Robert H. Eikelboom

Registration of stereo and temporal images of the retina

The registration of retinal images is required to facilitate the study of the optic nerve head and the retina. The method the authors propose combines the use of mutual information as the similarity measure and simulated annealing as the search technique. It is robust toward large transformations between the images and significant changes in light intensity. By using a pyramid sampling approach combined with simulated reannealing the authors find that registration can be achieved to predetermined precision, subject to choice of interpolation and the constraint of time. The algorithm was tested on 49 pairs of stereo images and 48 pairs of temporal images with success.

Validity of Automated Threshold Audiometry: A Systematic Review and Meta-Analysis.

OBJECTIVES A systematic literature review and meta-analysis on the validity (test-retest reliability and accuracy) of automated threshold audiometry compared with the gold standard of manual threshold audiometry was conducted. DESIGN A systematic literature review was completed in peer-reviewed databases on automated compared with manual threshold audiometry. Subsequently a meta-analysis was conducted on the validity of automated audiometry. METHODS A multifaceted approach, covering several databases and using different search strategies was used to ensure comprehensive coverage and to cross-check search findings. Databases included: MEDLINE, Scopus, and PubMed; a secondary search strategy was the review of references from identified reports. Reports including within-subject comparisons of manual and automated threshold audiometry were selected according to inclusion/exclusion criteria before data were extracted. For the meta-analysis weighted mean differences (and standard deviations) on test-retest reliability for automated compared with manual audiometry were determined to assess the validity of automated threshold audiometry. RESULTS In total, 29 reports on automated audiometry (method of limits and the method of adjustment techniques) met the inclusion criteria and were included in this review. Most reports included data on adult populations using air conduction testing with limited data on children, bone conduction testing and the effects of hearing status on automated audiometry. Meta-analysis test-retest reliability for automated audiometry was within typical test-retest variability for manual audiometry. Accuracy results on the meta-analysis indicated overall average differences between manual and automated air conduction audiometry (0.4 dB, 6.1 SD) to be comparable with test-retest differences for manual (1.3 dB, 6.1 SD) and automated (0.3 dB, 6.9 SD) audiometry. No significant differences (p > 0.01; summarized data analysis of variance) were seen in any of the comparisons between test-retest reliability of manual and automated audiometry compared with differences between manual and automated audiometry. CONCLUSION Automated audiometry provides an accurate measure of hearing threshold, but validation data are still limited for (1) automated bone conduction audiometry; (2) automated audiometry in children and difficult-to-test populations and; (3) different types and degrees of hearing loss.Objectives: A systematic literature review and meta-analysis on the validity (test–retest reliability and accuracy) of automated threshold audiometry compared with the gold standard of manual threshold audiometry was conducted. Design: A systematic literature review was completed in peer-reviewed databases on automated compared with manual threshold audiometry. Subsequently a meta-analysis was conducted on the validity of automated audiometry. Methods: A multifaceted approach, covering several databases and using different search strategies was used to ensure comprehensive coverage and to cross-check search findings. Databases included: MEDLINE, Scopus, and PubMed; a secondary search strategy was the review of references from identified reports. Reports including within-subject comparisons of manual and automated threshold audiometry were selected according to inclusion/exclusion criteria before data were extracted. For the meta-analysis weighted mean differences (and standard deviations) on test–retest reliability for automated compared with manual audiometry were determined to assess the validity of automated threshold audiometry. Results: In total, 29 reports on automated audiometry (method of limits and the method of adjustment techniques) met the inclusion criteria and were included in this review. Most reports included data on adult populations using air conduction testing with limited data on children, bone conduction testing and the effects of hearing status on automated audiometry. Meta-analysis test–retest reliability for automated audiometry was within typical test–retest variability for manual audiometry. Accuracy results on the meta-analysis indicated overall average differences between manual and automated air conduction audiometry (0.4 dB, 6.1 SD) to be comparable with test–retest differences for manual (1.3 dB, 6.1 SD) and automated (0.3 dB, 6.9 SD) audiometry. No significant differences (p > 0.01; summarized data analysis of variance) were seen in any of the comparisons between test–retest reliability of manual and automated audiometry compared with differences between manual and automated audiometry. Conclusion: Automated audiometry provides an accurate measure of hearing threshold, but validation data are still limited for (1) automated bone conduction audiometry; (2) automated audiometry in children and difficult-to-test populations and; (3) different types and degrees of hearing loss.

