Comparison of the Humphrey swedish interactive thresholding algorithm (SITA) and full threshold strategies

PURPOSE: To compare the Swedish interactive thresholding algorithm (SITA) strategy with the full threshold strategy in routine clinical practice. METHODS: Using the Humphrey visual field analyzer model 750 (Allergan Humphrey, San Leandro, CA), 108 subjects were tested with 24-2 SITA (version A9) and 24-2 full threshold strategies. Test results were compared for time taken and reliability and on the basis of seven criteria of abnormality. RESULTS: The SITA required on average 48.8% less time than the full threshold strategy. Patient reliability parameters were somewhat better with SITA. There was a strong correlation between mean deviation and pattern standard deviation. Average threshold sensitivity at each point was increased by 1.31 dB with SITA, but greater differences were seen at points with lower sensitivity. Using the full threshold strategy as our standard for comparison, the sensitivity of SITA varied from 83.0% to 93.2% in detecting the variously defined abnormalities. Fields shown as normal with full threshold strategy corresponded with those found to be normal with SITA in 79.0 to 96.3% cases depending on criteria for abnormality. There were a few cases in which SITA suggested an early abnormality but results of full threshold testing remained normal. On average, the size and depth of scotomas decreased slightly with SITA, but this difference was not statistically significant. Of the 70 patients surveyed about their preference, 65 (92.9%) preferred SITA. CONCLUSION: Full threshold and SITA strategies are comparable in detecting glaucomatous defects. The SITA strategy requires significantly less time to perform and is a satisfactory alternative to full threshold algorithms in clinical practice for diagnosis and management of glaucoma.     

Objective VEP perimetry in glaucoma: asymmetry analysis to identify early deficits

PURPOSE: The multifocal visual evoked potential (VEP) shows markedly symmetrical responses between the two eyes of control subjects. Patients with glaucoma and patients considered at high risk for glaucoma were examined to determine if VEP asymmetry could be identified and used for diagnosis and detection of early damage. METHODS: Multifocal pattern VEP recordings were performed using a single channel bipolar occipital electrode position and the Visual Evoked Response Imaging System (VERIS). There were 125 subjects: 24 control subjects, 70 patients with glaucoma, and 31 patients considered at high risk for glaucoma. A between-eye relative asymmetry coefficient (RAC) was determined for each of the 60 test points in the VEP field. The RAC for patients with glaucoma and patients considered at risk for glaucoma were compared with values from control subjects. Correlation between Humphrey thresholds and RAC scores was performed. RESULTS: Patients with glaucoma and patients considered at risk for glaucoma both showed significantly larger mean quadrant RAC values. When point by point analysis was performed, 69 out of 70 scotomas were identified with a cluster of at least 3 points of P < 0.05. For those considered at high risk for glaucoma, 10 out of 31 patients had abnormal areas in the VEP field. There was a strong correlation (r = 0.82) between quadrantic RAC mean values and Humphrey quadrant threshold scores in an asymmetric glaucoma subgroup. Abnormal VEP responses were identified in parts of the visual field that were still normal on perimetry. CONCLUSIONS: Asymmetry analysis correctly identifies patients with glaucomatous field loss and shows abnormalities in many patients considered at high risk for glaucoma who still have normal fields. Asymmetry analysis is able to identify objectively the extent of glaucomatous damage and may be able to detect changes before subjective field loss occurs.     

A comparison of short wavelength automated perimetry with frequency doubling perimetry for the early detection of visual field loss in ocular hypertension

Background : Achromatic automated perimetry (AAP) is limited in its ability to detect very early visual field loss in ocular hypertensive patients. Tests targeting axons that are selectively damaged, or have low redundancy, may detect visual field losses before they are seen on AAP. It has been claimed that short wavelength automated perimetry (SWAP) and frequency doubling perimetry (FDP) are two tests that provide early detection. Methods : Patients (n = 62) were selected on the basis that they had raised intraocular pressure but normal visual fields detected by AAP. A SWAP and an FDP was performed on each of the patients and the results compared. Fields were scored as either normal or abnormal based on criteria used in previous studies. Results : On comparing FDP with SWAP as the ‘gold standard’, a sensitivity of 88.9% and a specificity of 96.2% was found, showing a high concordance between the two tests. Conclusion : These results suggest that as SWAP may be predictive of AAP visual field loss, FDP may be similarly predictive.     

Basic biology and clinical impact of immunosenescence.

Immunosenescence is an age-associated decline of immunity involving multiorgan changes. As the mean age of the population increases, an increase of diverse pathologies associated with immunosenescence has been observed in the developed countries. Age-related changes in the immune system contribute to the increased incidence and severity of infectious diseases and possibly cancer in the elderly. Moreover, in young individuals chronic activation of the immune system (as occurs in autoimmune diseases, cancer, HIV infection and other chronic infections) induces changes in the immune response that parallel those observed in elderly individuals. An interdisciplinary approach to immunosenescence including investigation of the molecular and cellular mechanisms and clinical aspects is being utilised by the EU program "Immunology and Ageing in Europe" (ImAginE, QLK6-CT-1999-02031), the second major international conference of which took place in Córdoba, Spain, 22-26th March, 2001). We briefly summarise some of the highlights of the meeting here, and bring together in this special issue a collection of peer-reviewed papers reflecting the broad approach to immunosenescence currently being applied.     

