Joseph M. Chen

SciNet: Lessons Learned from Building a Power-efficient Top-20 System and Data Centre

SciNet, one of seven regional HPC consortia operating under the Compute Canada umbrella, runs Canadas first and third fastest computers (as of June 2010) in a state-of-the-art, highly energy-efficient datacentre with a Power Usage Effectiveness (PUE) design-point of 1.16. Power efficiency, computational bang for the buck and system capability for a handful of flagship science projects were important criteria in choosing the nature of the computers and the data centre itself. Here we outline some of the lessons learned in putting together the systems and the data centre that hosts Canadas fastest computer to date.

Combined Corticosteroid and Antiviral Treatment for Bell Palsy: A Systematic Review and Meta-analysis

CONTEXT New evidence has emerged regarding the use of corticosteroids and antiviral agents in Bell palsy. OBJECTIVE To estimate the association of corticosteroids and antiviral agents with the risk of unsatisfactory facial recovery in patients with Bell palsy. DATA SOURCES The search included MEDLINE, EMBASE, CENTRAL, PsychInfo, CINAHL, Web of Science, PAPERSFIRST, PROCEEDINGSFIRST, and PROQUEST to identify studies up to March 1, 2009. STUDY SELECTION AND DATA EXTRACTION Eligible studies were randomized controlled trials comparing treatment with either corticosteroids or antiviral agents with a control and measuring at least 1 of the following outcomes: unsatisfactory facial recovery (> or = 4 months), unsatisfactory short-term recovery (6 weeks to < 4 months), synkinesis and autonomic dysfunction, or adverse effects. Two reviewers extracted data on study characteristics, methods, and outcomes. Disagreement was resolved by consensus. RESULTS Eighteen trials involving 2786 patients were eligible. Regression analysis identified a synergistic effect when corticosteroids and antiviral agents were administered in combination compared with alone (odds ratio for interaction term, 0.54 [95% confidence interval {CI}, 0.35-0.83]; P = .004). Meta-analysis using a random-effects model showed corticosteroids alone were associated with a reduced risk of unsatisfactory recovery (relative risk [RR], 0.69 [95% CI, 0.55-0.87]; P = .001) (number needed to treat to benefit 1 person, 11 [95% CI, 8-25]), a reduced risk of synkinesis and autonomic dysfunction (RR, 0.48 [95% CI, 0.36-0.65]; P < .001) (number needed to treat to benefit 1 person, 7 [95% CI, 6-10]), and no increase in adverse effects. Antiviral agents alone were not associated with a reduced risk of unsatisfactory recovery (RR, 1.14 [95% CI, 0.80-1.62]; P = .48). When combined with antiviral agents, corticosteroids were associated with greater benefit (RR, 0.48 [95% CI, 0.29-0.79]; P = .004) than antiviral agents alone. When combined with corticosteroids, antiviral agents were associated with greater risk reduction of borderline significance compared with corticosteroids alone (RR, 0.75 [95% CI, 0.56-1.00]; P = .05). CONCLUSIONS In Bell palsy, corticosteroids are associated with a reduced risk of unsatisfactory recovery. Antiviral agents, when administered with corticosteroids, may be associated with additional benefit.

Intratympanic Gentamicin for the Treatment of Unilateral Meniere's Disease†

Objective To determine the efficacy of intratympanic gentamicin instillation as treatment of incapacitating unilateral Menieres disease, using a predetermined regimen with a fixed dose.

Intratemporal facial nerve schwannoma: a management dilemma.

Objective: To report the findings in patients with facial nerve schwannoma in whom surgery was elected at onset versus patients treated expectantly. Study Design: Retrospective case review. Setting: Tertiary referral center. Patients: Twenty-four patients with a mean age of 44 years (range, 18-65 yr) were followed for an average of 6 years (range, 1-19 yr). Intervention: Eleven patients underwent complete tumor excision and 13 patients were enrolled in ongoing monitoring only. Main Outcome Measures: Facial nerve function and hearing acuity were noted at the time of initial and last visits. Magnetic resonance imaging was used to determine tumor growth in those individuals treated expectantly and as a means of excluding tumor recurrence/persistence in those treated surgically. Results: Of the 11 patients who underwent tumor removal, the facial nerve was spared in 7. Eight had varying degrees of facial nerve dysfunction initially. In this group (mean follow-up, 8 yr), six patients had unchanged nerve function, four had improved nerve function, and one had worsened. No long-term recurrence was noted. Of the 13 patients followed expectantly, three had facial weakness initially. During the follow-up interval (mean, 5 yr), facial function remained unchanged for eight and worsened in five. During this interval, 4 of the 13 patients demonstrated tumor growth and 3 have recently undergone tumor removal. Conclusion: Facial nerve schwannomas are extremely slow growing and frequently present without facial dysfunction. It is possible to surgically remove these tumors while sparing the nerve; as a result, postoperative function is correspondingly better. Finally, the decision on how to treat these patients should be individualized and based on initial facial function, growth rate, surgical experience, and informed patient consent.

Early-deafened adult cochlear implant users: assessment of outcomes.