Telemedicine Screening of Diabetic Retinopathy Using a Hand-Held Fundus Camera

The objective was to evaluate digital images of the retina from a handheld fundus camera (Nidek NM-100) for suitability in telemedicine screening of diabetic retinopathy. A handheld fundus camera (Nidek) and a standard fundus camera (Zeiss) were used to photograph 49 eyes from 25 consecutive patients attending our diabetic clinic. One patient had cataracts, making it impossible to get a quality image of one of the eyes (retina). The Nidek images were digitized, compressed, and stored in a Fujix DF-10M digitizer supplied with the camera. The digital images and the photographs were presented separately in a random order to three ophthalmologists. The quality of the images was ranked as good, acceptable or unacceptable for diabetic retinopathy diagnosis. The images were also evaluated for the presence of microaneurysms, blot hemorrhages, exudates, fibrous tissue, previous photocoagulation, and new vessel formation. kappa Values were computed for agreement between the photographs and digital images. Overall agreement between the photographs and digital images was poor (kappa < 0.30). On average, only 24% of the digital images were graded as being good quality and 56% as having an acceptable quality. However, 93% of the photographs were graded as good-quality images for diagnosis. The results indicate that the digital images from the handheld fundus camera may not be suitable for diagnosis of diabetic retinopathy. The images shown on the liquid crystal display (LCD) screen of the camera were of good quality. However, the images produced by the digitizer (Fujix DF-10M) attached to the camera were not as good as the images shown on the LCD screen. A better digitizing system may produce better quality images from the Nidek camera.

Eliminating the Limitations of Manual Crimping in Stapes Surgery? A Preliminary Trial with the Shape Memory Nitinol Stapes Piston

Objective: Manual piston malcrimping in stapedotomy may be the major cause of the occurrence of the significant, interindividual variations of postoperative air‐bone gap (ABG), air‐bone gap closures (ABGC), and postoperative recurrences of conductive hearing loss. To eliminate the effects of manual crimping on stapedotomy outcomes, the self‐crimping, shape memory alloy Nitinol stapes piston was investigated and hearing evaluated.

Attitude to telemedicine, and willingness to use it, in audiology patients

We studied the willingness of patients to use telemedicine for ear- and hearing-related appointments, and the factors that influenced their decision to participate in telemedicine. A survey was designed with questions about patient appointments, perceived advantages and barriers to telemedicine, and prior use of the Internet for health-related matters. A total of 116 patients in four audiology centres were surveyed from December 2004 to May 2005. There were 54 male and 62 female respondents; 46% of the participants were aged over 66 years. In all, 75% had not previously heard of telemedicine. The most common reasons for willingness to use telemedicine were to reduce the time waiting for an appointment and cost. The most common barrier to using telemedicine was a preference for face-to-face visits. Of those surveyed, 32% were willing to use telemedicine, 10% would sometimes be willing, 28% were unsure, and 30% were not willing. There was no relationship between willingness and age or gender, except that women over the age of 55 years were less willing. Patients who had previously heard of telemedicine and used the Internet for health-related matters, especially men, were more inclined to have a telemedicine appointment.

Long-term benefit perception, complications, and device malfunction rate of bone-anchored hearing aid implantation for profound unilateral sensorineural hearing loss.

Objective: To longitudinally evaluate short- and long-term subject satisfaction/benefit perception, device usage rates, complication rates, and external device repair rates of bone-anchored hearing aid (BAHA) implantation on a cohort of adult subjects with profound unilateral sensorineural hearing loss (PUSHL). Study Design: Prospective clinical trial. Setting: Tertiary referral center. Patients: Fifty-six adults with PUSHL, 21 of which underwent BAHA implantation (followed for an average of 3.2 years after implantation; range, 0.8-4.6 yr). Main Outcome Measures: Short- and long-term satisfaction/benefit perception outcomes consisting of the Glasgow Hearing Aid Benefit Profile, Abbreviated Profile of Hearing Aid Benefit, and Single-Sided Deafness Questionnaire, including a comparison of results between implanted and nonimplanted subjects. Short- and long-term device usage rates, complications, and device failure issues also were carefully documented. Results: There were statistically significant improvements in nearly all measures of benefit perception documented as well as a high rate of long-term device usage (81%). Although satisfaction and benefit perception outcomes generally tended to regress over time when compared with initial short-term outcomes, long-term scores still tended to be significantly improved nevertheless as compared with preoperative levels. Approximately 38% of implants experienced severe local skin reactions (Grade 2 and above) around the implant site at some point throughout the follow-up period, whereas only one (4.8%) required implant removal. 66.7% of subjects required repair of their external sound processor. Conclusion: BAHA implantation seems to provide a high level of short- and long-term perceived benefit and satisfaction in subjects with PUSHL and high rate of long-term device usage. Implant site adverse local skin reactions and repairs of the external sound processor were quite common.

