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Auditory training and cognitive functioning in adult with traumatic brain injury

2011; Elsevier BV; Volume: 66; Issue: 4 Linguagem: Inglês

10.1590/s1807-59322011000400030

1980-5322

Cristina Ferraz Borges Murphy, Renata Fillippini, Debora Palma, Tatiane Eisencraft Zalcman, Janaína Patrício Lima, Eliane Schochat,

Traumatic Brain Injury Research

Auditory training (AT) is a set of strategies applied to develop or improve auditory abilities.1 Two mechanisms are involved in auditory processing: neurocognitive mechanisms of the acoustic signal itself, which are responsible for the discrimination and recognition of a specific function (“bottom-up” processes), and attentional processes involving phenomena such as attention and memory (“top-down” processes). Several studies have shown that auditory functions can be improved by stimulating those neurocognitive and attentional abilities.2,3 Nevertheless, it is not yet known whether AT can improve cognitive functioning. Although AT shares processes in common with cognition (such as attentional processes), it considers the processes as solely unimodal because only auditory stimuli are analyzed. This leads to the question of whether auditory training affects cognitive abilities. This paper describes the audiological and cognitive findings of an adult with traumatic brain injury (TBI) before and after AT. Case This study, no. 0163/09, was approved by the Ethics Committee for the Analysis of Research Projects (CAPPesq) of the Hospital das Clinicas da Faculdade de Medicina da Universidade de Sao Paulo in 2009. A 49-year old man, complaining that he could not understand people when they spoke, sought the Audiology service of Faculdade de Medicina da Universidade de Sao Paulo to undergo auditory testing. In the anamnesis, the patient reported that he began to have difficulty understanding speech when he was knocked over in 1997. The report issued by the hospital on the day of the accident describes an occipital subgaleal hematoma D, acute frontal subdural hematoma E and otorrhage E. In the right hemisphere there was a longitudinal base fracture with polytrauma. The neurological examination showed a Glasgow scale score of 12, a state of aphasia and psychomotor agitation. Subsequent neurological examinations (2000) reported permanent debility in the senses of hearing and smell linked to the traumatic event. The patient reports that he has not had any type of rehabilitation therapy since the accident. The audiological tests applied included audiometry, immittance measures, behavioral tests of central auditory processing, and the measurement of the P300 component of the LAEPs (Long Latency Auditory Evoked Potentials). A two-channel audiometer (GSI 61; Grason Stadler) was used for audiometry, and a GSI 33 middle ear analyzer (Grason Stadler) was used for immittance measurements. Electrophysiological procedures were carried out using a Bio-logic Navigator Pro. To analyze the latency and amplitude of the P300 wave, click stimuli were presented at 70 dB HL at a rate of 1.1/sec. The audiometric assessment revealed mild neurosensory hearing loss with descendent configuration. All auditory processing tests were performed at 40 dB SL from the average frequencies of 500, 1000 and 2000 Hz. The auditory processing tests showed a moderate disorder with impairment of the following abilities: figure-ground to linguistic sounds (PSI and SSW), temporal pattern (Frequency Pattern Sequence) and verbal memory. Thus, the auditory training was prescribed for rehabilitate the abilities altered and later reassessment. Language was also assessed using the following tests: Boston Test, MAC Battery, TROG protocol, Token Test, and the working memory test. The patient's performance was below that expected in tasks of graphic and oral comprehension, figurative or non-literal language and alteration of working memory. The patient remains on a waiting list for language rehabilitation. The AT took place in an acoustic cabin for 8 sessions of 40 minutes each. The difficulty level of the AT program was manually set for each test and session to maintain a success/failure rate of approximately 70/30%.4 Before and after the training, cognitive functions were also investigated through the application of a Brief Cognitive Battery.5 The results showed performance below the expected level in some tasks, such as verbal fluency and incidental memory. After 8 sessions of auditory training, the patient underwent audiological and cognitive assessments once more (Post-training 1). The patient reported an improvement in the ability to understand speech, and the results showed performance improvements in most of the applied behavioral auditory tests (Table 1). Improvements were also noted in the P300 wave morphology, with an increase in amplitude in both ears and a decrease in latency in the right ear (Figure 1). In addition, an improvement in performance was observed in 5 of the 7 cognitive abilities analyzed, also shown in the Table 1. Figure 1 Results of the P300 Long-Latency Evoked Auditory, test in both ears, pre- and post-auditory training. A: LEFT EAR, PRE-TRAINING: latency 348,98 ms, amplitude 5,07 µV; POST-TRAINING I: latency 365,64 ms, amplitude 7,11 µV; ... Table 1 Auditory processing and cognitive abilities pre- and post-treatment. To investigate whether any consolidation of learning occurred, a re-assessment was performed after approximately 4 months (Post-training 2). Concerning auditory processing, the patient maintained a similar performance level on most of the tests on which he had shown a post-training improvement (SSW, PSI, Speech with Noise) and a slight drop in performance on the Frequency Pattern and Memory for Oral Sounds tests (Table 1). In the cognitive tests, a slight drop in performance occurred on most of the tests on which the patient had shown an improvement (Delayed Recall, Immediate and Incidental Memory, Recognition). The values obtained in the P300 wave morphology also worsened, with a reduction in amplitude and an increase in latency observed in both ears (Figure 1).