John P. Szalai

Bio: John P. Szalai is an academic researcher from University of Toronto. The author has contributed to research in topics: Randomized controlled trial & Dementia. The author has an hindex of 38, co-authored 77 publications receiving 6078 citations. Previous affiliations of John P. Szalai include Women's College, Kolkata & Sunnybrook Health Sciences Centre.

Prediction of probable Alzheimer's disease in memory-impaired patients: A prospective longitudinal study

Abstract: We determined whether a battery of neuropsychological tests could predict who would develop Alzheimer's disease (AD) in a group of 123 memory-impaired nondemented patients. Patients were followed longitudinally for 2 years with a research battery of neuropsychological tests. After 2 years, 29 developed probable AD, and 94 did not develop dementia. We used logistic regression analyses to examine the classification accuracy of subjects' performance at entry to the study on the research battery. The logistic regression model was significant with an accuracy of 89%, sensitivity of 76%, and specificity of 94%. Two tests contributed significantly to this model: the delayed recall from the Rey Auditory Verbal Learning Test and the Mental Control subtest of the Wechsler Memory Scale. These two tests alone produced the same accuracy, sensitivity, and specificity as the larger model. These results demonstrate that probable AD can be predicted with a high degree of accuracy and with a relatively brief battery of neuropsychological tests.

Marked flow-dependence of exhaled nitric oxide using a new technique to exclude nasal nitric oxide.

Abstract: Exhaled nitric oxide (NO) may aid in monitoring pulmonary disease. The single-breath NO profile (subjects with nose clip) was described as a NO peak followed by a plateau (NO(PLAT)). Published exhaled NO values vary greatly, possibly due to contamination with nasal NO and differing respiratory maneuvers. We developed a technique to measure pulmonary NO, without nasal NO, by having the subject maintain a positive expiratory pressure (ensuring vellum closure), and we examined the variation in NO(PLAT) over a range of expiratory flows (4.2 to 1,550 ml/s). NO(PLAT) values rose almost 35-fold (3.2 +/- 1.4 ppb to 110.5 +/- 54.8 ppb) with decreasing flow, described by NO(PLAT) = 208.6795 x (flow rate)(-0.5995). However, NO excretion showed an almost 11-fold rise as flow increased. In summary, we present a simple technique for measuring exhaled NO without contamination by nasal NO. There is a marked flow dependence of exhaled NO concentration and excretion. Exhaled pulmonary NO is best measured at very low flow r...

Medical illness and the risk of suicide in the elderly.

Abstract: Background Suicide is a leading cause of death, and rates are especially high among the elderly. Medical illnesses may predispose to suicide, but few controlled studies have examined the association between specific diseases and suicide. We explored the relationship between treatment for several illnesses and the risk of suicide in elderly patients using a population-based approach. Methods All Ontario residents 66 years or older who committed suicide between January 1, 1992, and December 31, 2000, were identified from provincial coroners' records. Their prescription records during the preceding 6 months were compared with those of living matched controls (1:4) to determine the presence or absence of 17 illnesses potentially associated with suicide. Results During the 9-year study period, we identified 1354 elderly patients who died of suicide. The most common mechanisms involved firearms (28%), hanging (24%), and self-poisoning (21%). Specific illnesses associated with suicide included congestive heart failure (odds ratio [OR], 1.73; 95% confidence interval [CI], 1.33-2.24), chronic obstructive lung disease (OR, 1.62; 95% CI, 1.37-1.92), seizure disorder (OR, 2.95; 95% CI, 1.89-4.61), urinary incontinence (OR, 2.02; 95% CI, 1.29-3.17), anxiety disorders (OR, 4.65; 95% CI, 4.07-5.32), depression (OR, 6.44; 95% CI, 5.45-7.61), psychotic disorders (OR, 5.09; 95% CI, 3.94-6.59), bipolar disorder (OR, 9.20, 95% CI, 4.38-19.33), moderate pain (OR, 1.91; 95% CI, 1.66-2.20), and severe pain (OR, 7.52; 95% CI, 4.93-11.46). Treatment for multiple illnesses was strongly related to a higher risk of suicide. Almost half the patients who committed suicide had visited a physician in the preceding week. Conclusions Many common illnesses are independently associated with an increased risk of suicide in the elderly. The risk is greatly increased among patients with multiple illnesses. These data may help clinicians to identify elderly patients at risk of suicide and open avenues for prevention.

