Functional magnetic resonance imaging of cognitive processing in young adults with Down syndrome.

The authors used functional magnetic resonance imaging (fMRI) to investigate neural activation during a semantic-classification/object-recognition task in 13 persons with Down syndrome and 12 typically developing control participants (age range  =  12-26 years). A comparison between groups suggested atypical patterns of brain activation for the individuals with Down syndrome. Correlation analyses between an index of visual spatial ability and brain activation depicted a positive relationship between (a) this index and brain activation in regions of the occipital and parietal lobes for the typically developing individuals and (b) the middle and dorsal frontal gyri in the individuals with Down syndrome. These findings supported the authors' hypothesis that persons with Down syndrome demonstrate atypical neural activation compared with typically developing individuals matched for chronological age.

Coenzyme Q10 (ubiquinol-10) supplementation improves oxidative imbalance in children with trisomy 21.

Endogenous coenzyme Q10 is an essential cofactor in the mitochondrial respiratory chain, a potent antioxidant, and a potential biomarker for systemic oxidative status. Evidence of oxidative stress was reported in individuals with trisomy 21. In this study, 14 children with trisomy 21 had significantly increased (P < 0.0001) plasma ubiquinone-10 (the oxidized component of coenzyme Q10) compared with 12 age- and sex-matched healthy children (historical controls). Also, the mean ratio of ubiquinol-10 (the biochemically reduced component):total coenzyme Q10 was significantly decreased (P < 0.0001). After 3 months of ubiquinol-10 supplementation (10 mg/kg/day) to 10 patients with trisomy 21, the mean ubiquinol-10:total coenzyme Q10 ratio increased significantly (P < 0.0001) above baseline values, and 80% of individual ratios were within normal range. No significant or unexpected adverse effects were reported by participants. To our knowledge, this is the first study to indicate that the pro-oxidant state in plasma of children with trisomy 21, as assessed by ubiquinol-10:total coenzyme Q10 ratio, may be normalized with ubiquinol-10 supplementation. Further studies are needed to determine whether correction of this oxidant imbalance improves clinical outcomes of children with trisomy 21.

Coenzyme Q10 absorption and tolerance in children with Down syndrome: a dose-ranging trial.

Controlled studies of coenzyme Q(10) dosing and tolerance have been reported in adults, but not in pediatric patients. This study compares low- and high-dose coenzyme Q(10) (LiQ-NOL syrup) absorption and tolerance in children with Down syndrome. After a 1-month low-dose (1.0 mg/kg/day) run-in period, all participants received high-dose coenzyme Q(10) (10.0 mg/kg/day) for two additional months (in randomized sequence as one daily dose or split into two daily doses). Chemistry profiles and complete blood counts were determined just before and at the study completion. Plasma coenzyme Q(10) concentrations were determined initially and at each study visit. Parents reported adverse events and study drug evaluations using standardized forms. Most of the 16 children who completed this study tolerated high-dose coenzyme Q(10) well. Uncooperative behavior resulted in premature withdrawal of two participants, and may have been treatment-related. Pre- and posttreatment laboratory test changes were considered to be clinically nonsignificant. Study results indicate that high-dose coenzyme Q(10) (10 mg/kg/day) is well-absorbed and well-tolerated by most children with Down syndrome, and appears to provide plasma concentrations which are comparable to previous adult studies administering much higher coenzyme Q(10) dosages.

Obstructive sleep apnea: Should all children with Down syndrome be tested?

OBJECTIVES: To determine the incidence of obstructive sleep apnea syndrome in children aged 2 to 4 years with Down syndrome and to determine parents' ability to predict sleep abnormalities in this patient population. DESIGN: Prospective cohort study. SETTING: Tertiary care pediatric referral center. PATIENTS: Sixty-five children participating in a 5-year longitudinal study in which the otolaryngologic problems seen in Down syndrome were evaluated. Fifty-six completed overnight polysomnography (PSG) between 4 and 63 months of age (mean age, 42 months). INTERVENTIONS: Overnight PSG was performed. Parents also completed a questionnaire regarding their impressions of their child's sleep patterns before PSG. MAIN OUTCOME MEASURES: Polysomnograms were classified as abnormal if the obstructive index was greater than 1, if the carbon dioxide level was greater than 45 mm Hg for more than two thirds of the study or greater than 50 mm Hg for more than 10% of the study, and/or if there was unexpected hypoxemia less than 92% during sleep or repeated intermittent desaturations less than 90%. We also identified a group of children whose PSGs findings were normal except for an arousal index greater than 10 and were associated with increased work of breathing. RESULTS: The PSGs revealed that 57% of the children had abnormal results and evidence of obstructive sleep apnea syndrome. If we also include an elevated arousal index, 80% of the PSGs had abnormal results. Sixty-nine percent of parents reported no sleep problems in their children, but in this group, 54% of PSGs had abnormal results. Of the parents who reported sleep problems in their children, only 36% had abnormal sleep study results. CONCLUSION: Because of the high incidence of obstructive sleep apnea syndrome in young children with Down syndrome, and the poor correlation between parental impressions of sleep problems and PSG results, baseline PSG is recommended in all children with Down syndrome at age 3 to 4 years.