Can MRI Visual Assessment Differentiate the Variants of Primary-Progressive Aphasia?

BACKGROUND AND PURPOSE: Primary-progressive aphasia is a clinically and pathologically heterogeneous condition. Nonfluent, semantic, and logopenic are the currently recognized clinical variants. The recommendations for the classification of primary-progressive aphasia have advocated variant-specific patterns of atrophy. The aims of the present study were to evaluate the sensitivity and specificity of the proposed imaging criteria and to assess the intra- and interrater reporting agreements. MATERIALS AND METHODS: The cohort comprised 51 patients with a root diagnosis of primary-progressive aphasia, 25 patients with typical Alzheimer disease, and 26 matched control participants. Group-level analysis (voxel-based morphometry) confirmed the proposed atrophy patterns for the 3 syndromes. The individual T1-weighted anatomic images were reported by 3 senior neuroradiologists. RESULTS: We observed a dichotomized pattern of high sensitivity (92%) and specificity (93%) for the proposed atrophy pattern of semantic-variant primary-progressive aphasia and low sensitivity (21% for nonfluent-variant primary-progressive aphasia and 43% for logopenic-variant primary-progressive aphasia) but high specificity (91% for nonfluent-variant primary-progressive aphasia and 95% for logopenic-variant primary-progressive aphasia) in other primary-progressive aphasia variants and Alzheimer disease (sensitivity 43%, specificity 92%). MR imaging was least sensitive for the diagnosis of nonfluent-variant primary-progressive aphasia. Intrarater agreement analysis showed mean κ values above the widely accepted threshold of 0.6 (mean, 0.63 ± 0.16). Pair-wise interobserver agreement outcomes, however, were well below this threshold in 5 of the 6 possible interrater contrasts (mean, 0.41 ± 0.09). CONCLUSIONS: While the group-level results were in precise agreement with the recommendations, semantic-variant primary-progressive aphasia was the only subtype for which the proposed recommendations were both sensitive and specific at an individual level.

Hospitalisation for adverse events related to drug therapy: incidence, avoidability and costs.

OBJECTIVES: To determine the incidence of hospital admissions for adverse events related to drug therapy, and to assess whether these drug-related admissions (DRAs) could have been reasonably prevented. SETTING: A tertiary teaching hospital. DESIGN AND PATIENTS: Prospective assessment of all admissions through the emergency department and resulting in a stay of more than 24 hours during 30 consecutive days in November and December 1994 to determine if the admission was related to drug therapy. Cases of intentional overdose were excluded. MAIN OUTCOME MEASURES: The number, type, causality and avoidability of drug-related admissions. RESULTS: Of 965 admissions, 55 (5.7%) were assessed as being drug-related. Drug-related admissions (DRAs) were designated possibly (38%), probably (46%) or definitely (16%) drug-related; caused by prescribing factors (26%), patient noncompliance (27%) and adverse drug reactions (47%); and classified as definitely (5.5%), possibly (60.0%) and not (34.5%) avoidable. The estimated annual cost to the hospital for all DRAs was $3,496,956 and for unavoidable DRAs was $1,629,494. CONCLUSION: The DRA rate we found lies around the middle of the range of other published rates. Few DRAs were judged definitely avoidable and over one-third were unavoidable. Nevertheless, the largest proportion were judged possibly avoidable. As the drugs identified in this study are clearly needed in the community, efforts to reduce DRAs must concentrate on education, counselling and monitoring of drug therapy.