Development of visual attention skills in prelingually deaf children who use cochlear implants

Abstract

Objective: To determine the effects of length of cochlear implant use and other demographic factors on the development of sustained visual attention in prelingually deaf children and to examine the relations between performance on a test of sustained visual attention and audiological outcome measures in this population.

Design: A retrospective analysis of data collected before cochlear implantation and over several years after implantation. Two groups of prelingually deaf children, one >6 years old (N = 41) and one <6 years old (N = 47) at testing, were given an age-appropriate Continuous Performance Task (CPT). In both groups, children monitored visually presented numbers for several minutes and responded whenever a designated number appeared. Hit rate, false alarm rate, and signal detection parameters were dependent measures of sustained visual attention. We tested for effects of a number of patient variables on CPT performance. Multiple regression analyses were conducted to determine if CPT scores were related to performance on several audiological outcome measures.

Results: In both groups of children, mean CPT performance was low compared with published norms for normal-hearing children, and performance improved as a function of length of cochlear implant use and chronological age. The improvement in performance was manifested as an increase in hit rate and perceptual sensitivity over time. In the younger age group, a greater number of active electrodes predicted better CPT performance. Results from regression analyses indicated a relationship between CPT response criterion and receptive language in the younger age group. However, we failed to uncover any other relations between CPT performance and speech and language outcome measures.

Conclusions: Our findings suggest that cochlear implantation in prelingually deaf children leads to improved performance on a test of sustained visual processing of numbers over 2 or more years of cochlear implant use. In preschool-age children who use cochlear implants, individuals who are more conservative responders on the CPT show higher receptive language scores than do individuals with more impulsive response patterns. Theoretical accounts of these findings are discussed, including cross-modal reorganization of visual attention and enhanced phonological encoding of visually presented numbers.

Fig. 1

School-age vigilance CPT performance improves as a function of chronological age. Hit rate (a) and perceptual sensitivity (b) both increase with chronological age. Each data point represents the CPT score (mean hit rate or mean d′) for one participant tested at the 2-year interval of cochlear implant use. Several data points overlap because some participants had identical mean CPT scores. Two lines representing the 85th and 15th percentiles for hit rate based on normative data are included in (a) for comparison purposes.

Fig. 2

School-age vigilance CPT performance improves as a function of length of cochlear implant use. Mean hit rate (a) and d′ (b) both increase with length of cochlear implant use. Each data point represents the estimated mean CPT performance from the SAS mixed model at a given year of cochlear implant use. Error bars indicate standard error. Different shaped/shaded data points represent significant differences in mean CPT performance as determined by post hoc analyses. The exception is that mean performance at year 0 did not differ significantly from performance at any subsequent interval. This probably is due to the large degree of variability in CPT performance before implantation.

Fig. 3

Preschool vigilance CPT performance improves as a function of chronological age (a and b). Hit rate (Fig. 1a) and perceptual sensitivity (Fig. 1b) both increase with chronological age. Each data point represents the mean CPT score (mean hit rate or mean d′) for one participant tested at the 1-year interval of cochlear implant use. Several data points overlap because some participants had identical mean CPT scores. Two lines representing the 85th and 15th percentiles for hit rate based on normative data are included in (a) for comparison purposes.

Fig. 4

Preschool vigilance CPT performance improves as a function of length of cochlear implant use. Mean hit rate (a) and d′ (c) both increase, whereas mean false alarm rate (b) decreases with length of cochlear implant use. Each data point represents the estimated mean CPT performance from the SAS mixed model at a given year of cochlear implant use. Error bars indicate standard error. Different shaped/shaded data points represent significant differences in mean CPT performance as determined by post hoc analyses.