Pulse-synchronous tinnitus and sigmoid sinus wall anomalies: descriptive epidemiology and the idiopathic intracranial hypertension patient population.

OBJECTIVE: Describe the clinical features of a population of patients with sinus wall anomalies (SWA) and pulse-synchronous tinnitus (PST). STUDY DESIGN: Retrospective review. SETTING: Tertiary referral center. PATIENTS: Patients with PST and SWA undergoing surgical management between 2007 and 2012. INTERVENTION: Transmastoid sinus wall reconstruction. MAIN OUTCOME MEASURE: Age, sex, BMI, and postoperative course. Two-tailed t tests (p ≤ 0.05) compared BMI and age of the study group with negative and positive controls. RESULTS: Thirteen patients presented with sigmoid sinus diverticulum (39.4%) and 20 (60.6%) with sinus wall dehiscence. Thirty ears were successfully treated with surgery (responders), and 3 were not (nonresponders). Responders' mean age was 38 years, with 26 female patients (92.9%) and 2 male (7.1%). BMI of responders compared with nonresponders did not differ significantly (35.5 versus 33.4 kg/m2, p = 0.08). BMI of responders was elevated compared with an asymptomatic control group (35.5 versus 27.4 kg/m2, p < 0.0001). BMI of responders did not differ significantly compared with a cohort of patients with spontaneous CSF otorrhea and temporal bone encephaloceles (35.5 versus 40.7 kg/m2, p = 0.17). CONCLUSION: The patients in this study had elevated BMI and were more likely to be female. This patient population strongly resembles that of patients with IIH, suggesting the possibility that SWA may be a cause of PST in some patients with IIH. Illustrative cases supporting this hypothesis are presented.

Visual fields at follow-up in the Ischemic Optic Neuropathy Decompression Trial: evaluation of change in pattern defect and severity over time.

PURPOSE: To evaluate change from baseline to 12 months follow-up in study and nonstudy (fellow) eye visual fields from the Ischemic Optic Neuropathy Decompression Trial (IONDT). DESIGN: Randomized controlled trial and observational study. PARTICIPANTS: The IONDT enrolled patients >or=50 years with acute nonarteritic ischemic optic neuropathy (NAION). Randomized patients (n = 258) had visual acuity 20/64 or refused randomization. INTERVENTIONS: Optic nerve decompression surgery (n = 127) or careful follow-up (n = 131). MAIN OUTCOME MEASURES: We measured visual fields at baseline and at 6 and 12 months follow-up. Using a computerized system, we classified visual field defects by pattern, location, and severity. We examined changes over time by treatment group, age, baseline comorbidities, and change in visual acuity. In fellow (nonstudy) eyes, we assessed change by whether NAION was present at baseline and also incidence of NAION by whether a visual field defect was present at baseline. RESULTS: We analyzed 245 study eye visual field pairs (179 and 66, randomized and nonrandomized, respectively) for change from baseline to 12 months. We observed significant changes in defect distribution within the central field (P = 0.02) for randomized eyes. Superior and inferior altitudinal defects were less severe at follow-up in both randomized and nonrandomized eyes. We observed an association between change in central field severity and change in visual acuity from baseline (P<0.001 at 6 months; P = 0.01 at 12 months; Kendall's tau-b), but no association between visual field change and treatment group, age, or baseline comorbidities. Superior and inferior visual field defects present at baseline in nonstudy eyes improved at follow-up. Fellow (nonstudy) eyes with normal fields did not have an increased risk of developing NAION compared with eyes with >or=1 defects. CONCLUSIONS: Visual fields of NAION patients enrolled in the IONDT were relatively stable from baseline to follow-up. A visual field defect in the nonstudy eye at baseline was not associated with development of NAION during follow-up compared with eyes with normal fields.

Neuron stress and loss following rodent anterior ischemic optic neuropathy in double-reporter transgenic mice.

