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Objectives: To evaluate sound localization ability in totally deaf patients with unilateral cochlear implants and to estimate the ability to improve this function by training.Design: A controlled case series.Materials and Methods: Nine patients with monaural cochlear implants were asked to identify the source of 50 randomly distributed sound stimuli coming from five different directions anteriorly or laterally. After some training, patients were retested. There were two control groups. One comprised nine adults with normal hearing, and the other comprised nine adults with normal hearing but one ear plugged.Results: The mean initial score of the study group (maximal score 100) was 41.5 (range 23-63). Patients who had used cochlear implants longer had better sound localization ability (Spearman's correlation coefficient = 0.92). On retesting, after an average of 6.3 training sessions, their mean score improved to 66 (range 32-95), (p = 0.008). The improvement was more pronounced in postlinguals than in prelinguals (p = 0.016).Conclusions: Spontaneous development of sound localization ability in totally deaf patients with unilateral cochlear implants is proportional to the time interval between implantation and initial testing. Improvement appears to be influenced by training, and to be greater in postlingual than in prelingual implantees. [ABSTRACT FROM AUTHOR]

Presents information on a study which examined the effects of sound source direction and elevation on human brainstem electrical activity associated with sound localization. Materials and methods of the study; Results of the study; Discussion on the study.

The authors used a semantic priming paradigm to investigate the distractibility phenomenon of patients with frontal lobe lesions (FLPs). They tested two disractibility categories: an inhibition category requiring inhibition of an automatic response and a unexpected stimuli. Fifteen FLPs were compared with 2 mathed control groups: 14 posterior-lesion patients and 15 normal controls. Both behavioral and event-related brain potential (ERP) measures were used. The results suggest that, although there were differences in performance between the FLP group and the control groups, there was no evidence that the FLPs had difficulty specifically with the inhibition category. The most consistent ERP result was that the FLP group had longer N100 latencies than either control group. On the basis of these results, the authors hypothesize that FLPs have difficulty focusing on and starting to process a new stimulus. The authors also discuss the unique contribution ERP evidence has made to cognitive studies. [ABSTRACT FROM AUTHOR]

ABSTRACT. The selectivity of frontal lobe lesion effects in the domains of verbal-information processing has not been well established. The authors hypothesized that capacity-limited controlled processing would be more impaired than automatic processing in frontal lobe patients (FLPs). Fifteen FLPs were compared with 2 matched control groups: 14 posterior-lesion patients and 15 normal controls. Both behavioral and event-related brain potential (ERP) measures were collected. Results suggest that both automatic and controlled processing were affected by frontal lobe lesions. ERP results indicated that the main difficulty for the FLPs was in the perceptual stage of information processing. This rather unexpected result may be explained by a basic difficulty of FLPs in attending to a new stimulus in order to process it. [ABSTRACT FROM AUTHOR]