Neurol Sci. 2017 Sep;38(9):1723-1725. doi: 10.1007/s10072-017-3079-2. Epub 2017 Jul 26.
Microcephaly is defined as a head circumference measurement of 2 or 3 standard deviations below the mean for age and sex. However, distinguishing the value of -2 or -3 standard deviations as a cutoff is relevant in the clinical practice, since the limit of -3 standard deviations is more frequently associated with cognitive impairment. The use of ultrasound scans in pregnancy has allowed the identification of subjects with a measurement of the head circumference at the limit of the cutoff for gestational age, but who do not subsequently show cognitive delay. The same is true for newborns with a -2 to -3 standard deviations cutoff, and without anomalous clinical signs, for which a cognitive delay is not easily diagnosed. In this case, to define an infant as being affected by microcephaly (with a prognosis usually recognized as harmful) may be unnecessarily distressful for parents or caregivers. In the cases mentioned, resuming the word "small head" instead of microcephaly to define such subjects could be more appropriate and more appreciated.
小头畸形的定义为头围测量值低于同年龄、同性别平均值 2 或 3 个标准差。然而，在临床实践中，将 -2 或 -3 个标准差的数值作为截断值具有重要意义，因为 -3 个标准差的限值更常与认知障碍相关。在妊娠期间使用超声扫描，可以识别出在孕龄截断值范围内测量头围的受试者，但这些受试者随后并未出现认知延迟。对于头围在 -2 到 -3 个标准差截断值范围内的新生儿，且无异常临床体征的情况也是如此，对于这些新生儿，认知延迟不易被诊断。在这种情况下，将婴儿定义为患有小头畸形（预后通常被认为是有害的）可能会给父母或照顾者带来不必要的困扰。在上述情况下，用“小头”而不是“小头畸形”来定义这些受试者可能更合适，也更受认可。