PURPOSE: Nonarteritic anterior ischemic optic neuropathy (NAION) is an optic nerve infarct involving axons of retinal ganglion cell (RGC) neurons. The rodent NAION model (rAION) can use transgenic mouse strains to reveal unique characteristics about the effects of sudden optic nerve ischemia on RGCs and their axons. The impact of rAION on RGC stress patterns, RGC loss, and their axons after axonal infarct were evaluated. METHODS: A double-transgenic mouse strain was used, containing a construct with cyan fluorescent protein (CFP) under Thy-1 promoter control, and a construct with beta-galactosidase (lacZ) linked to the stress gene c-fos promoter. Thy-1 in the retina is expressed predominantly in RGCs, enabling stereologic analysis of CFP(+) RGC numbers and loss post-rAION-using confocal microscopy. RGC loss was correlated with axonal counts using transmission electron microscopy (TEM). LacZ immunohistochemistry was used to evaluate retinal cell stress after rAION. RESULTS: The 45,000 CFP(+) cells in the RGC layer of control animals compared with previous RGC quantitative estimates. rAION produced RGC stress, defined as lacZ expression, in patterns corresponding with later RGC loss. rAION-associated RGC loss correlated with regional nerve fiber layer loss. Axonal loss correlates with stereologically determined RGC loss estimates in transgenic mice retinas. CONCLUSIONS: Post-ON infarct RGC stress patterns correlate with regional RGC loss. Cellular lacZ levels in most RGCs are low, suggesting rAION-affected RGCs express c-fos only transiently. CFP(+) cell loss correlates closely with quantitative axonal loss, suggesting that the Thy-1 (CFP) transgenic mouse strain is appropriate for RGC stereologic analyses.

Development and validation of a computerized expert system for evaluation of automated visual fields from the Ischemic Optic Neuropathy Decompression Trial.

BACKGROUND: The objective of this report is to describe the methods used to develop and validate a computerized system to analyze Humphrey visual fields obtained from patients with non-arteritic anterior ischemic optic neuropathy (NAION) and enrolled in the Ischemic Optic Neuropathy Decompression Trial (IONDT). The IONDT was a multicenter study that included randomized and non-randomized patients with newly diagnosed NAION in the study eye. At baseline, randomized eyes had visual acuity of 20/64 or worse and non-randomized eyes had visual acuity of better than 20/64 or were associated with patients refusing randomization. Visual fields were measured before treatment using the Humphrey Field Analyzer with the 24-2 program, foveal threshold, and size III stimulus. METHODS: We used visual fields from 189 non-IONDT eyes with NAION to develop the computerized classification system. Six neuro-ophthalmologists ("expert panel") described definitions for visual field patterns defects using 19 visual fields representing a range of pattern defect types. The expert panel then used 120 visual fields, classified using these definitions, to refine the rules, generating revised definitions for 13 visual field pattern defects and 3 levels of severity. These definitions were incorporated into a rule-based computerized classification system run on Excel(R) software. The computerized classification system was used to categorize visual field defects for an additional 95 NAION visual fields, and the expert panel was asked to independently classify the new fields and subsequently whether they agreed with the computer classification. To account for test variability over time, we derived an adjustment factor from the pooled short term fluctuation. We examined change in defects with and without adjustment in visual fields of study participants who demonstrated a visual acuity decrease within 30 days of NAION onset (progressive NAION). RESULTS: Despite an agreed upon set of rules, there was not good agreement among the expert panel when their independent visual classifications were compared. A majority did concur with the computer classification for 91 of 95 visual fields. Remaining classification discrepancies could not be resolved without modifying existing definitions. Without using the adjustment factor, visual fields of 63.6% (14/22) patients with progressive NAION and no central defect, and all (7/7) patients with a paracentral defect, worsened within 30 days of NAION onset. After applying the adjustment factor, the visual fields of the same patients with no initial central defect and 5/7 of the patients with a paracentral defect were seen to worsen. CONCLUSION: The IONDT developed a rule-based computerized system that consistently defines pattern and severity of visual fields of NAION patients for use in a research setting.

Functional and cellular responses in a novel rodent model of anterior ischemic optic neuropathy.

PURPOSE: Anterior ischemic optic neuropathy (AION) is caused by sudden loss of vascular supply to retinal ganglion cell (RGC) axons in the anterior portion of the optic nerve and is a major cause of optic nerve dysfunction. There has been no easily obtainable animal model of this disorder. The current study was conducted to design a novel model of rodent AION (rAION), to enable more detailed study of this disease. METHODS: A novel rodent photoembolic stroke model was developed that is directly analogous to human AION. Using histologic, electrophysiological, molecular- and cell biological methods, the early changes associated with isolated RGC axonal ischemia were characterized. RESULTS: Functional (electrophysiological) changes occurred in RGCs within 1 day after rAION, with a loss of visual evoked potential (VEP) amplitude that persisted in the long term. The retinal gene expression pattern rapidly changed after rAION induction, with an early (<1 day) initial induction of c-Fos mRNA, and loss of RGC-specific gene expression. RGC-specific protein expression declined 2 days after detectable mRNA level changes, and immunostaining suggested that multiple retinal layers react to isolated RGC axonal ischemia. CONCLUSIONS: rAION rapidly results in electrophysiological and histologic changes similar to clinical AION, with reactive responses in primary and supporting neuronal cell layers. The rAION model can enable a detailed analysis of the individual retinal and optic nerve changes that occur after optic nerve stroke, which may be useful in determining possible therapeutic interventions for this disorder.