Role of Helicobacter pylori in gastric carcinogenesis

Peptic ulcers and gastric malignancies are the two major complication of the course of Helicobacter pylori-associated chronic gastritis. Both gastric adenocarcinomas and MALT lymphomas occur in association with H. pylori infection, and studies support an etiological association. This article discusses the natural history of H. pylori-related gastric carcinogenesis and criteria to identify people susceptible to H. pylori infection-associated gastric cancer. It then reviews the molecular and genetic mechanisms underlying the malignant transformation of the gastric mucosa associated with H. pylori.     

Hip displacement in spastic cerebral palsy: repeatability of radiologic measurement

Radiologic measures of migration percentage (MP) and acetabular index (AI) taken from plain radiographs of the pelvis are the most commonly used tools for determining hip displacement and management options in children with cerebral palsy and spastic hip disease. This study determined interrater and intrarater reliability of MP and AI on pelvic radiographs chosen to represent a wide range of age (11 months to 8 years 5 months), MP (0%-56%), and AI (9 degrees -33 degrees ). The study demonstrated that an experienced rater would be expected to measure MP on a single radiograph to within +/-5.8% of the true value and a change in MP between two radiographs taken at different times to within +/-8.3% of the true value. Similarly for AI, the measurement error for a typical rater would be within +/-2.6 degrees on a single reading and +/-3.7 degrees if recording change between two occasions. The authors believe that the results indicating true change are acceptable in clinical practice, provided treatment decisions are based on a series of radiographs taken at 6-month intervals, methods and training are standardized, and consistent raters are used.     

Identification of rehabilitation problems after head injury

We have reported a large study of patients admitted to hospital following head injury in the city of Glasgow over one calendar year. This showed 1000 patients still to be disabled one year after their injury. In order to see whether the difficulties reported by these patients represented needs for rehabilitation services, we undertook a parallel study in which a separate group of 26 patients were assessed by the same methods as in the main group, but also had a clinical review by an experienced rehabilitation medicine physician, to determine the patient's rehabilitation needs. The physician was unaware of the results of the first assessment.

Both the extent and the nature of the services as needed were reported remarkably similarly by each form of assessment. In addition, the Glasgow Outcome Scale categories were closely related to the need for services.

We conclude that the data reported by Thornhill et al. can be used to estimate the volume and type of rehabilitation services required by head injured patients in the early months after injury.     

The efficacy of the Pavlik harness,the Craig splint and the von Rosen splint in the management of neonatal dysplasia of the hip. A comparative study

We have reviewed the outcome of 134 hips in 96 children with Graf type-III or type-IV dysplasia of the hip on ultrasound examination. We treated 28 affected hips in 22 children with the Craig splint, 43 hips in 30 children with the Pavlik harness, and 26 hips in 16 children with the von Rosen splint. A total of 37 affected hips in 28 children was not splinted. All children were less than three months of age at referral. Those treated with the von Rosen splint had a significantly better ultrasound appearance at 12 to 20 weeks of age and fewer radiological abnormalities than those not splinted or treated with the Pavlik harness. In the von Rosen group no hip required further treatment with an abduction plaster or operation compared with ten in the Pavlik harness group, three in the Craig splint group and eight in the group without splintage. Our results suggest that the von Rosen splint is more likely to improve the outcome of neonatal dysplasia of the hip and a definitive, large-scale randomised trial is therefore indicated.     

Angelchik Prosthesis Revisited

There are few long-term follow-up reports of the Angelchik prosthesis (AP). We report the longest follow-up series (66-192 months, average 145 months) to date. Between October 1983 and January 1994, 65 patients (45 men and 20 women) aged between 29 and 84 years (mean 52 years) had an AP inserted for gastro-oesophageal reflux (GOR) with or without hiatus hernia (HH). Clinical, radiological, endoscopy, and operative details were reviewed. Postoperative complications, investigations, and follow-up details were critically analyzed. All living patients (n = 53) with an AP in situ were interviewed and symptomatic assessment was carried out using a modified Visick system (I-IV). The average duration of the GOR symptoms before the operation was 5.7 years (range 10 months to 20 years). The average hospital stay was 8 days (range 5-15 days). Postoperatively, five patients developed chest infection/atelectasis, four had superficial wound infection, two had deep vein thrombosis (one with pulmonary embolism), one had urinary retention, and four developed an incisional hernia. Six patients (three with an AP in situ) died of other medical conditions. Ten (15%) patients had removal of the prosthesis. Eight (12%) and 11 (17%) had transient and persistent dysphagia, respectively. Thirteen (20%) and five (8%) patients had distal slippage and proximal migration of the prosthesis, respectively. One patient had erosion of the AP into the stomach, while in another patient, the straps of the prosthesis ruptured. Of the 53 living patients with an AP in situ, 28 (53%) were Visick I, 11 (20%) were Visick II, 11 (20%) were Visick III, and 3 (7%) were Visick IV. We conclude that the AP has poor long-term results, with only 66% attaining Visick I and II, and a prosthesis removal rate of 15% (10/65). Patients with preoperative dysphagia, hypothyroidism, and diabetes tend to do worse with an AP. Obese patients and those with failed previous fundoplication seemed to fare well with an AP. In view of poor long-term results and high incidence of complications as compared to other conventional operations for GOR, we cannot recommend the continued use of the AP.