The Sunnybrook Stroke Study A Prospective Study of Depressive Symptoms and Functional Outcome

Abstract: Background and Purpose—To assess the prevalence of depressive symptoms, their clinical correlates, and the effects of depressive symptoms on stroke recovery, a relatively unselected, well-diagnosed cohort of consecutive stroke survivors was followed prospectively. Methods—Consecutive admissions to a regional stroke center who met World Health Organization and National Institute of Neurological Disorders and Stroke criteria for stroke were eligible. Subarachnoid hemorrhage and brain stem strokes were excluded. Patients underwent CT, single-photon emission CT, and standardized neurological and cognitive examinations at entry. At 3 months and 1 year after stroke, depressive symptoms were assessed with the Montgomery Asberg Depression Rating Scale (MADRS) and the Zung Self-Rating Depression Scale (SDS). Functional outcome was measured with the Functional Independence Measure, and handicap was assessed by the Oxford Handicap Scale. Results—We assessed 436 patients at entry (mean±SD age, 74.9±11.6 years). There...

ACC/AHA 2006 Guidelines for the Management of Patients With Valvular Heart Disease

Abstract: PREAMBLE......e4 APPENDIX 1......e121 APPENDIX 2......e122 APPENDIX 3......e124 REFERENCES......e124 It is important that the medical profession play a significant role in critically evaluating the use of diagnostic procedures and therapies as they are introduced in the detection, management,

Mild Cognitive Impairment: Clinical Characterization and Outcome

Abstract: Background Subjects with a mild cognitive impairment (MCI) have a memory impairment beyond that expected for age and education yet are not demented. These subjects are becoming the focus of many prediction studies and early intervention trials. Objective To characterize clinically subjects with MCI cross-sectionally and longitudinally. Design A prospective, longitudinal inception cohort. Setting General community clinic. Participants A sample of 76 consecutively evaluated subjects with MCI were compared with 234 healthy control subjects and 106 patients with mild Alzheimer disease (AD), all from a community setting as part of the Mayo Clinic Alzheimer's Disease Center/Alzheimer's Disease Patient Registry, Rochester, Minn. Main Outcome Measures The 3 groups of individuals were compared on demographic factors and measures of cognitive function including the Mini-Mental State Examination, Wechsler Adult Intelligence Scale–Revised, Wechsler Memory Scale–Revised, Dementia Rating Scale, Free and Cued Selective Reminding Test, and Auditory Verbal Learning Test. Clinical classifications of dementia and AD were determined according to the Diagnostic and Statistical Manual of Mental Disorders, Revised Third Edition and the National Institute of Neurological and Communicative Disorders and Stroke–Alzheimer's Disease and Related Disorders Association criteria, respectively. Results The primary distinction between control subjects and subjects with MCI was in the area of memory, while other cognitive functions were comparable. However, when the subjects with MCI were compared with the patients with very mild AD, memory performance was similar, but patients with AD were more impaired in other cognitive domains as well. Longitudinal performance demonstrated that the subjects with MCI declined at a rate greater than that of the controls but less rapidly than the patients with mild AD. Conclusions Patients who meet the criteria for MCI can be differentiated from healthy control subjects and those with very mild AD. They appear to constitute a clinical entity that can be characterized for treatment interventions.

Mild cognitive impairment as a diagnostic entity

Abstract: The concept of cognitive impairment intervening between normal ageing and very early dementia has been in the literature for many years. Recently, the construct of mild cognitive impairment (MCI) has been proposed to designate an early, but abnormal, state of cognitive impairment. MCI has generated a great deal of research from both clinical and research perspectives. Numerous epidemiological studies have documented the accelerated rate of progression to dementia and Alzheimer's disease (AD) in MCI subjects and certain predictor variables appear valid. However, there has been controversy regarding the precise definition of the concept and its implementation in various clinical settings. Clinical subtypes of MCI have been proposed to broaden the concept and include prodromal forms of a variety of dementias. It is suggested that the diagnosis of MCI can be made in a fashion similar to the clinical diagnoses of dementia and AD. An algorithm is presented to assist the clinician in identifying subjects and subclassifying them into the various types of MCI. By refining the criteria for MCI, clinical trials can be designed with appropriate inclusion and exclusion restrictions to allow for the investigation of therapeutics tailored for specific targets and populations.

Regression Diagnostics: Identifying Influential Data and Sources of Collinearity

Abstract: 1. Introduction and Overview. 2. Detecting Influential Observations and Outliers. 3. Detecting and Assessing Collinearity. 4. Applications and Remedies. 5. Research Issues and Directions for Extensions. Bibliography. Author Index. Subject Index.