Definition and application of neuropsychological test battery to evaluate postoperative cognitive dysfunction

Objective To investigate the adequacy of the neuropsychological test battery proposed by the International Study of Postoperative Cognitive Dysfunction to evaluate this disorder in Brazilian elderly patients undergoing surgery under general anesthesia. Methods A neuropsychological assessment was made in patients undergoing non-cardiac surgery under general anesthesia, aged over 65 years, literate, with no history of psychiatric or neurological problems and score on the Mini Mental State Examination at or above the cutoff point for the Brazilian population (&gt;18 or &gt;23) according to the schooling level of the subject. Eighty patients were evaluated by a trained team of neuropsychologists up to 24 hours before elective surgery. Results Among the patients evaluated, one was excluded due to score below the cutoff point in the Mini Mental State Examination and two did not complete the test battery, thus remaining 77 patients in the study. The mean age was 69±7.5 years, and 62.34% of the subjects had ±4 years of study. The subjects had significantly lower averages than expected (p&lt;0.001) for normative tables on neuropsychological tests. Conclusion The study demonstrated the applicability of the instruments in the Brazilian elderly and low schooling level population, but suggested the need to determine cutoff points appropriate for these individuals, ensuring the correct interpretation of results. This battery is relevant to postoperative follow-up evaluations, favoring the diagnosis of postoperative cognitive dysfunction in patients undergoing different types of surgery and anesthetic techniques.研究目的：本研究旨在探讨国际术后认知功能障碍研究（International Study of Postoperative Cognitive Dysfunction）提出的神经心理学测试组合（neuropsychological test battery），用于评估接受全身麻醉（general anesthesia）手术的巴西老年患者术后认知功能障碍（Postoperative Cognitive Dysfunction）的适用性。 研究方法：本研究纳入年龄≥65岁、具备读写能力、无精神或神经系统疾病史，且根据受教育程度符合巴西人群简易精神状态检查表（Mini Mental State Examination, MMSE）截断值（≥18分或≥23分）的择期非心脏手术全身麻醉患者，对其实施神经心理学评估。由经过培训的神经心理学团队在择期手术前24小时内完成对80例患者的评估。 研究结果：纳入评估的患者中，1例因简易精神状态检查表得分低于截断值被排除，2例未完成全部测试组合，最终纳入有效病例77例。受试者平均年龄为69±7.5岁，62.34%的受试者受教育年限≤4年。受试者在神经心理学测试常模表中的平均得分显著低于预期值（p<0.001）。 研究结论：本研究证实了该测试组合在巴西老年低教育水平人群中的适用性，但提示需针对该人群制定专属截断值，以确保结果解读的准确性。该测试组合可用于术后随访评估，有助于对接受不同手术类型与麻醉技术的患者做出术后认知功能障碍的诊断。