Evaluation of a portable fundus camera for use in the teleophthalmologic diagnosis of glaucoma.

PURPOSE The digital images of the optic disk from a portable fundus camera were evaluated for suitability in teleophthalmologic screening for glaucoma. METHODS Fifty-one eyes of 27 consecutive patients from our glaucoma clinic were dilated and photographed with a Zeiss FF retinal camera (Carl Zeiss, Oberkochen, Germany) and a portable Nidek NM-100 (Nidek, Tokyo, Japan) fundus camera. Digital images from the portable fundus camera were digitized, compressed and stored in a Fujix DF-10M (Fuji, Tokyo, Japan) digitizer. Lossy compressed digital images and photographs from the Zeiss camera were presented separately in random order to three ophthalmologists for estimation of vertical cup:disk ratios (VCDR) and to evaluate image quality as good, acceptable, or unacceptable for screening glaucoma. Gold standard VCDRs were measured from monoscopic photographic slides obtained using the Zeiss camera by a fourth ophthalmologist. RESULTS Measurement of agreement (Kappa values) between estimated VCDR of digital images and photographs by the three ophthalmologists were 0.52, 0.38, and 0.50 respectively. Agreement between gold standard and estimated VCDR from photographs were 0.87, 0.45, and 0.84 respectively (specificity between 79% and 97%, sensitivity between 70% and 95%). Kappa values obtained between gold standard and estimated VCDR from digital images were 0.52, 0.49, and 0.49, respectively (specificity between 68% and 79%, sensitivity between 67% and 87%. CONCLUSION Moderate to good agreement indicates that the digital images from the portable fundus camera may be suitable for optic disk assessment in the current configuration. This easy to use Nidek hand-held camera could be a viable instrument for teleophthalmology if a better digitizing system is incorporated to improve the quality of the images.

Smartphone hearing screening with integrated quality control and data management

Abstract Objective: To determine if a smartphone application could be used as a calibrated screening audiometer with real-time noise monitoring for school screening using automated test sequences. Design: The investigation comprised three studies. Study 1 evaluated calibration accuracy across four Samsung S5301 smartphones (Android v4.0.4) using commercial Sennheiser HD202 headphones. Study 2 involved referencing smartphone microphone sensitivity to narrowband noise intensity as measured in octave bands by a sound-level meter between 30 and 75 dB SPL (5 dB increments). Study 3 compared screening outcomes of smartphone based and conventional hearing screening. Study sample: Study 2: 15 normal-hearing subjects (age range, 18–22 years; all female). Study 3: 162 children (324 ears) aged 5 to 7 years. Results: Smartphone calibration at 20, 30, and 40 dB was within 1 dB of recommended reference equivalent thresholds levels. Microphone calibration for noise monitoring had maximum variability across phones of 0.9, 0.6, and 2.9 dB at 1, 2, and 4 kHz, respectively, from reference intensities (30 to 75 dB SPL). Screening outcomes demonstrated no significant difference between smartphone and conventional audiometry with an overall referral rate of 4.3% and 3.7%, respectively. Conclusions: The newly developed smartphone application can be accurately calibrated for audiometry with valid real-time noise monitoring, and clinical results are comparable to conventional screening.

The relationship between hearing impairment and cognitive function: a meta-analysis in adults

Hearing loss affects over 1.23 billion people globally. It has been proposed that hearing impairment negatively impacts on cognition. Some studies have demonstrated a faster rate of decline in cognition, and increased risk of incident all‐cause dementia. This finding is not ubiquitous. This study used meta‐analysis to examine the evidence‐base regarding the relationship between hearing and cognition.

Clinical validity of hearScreen™ smartphone hearing screening for school children

Objectives: The study aimed to determine the validity of a smartphone hearing screening technology (hearScreen™) compared with conventional screening audiometry in terms of (1) sensitivity and specificity, (2) referral rate, and (3) test time. Design: One thousand and seventy school-age children in grades 1 to 3 (8 ± 1.1 average years) were recruited from five public schools. Children were screened twice, once using conventional audiometry and once with the smartphone hearing screening. Screening was conducted in a counterbalanced sequence, alternating initial screen between conventional or smartphone hearing screening. Results: No statistically significant difference in performance between techniques was noted, with smartphone screening demonstrating equivalent sensitivity (75.0%) and specificity (98.5%) to conventional screening audiometry. While referral rates were lower with the smartphone screening (3.2 vs. 4.6%), it was not significantly different (p > 0.05). Smartphone screening (hearScreen™) was 12.3% faster than conventional screening. Conclusion: Smartphone hearing screening using the hearScreen™ application is accurate and time efficient.