Cognitive Correlates of TCD in Pediatric Sickle Cell

Kral, Mary

Abstract

Sickle cell disease (SCD), a class of genetic disorders characterized by abnormal, sickled red blood cells, affects an estimated 1 in 400 African American newborns annually (Charache, Lubin & Reid, 1989). Although SCD has system-wide effects, among the most debilitating are neurological complications, resulting from progressive cerebrovascular disease (Ohene-Frempong et al., 1998). While the neurocognitive sequelae of clinically apparent cerebrovascular accidents in children with SCD are characterized by pervasive impairments (Armstrong et al., 1996; Cohen et al., 1994; Crafte et al., 1993; 1994; Schatz et al., 1999), sublinical cerebrovascular disease is associated with subtle neurocognitive deficits in attention/concentration and visual-motor speed/coordination (Brown et al., 2000; DeBaun et al., 1998; Steen et al., 1999; Watkins et al., 1998). A recent series of investigations support the reliability of transcranial Doppler (TCD) ultrasonography for the prediction of stroke in pediatric SCD (Adams et al., 1998; 1997; 1994; 1992). The present research represents the first empirical investigation of the relationship between TCD data and neurocognitive deficits in children with SCD. Moreover, this study offers an improvement in design and methodology over previous investigations as TCD offers an opportunity to investigate the progressive nature of cerebrovasculopathy in this population of children. Additionally, the present research will address the utility of TCD diagnostic groupings in terms of neuropsychological functioning, thereby identifying those children at risk for neurological complications and concomitant cognitive impairment.