Jones S J, Sprague L, Vaz Pato M
The National Hospital for Neurology and Neurosurgery, London, UK.
J Neurol Neurosurg Psychiatry. 2002 Nov;73(5):561-7. doi: 10.1136/jnnp.73.5.561.
To assess the processing of spectrotemporal sound patterns in multiple sclerosis by using auditory evoked potentials (AEPs) to complex harmonic tones.
22 patients with definite multiple sclerosis but mild disability and no auditory complaints were compared with 15 normal controls. Short latency AEPs were recorded using standard methods. Long latency AEPs were recorded to synthesised musical instrument tones, at onset every two seconds, at abrupt frequency changes every two seconds, and at the end of a two second period of 16/s frequency changes. The subjects were inattentive but awake, reading irrelevant material.
Short latency AEPs were abnormal in only 4 of 22 patients, whereas long latency AEPs were abnormal to one or more stimuli in 17 of 22. No significant latency prolongation was seen in response to onset and infrequent frequency changes (P1, N1, P2) but the potentials at the end of 16/s frequency modulations, particularly the P2 peaking approximately 200 ms after the next expected change, were significantly delayed.
The delayed responses appear to be a mild disorder in the processing of change in temporal sound patterns. The delay may be conceived of as extra time taken to compare the incoming sound with the contents of a temporally ordered sensory memory store (the long auditory store or echoic memory), which generates a response when the next expected frequency change fails to occur. The defect cannot be ascribed to lesions of the afferent pathways and so may be due to disseminated brain lesions visible or invisible on magnetic resonance imaging.
通过使用对复杂谐波音调的听觉诱发电位（AEP）来评估多发性硬化症患者对频谱时间声音模式的处理能力。
将22例确诊为多发性硬化症但残疾程度较轻且无听觉主诉的患者与15名正常对照者进行比较。采用标准方法记录短潜伏期AEP。记录对合成乐器音调的长潜伏期AEP，每两秒开始一次，每两秒频率突然变化一次，以及在16次/秒频率变化的两秒时间段结束时。受试者注意力不集中但清醒，阅读无关材料。
22例患者中只有4例短潜伏期AEP异常，而22例中有17例对一种或多种刺激的长潜伏期AEP异常。对开始和不频繁的频率变化（P1、N1、P2）未观察到明显的潜伏期延长，但在16次/秒频率调制结束时的电位，特别是在下一次预期变化后约200毫秒达到峰值的P2电位，明显延迟。
延迟反应似乎是时间声音模式变化处理中的一种轻度障碍。这种延迟可以被认为是将传入声音与按时间顺序排列的感觉记忆存储（长时听觉存储或回声记忆）的内容进行比较所花费的额外时间，当预期的下一次频率变化未发生时，该存储会产生反应。这种缺陷不能归因于传入通路的病变，因此可能是由于磁共振成像上可见或不可见的弥漫性脑病变所致。