OBJECTIVE To determine whether adults deafened in the prelingual and perilingual stages of speech development realize objective and subjective benefits from cochlear implantation. METHOD Retrospective analysis of the open-set speech recognition and subjective data such as use and quality of life. RESULTS Between 1989 and 1999, 198 deafened adults underwent cochlear implantation at Sunnybrook and Womens College Health Sciences Centre. Of these, 44 patients were deafened pre- or perilingually. These subjects were implanted with a Nucleus 22, Nucleus 24 (Cochlear Corporation, Denver, Colorado, USA), or Clarion (Advanced Bionics Corporation, Sylmar, California, USA) device. The average age at implantation was 34 years (range 14-62 years). Significant differences in speech perception, as measured by a composite score of open-set word, phoneme, and sentence recognition, were found among groups who differed by type of education and communication training received in childhood. CONCLUSION By and large, open-set speech recognition in prelingually and perilingually deafened adults is inferior to that achieved in postlingually deafened adults and varies according to the type of communication training they received. However, cochlear implants have significantly improved the overall communication skills and quality of life in all subgroups of patients.

Management of single-sided deafness with the bone-anchored hearing aid

Objectives: The benefits of the bone-anchored hearing aid (BAHA) for rehabilitation of conductive and mixed hearing loss are well established. Recently, the BAHA was used to rehabilitate patients with single-sided deafness (SSD). In this study, the benefits of the BAHA in SSD are presented. Study Design: Case series with planned data collection. Setting: Tertiary referral center. Subjects and Methods: Twenty-one consecutive adult patients with SSD underwent single-stage BAHA implantation on the side of deafness. Testing in sound field was performed using the hearing-in-noise test (HINT) in both unaided and aided conditions. Speech and noise signals were delivered through two speakers oriented in two test paradigms. The outcomes were expressed as signal-to-noise (S/N) ratios. Subjective benefit analyses were determined through two questionnaires: the Abbreviated Profile of Hearing Aid Benefit (APHAB) and the Glasgow Hearing Aid Benefit Profile (GHABP). Results: All subjects demonstrated significant improvement in speech reception thresholds with the HINT using the BAHA, especially with the 90/270 speaker paradigm, in which the mean improvement over the unaided condition was 5.5 dB SPL (range, 2.0-11.0 dB; P = 0.00001). Qualitative subjective outcome measures demonstrated additional benefits. Conclusion: In SSD patients, the BAHA provides significant subjective benefits and improves speech understanding in noise.

Unilateral Acoustic Neuromas: Long-Term Hearing Results in Patients Managed with Fractionated Stereotactic Radiotherapy, Hearing Preservation Surgery, and Expectantly

Introduction: Hearing preservation is invariably a consideration when exploring treatment options for acoustic neuromas. We reviewed the long‐term hearing results of patients who were treated using 1) hyperfractionated stereotactic radiotherapy (HSR), 2) hearing preservation tumor excision surgery (HPTES), and 3) expectantly (no treatment).

A Comparison of Postcochlear Implantation Speech Scores in an Adult Population

Objectives: The vast majority of cochlear implant recipients realize significant improvement in speech perception. However, there continue to be a small group that does not realize such a benefit. In an effort to identify possible predictors for this, we have compared pre‐ and postimplant audiologic data using Hearing In Noise Test (HINT), City University of New York (CUNY), or Central Institute for the Deaf (CID) scores for 445 consecutive English‐speaking adult patients followed for a minimum of 1 year postimplantation in two distinct groups, poor versus excellent performers.

Benefits of cochlear implantation in early-deafened adults: the Toronto experience.

OBJECTIVE To present the results of a survey administered to a group of early-deafened cochlear implants adults and to report the level of perceived benefit. DESIGN Prospective. SETTING Large tertiary referral centre. METHOD A 47-item questionnaire designed to evaluate cochlear implant use and benefit was sent to 42 early-deafened adult cochlear implant users. The questionnaire can be divided into seven subcategories: time of use, associated symptoms, communication, employment status and function, socialization, perceived benefit, and the impact on quality of life. Responses from 30 patients were received. RESULTS The majority of our patients use their cochlear implant all of their waking hours. The majority of patients continue to depend on lip-reading and hearing as their main mode of communication, although they reported improved lip-reading skills with their cochlear implant. Twenty-three patients (76.7%) were employed. Eleven patients had a change in employment subsequent to cochlear implantation, nine (81.8%) of whom attributed this to their cochlear implant. Our patients als reported greater independence, a greater sense of safety in their environment, and an improved social life. Twenty-nine patients (96.7%) said that they were satisfied with their implant, 28 (93.3%) said that they would go through the same process again, and 27 (90%) said that they would recommend it to a friend in a similar situation. Twenty-nine patients (96.7%) stated that the cochlear implant has had a positive effect on their quality of life. Family and peer support, prior auditory-verbal therapy, and a positive attitude were the most commonly cited factors in successful cochlear implant use. CONCLUSIONS Early-deafened adult cochlear implant users perceive significant benefit from cochlear implantation. Importantly, family and peer support, prior auditory-verbal therapy, and a positive attitude are considered important factors in maximizing this benefit.

Management of Bell palsy: clinical practice guideline

Bell palsy is an idiopathic weakness or paralysis of the face of peripheral nerve origin, with acute onset. It affects 20–30 persons per 100 000 annually, and 1 in 60 individuals will be affected over the course of their lifetime.[1][1],[2][2] The major cause of Bell palsy is believed to be an