Visual Simple Reaction Time in Cyanotic Heart Disease

Abstract

CHILDREN with acquired or congenital cerebral defects accompanied by obvious motor impairment, such as cerebral palsy, have slower performance speed by virtue of their neurologic damage. Prolonged, severe hypoxia of the central nervous system has been shown to lead to profound physiologic and psychologic changes in the organism.1-3 The psychologic effects of mild to moderate degrees of chronic hypoxia are more subtle and difficult to measure and, therefore, present a challenge in diagnosis. One useful index in judging the level of psychomotor performance of subjects is reaction time (RT) measurement.4-7Previous studies on adults at high altitudes and on subjects exposed to oxygen deprivation have shown a correlation between the degree of hypoxia and RT scores.7,8 Members of the High Altitude Expedition to Chile in 1935 had a significantly longer and more variable simple RT when tested at an altitude of 20,140 feet than at sea level. No significant change was noted at lower altitudes. Simi¬ lar results were reported on natives living on mountains at higher altitudes.8 In¬ halation of a 10% mixture of oxygen and nitrogen was shown to slow the RT in normal adults and psychoneurotic pati¬ ents.9

Developmental delay in infants with congenital heart disease

“…Several studies document developmental delay in older children with CHD, especially those with cyanosis [1-3, 5, 9-11] . These investigations support the hypothesis that diminished arterial oxygen saturation may be causally related to slow development, prolonged reaction time, low IQ, and deficits in centrally mediated function [1,9] . Both Isoda [3] and Schlange [10] found in their separate studies of cyanotic and acyanotic patients that the cyanotic patients' mental development was slow and IQs were lower .…”

“…Children with CHD perform less well on a variety of intellectual, perceptual, and psychological tests than do their normal age mates [1,3,5,6,[9][10][11] .…”

“…They noted, however, that when IQ was adjusted for physical incapacity, the differences between cyanotics and acyanotics was reduced . Simple visual reaction time has also been shown to be longer in cyanotic than acyanotic subjects [9] . Moreover, within the cyanotic group, children with lower arterial blood oxygen saturation have lower critical flicker frequency thresholds .…”

Neurocognitive Consequences of Surgically Corrected Congenital Heart Defects: A Review

“…The effects of acyanotic versus cyanotic congenital heart defects has been investigated. Several studies in the 1960s Rosenthal, 1967;Rasof et al, 1967;Feldt et al, 1969;Silbert et al, 1969) found children with cyanotic congenital heart defects to have lower IQ scores and to show inferior performance in gross motor skills, perceptual motor skills, and visual reaction time compared to children with acyanotic congenital heart defects. However, other studies could not confirm these findings (Wray & Sensky, 1999).…”

Intellectual development of infants, children and adolescents with congenital heart disease

“…A number of studies report arterial saturations (sample means and/or ranges) for children undergoing neuropsychological assessments (Aisenberg et al , 1982; Silbert et al , 1969; Rosenthal, 1967; Aisenberg et al , 1977; O'Dougherty, Nuechterlein & Drew, 1984; Wright & Nolan, 1994) but there are few longitudinal studies of oxygen saturation, particularly prior to corrective surgery, to assess whether saturations are chronically low or of intermittent severity and how this might relate to intellectual outcome. However, with the increasing awareness of neurological abnormalities suggestive of hypoxia‐ischaemia in children with CHD, evaluation of cerebral oxygenation prior to cardiac surgery has recently been investigated (Kurth, Steven, Montenegro, Watzman, Gaynor & Spray, 2001).…”