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This study addressed the question of whether dementia of the Alzheimer type (DAT) produces a breakdown in aspects of the inhibitory component underlying selective attention. Two measures of identity negative priming and 2 measures of distractor interference were obtained. In Experiment 1, participants were presented with overlapping picture stimuli, and in Experiment 2, participants were presented with overlapping written word stimuli. The results of both experiments produced reliable and similar size negative priming in young and old adults, but there was no evidence of negative priming in the individuals with DAT. In contrast, the naming latencies of all 3 groups showed a reliable and similar size distractor interference effect. These results suggest that although the inhibitory component underlying selective attention is impaired in individuals with DAT, the ability to differentiate a target from a distractor may be preserved under certain task conditions.

Previous studies of negative priming have shown that, relative to young adults, old adults can effectively suppress location information associated with stimuli, but not information about the identity of stimuli. S.L. Connelly and L. Hasher (1993) attributed this dissociation to an age-related decrement in the inhibitory processes that suppress meaning-bearing information. In this study, the authors report both identity negative priming and distractor interference in a group of young and old adults. Their results force a reconsideration of an age-related decrement in the inhibitory processes underlying the suppression of meaning-bearing information. The results also suggest that whether a relationship between negative priming and interference is observed may depend on whether the 2 measures index the same level of processing.

Neurogenic heterotopic ossification (NHO) is a disorder of aberrant bone formation affecting one in five patients sustaining a spinal cord injury or traumatic brain injury. Ectopic bone forms around joints in characteristic patterns, causing pain and limiting movement especially around the hip and elbow. Clinical sequelae of neurogenic heterotopic ossification include urinary tract infection, pressure injuries, pneumonia and poor hygiene, making early diagnosis and treatment clinically compelling. However, diagnosis remains difficult with more investigation needed. Our pathophysiological understanding stems from mechanisms of basic bone formation enhanced by evidence of systemic influences from circulating humor factors and perhaps neurological ones. This increasing understanding guides our implementation of current prophylaxis and treatment including the use of non-steroidal anti-inflammatory drugs, bisphosphonates, radiation therapy and surgery and, importantly, should direct future, more effective ones.

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