Study: MRI may show early ADHD onset
MRI may enable physicians to identify children with attention-deficit/hyperactivity disorder (ADHD) before the age of 7, by depicting reductions in regional subcortical brain volumes, offering the potential for early treatment and minimized impact of symptoms on children and adults, according to a study published online June 9 in The Clinical Neuropsychologist.
“Attention-deficit/hyperactivity disorder (ADHD) has become the most commonly diagnosed form of psychopathology in the preschool years, with prevalence estimates in preschoolers ranging from 2 to 8 percent for community studies using strict DSM-IV criteria,” explained E. M. Mahone, PhD, and colleagues from the Kennedy Krieger Institute in Baltimore.
Although ADHD onset does occur in preschool years and has been linked to reduced cortical and subcortical (basal ganglia and cerebellum) volumes, no imaging studies have examined the relationship in children younger than seven years. Because preschool children who develop ADHD are at significant risk for social and academic difficulties, Mahone and co-authors noted, “Earlier identification and treatment of children presenting with attention problems in the preschool years may minimize the harmful impact of ADHD.”
Twenty-six children between the ages of 4 and 5 were imaged with MRI, 13 of whom had ADHD and 13 of whom served as controls. The researchers compared cortical regions and basal ganglia structures between the two groups, with data available for 23 children. The findings were also correlated to behavioral assessments and reports on the participants.
The authors observed significant reductions in subcortical brain volume, specifically the caudate nucleus, among children with ADHD compared to the control group. In addition, left and right caudate volumes were also significantly associated with parent ratings of hyperactive impulsive symptoms.
The two groups showed no significant differences in age, IQ, sex distribution, handedness, race or total cerebral volume.
“This is the first study to directly examine regional cortical and subcortical brain volumes in preschool children presenting with early symptoms of ADHD. Our preliminary results reveal early anomalies (reduced volumes) in the development of the caudate nucleus among preschool children presenting with symptoms of ADHD, and a strong association between bilateral caudate volumes and severity of hyperactive/impulsive (but not inattentive) symptoms,” stated Mahone and colleagues.
The authors noted cortical volumes were less atypical between the ADHD and healthy groups, an example of one potential developmental difference that has been observed in older ADHD patients on MR but may be absent in younger individuals.
Additional studies with larger samples will be important for verifying the findings and shoring up a number of relationships that did not reach significance and/or remained unclear due to the small number of participants.
“Anomalous basal ganglia, particularly caudate, development appears to play an important role among children presenting with early onset symptoms of ADHD,” Mahone and colleagues wrote. “In particular, these preliminary findings suggest that early anomalous caudate development (more than cortical development) is associated with onset of ADHD symptoms in preschoolers.”
“Attention-deficit/hyperactivity disorder (ADHD) has become the most commonly diagnosed form of psychopathology in the preschool years, with prevalence estimates in preschoolers ranging from 2 to 8 percent for community studies using strict DSM-IV criteria,” explained E. M. Mahone, PhD, and colleagues from the Kennedy Krieger Institute in Baltimore.
Although ADHD onset does occur in preschool years and has been linked to reduced cortical and subcortical (basal ganglia and cerebellum) volumes, no imaging studies have examined the relationship in children younger than seven years. Because preschool children who develop ADHD are at significant risk for social and academic difficulties, Mahone and co-authors noted, “Earlier identification and treatment of children presenting with attention problems in the preschool years may minimize the harmful impact of ADHD.”
Twenty-six children between the ages of 4 and 5 were imaged with MRI, 13 of whom had ADHD and 13 of whom served as controls. The researchers compared cortical regions and basal ganglia structures between the two groups, with data available for 23 children. The findings were also correlated to behavioral assessments and reports on the participants.
The authors observed significant reductions in subcortical brain volume, specifically the caudate nucleus, among children with ADHD compared to the control group. In addition, left and right caudate volumes were also significantly associated with parent ratings of hyperactive impulsive symptoms.
The two groups showed no significant differences in age, IQ, sex distribution, handedness, race or total cerebral volume.
“This is the first study to directly examine regional cortical and subcortical brain volumes in preschool children presenting with early symptoms of ADHD. Our preliminary results reveal early anomalies (reduced volumes) in the development of the caudate nucleus among preschool children presenting with symptoms of ADHD, and a strong association between bilateral caudate volumes and severity of hyperactive/impulsive (but not inattentive) symptoms,” stated Mahone and colleagues.
The authors noted cortical volumes were less atypical between the ADHD and healthy groups, an example of one potential developmental difference that has been observed in older ADHD patients on MR but may be absent in younger individuals.
Additional studies with larger samples will be important for verifying the findings and shoring up a number of relationships that did not reach significance and/or remained unclear due to the small number of participants.
“Anomalous basal ganglia, particularly caudate, development appears to play an important role among children presenting with early onset symptoms of ADHD,” Mahone and colleagues wrote. “In particular, these preliminary findings suggest that early anomalous caudate development (more than cortical development) is associated with onset of ADHD symptoms in preschoolers.”