Oates Peggy A, Kurtzberg Diane, Stapells David R
Department of Communication Services and Disorders, Towson University, Maryland 21252-0001, USA.
Ear Hear. 2002 Oct;23(5):399-415. doi: 10.1097/00003446-200210000-00002.
To investigate systematically the effects of sensorineural hearing loss on cortical event-related potentials (ERPs) N1, MMN, N2 and P3 and their associated behavioral measures (d' sensitivity and reaction time) to the speech sounds /ba/ and /da/ presented at 65 and 80 dB ppe SPL.
Cortical ERPs were recorded to /ba/ and /da/ speech stimuli presented at 65 and 80 dB ppe SPL from 20 normal-hearing adults and 20 adults who are hearing impaired. The degree of sensorineural impairments at 1000 to 2000 Hz ranged from mild losses (defined as 25 to 49 dB HL) to severe/profound losses (75 to 120 dB HL). The speech stimuli were presented in an oddball paradigm and the cortical ERPs were recorded in both active and passive listening conditions for each stimulus intensity.
Both ERP amplitudes and behavioral discrimination (d') scores were lower for listeners with sensorineural hearing loss than for those with normal hearing. However, these differences in response strength were evident only for those listeners whose average hearing loss at 1000 to 2000 Hz exceeded 60 dB HL for the lower intensity stimuli and exceeded 75 dB HL for the higher intensity stimuli. In contrast, prolongations in the ERP and behavioral latencies, relative to responses from normal-hearing subjects, began with even mild (25 to 49 dB HL) threshold elevations. The amplitude and latency response changes that occurred with sensorineural hearing loss were significantly greater for the later ERP peaks (N2/P3) and behavioral discrimination measures (d' and RT) in comparison with earlier (N1, MMN) responses.
The results indicate that latency measures are more sensitive indicators of the early effects of decreased audibility than are response strength (amplitude, d' or percent correct) measures. Sensorineural hearing loss has a greater impact on higher level or "nonsensory" cortical processing in comparison with lower level or "sensory" cortical processing. Possible physiologic mechanisms within the cortex that may be responsible for these response changes are presented. Lastly, the possible clinical significance of these ERP and behavioral findings is discussed.
系统研究感音神经性听力损失对皮质事件相关电位（ERP）的N1、MMN、N2和P3成分，以及对以65分贝声压级等效峰值声压（ppe SPL）和80分贝ppe SPL呈现的语音/ba/和/da/的相关行为指标（d'敏感性和反应时间）的影响。
记录20名听力正常的成年人和20名听力受损成年人在65分贝ppe SPL和80分贝ppe SPL下对/ba/和/da/语音刺激的皮质ERP。1000至2000赫兹的感音神经性损伤程度从轻度听力损失（定义为25至49分贝听力级[HL]）到重度/极重度听力损失（75至120分贝HL）不等。语音刺激以奇偶数范式呈现，每种刺激强度在主动和被动聆听条件下记录皮质ERP。
感音神经性听力损失的听众的ERP波幅和行为辨别（d'）分数均低于听力正常的听众。然而，仅对于那些在1000至2000赫兹平均听力损失对于较低强度刺激超过60分贝HL且对于较高强度刺激超过75分贝HL的听众，这些反应强度差异才明显。相比之下，相对于听力正常受试者的反应，ERP和行为潜伏期的延长甚至始于轻度（25至49分贝HL）阈值升高。与早期（N1、MMN）反应相比，感音神经性听力损失时发生的波幅和潜伏期反应变化在后期ERP波峰（N2/P3）和行为辨别指标（d'和反应时间[RT]）上更为显著。
结果表明，潜伏期指标比反应强度（波幅、d'或正确百分比）指标更能敏感地反映可听度降低的早期影响。与较低水平或“感觉”皮质处理相比，感音神经性听力损失对较高水平或“非感觉”皮质处理的影响更大。提出了皮质内可能导致这些反应变化的生理机制。最后，讨论了这些ERP和行为研究结果可能的临床意义。
