Krishnamachari Srinivasan

Decreased heart rate variability in panic disorder patients: A study of power-spectral analysis of heart rate

We have previously found decreased standard deviations and mean consecutive differences of R-R intervals in panic disorder patients in standing posture, compared with control subjects. In the present study, we used spectral analysis of heart rate variability to examine autonomic function in 21 panic disorder patients and 21 normal control subjects. Patients had a significantly lower standard deviation of heart rate in supine as well as standing postures. Absolute low frequency power (0.01-0.05 Hz) was also significantly lower in panic disorder patients in standing postures. Upon standing, the panic disorder patients had significantly higher relative mid-frequency power (0.07-0.15 Hz). During a standing deep-breathing condition at six breaths per minute, the patients had a significantly decreased absolute and relative mid-frequency (0.07-0.15 Hz) power compared with control subjects. These findings suggest a decrease in cholinergic and a relative increase in adrenergic responsiveness in panic disorder patients compared with control subjects.

Diminished chaos of heart rate time series in patients with major depression

BACKGROUND Depression and anxiety have been linked to serious cardiovascular events in patients with preexisting cardiac illness. A decrease in cardiac vagal function as suggested by a decrease in heart rate (HR) variability has been linked to sudden death. METHODS We compared LLE and nonlinearity scores of the unfiltered (UF) and filtered time series (very low, low, and high frequency; VLF, LF and HF) of HR between patients with depression (n = 14) and healthy control subjects (n = 18). RESULTS We found significantly lower LLE of the unfiltered series in either posture, and HF series in patients with major depression in supine posture (p <.002). LLE (LF/UF), which may indicate relative sympathetic activity was also significantly higher in supine and standing postures in patients (p <.05); LF/HF (LLE) was also higher in patients (p <.05) in either posture. CONCLUSIONS These findings suggest that major depression is associated with decreased cardiac vagal function and a relative increase in sympathetic function, which may be related to the higher risk of cardiovascular mortality in this group and illustrates the usefulness of nonlinear measures of chaos such as LLE in addition to the commonly used spectral measures.

Increased QT variability in patients with panic disorder and depression

Abstract This study investigated beat-to-beat QT variability in patients with panic disorder and depression, and normal control subjects using an automated algorithm to compute QT intervals. An increase in QT variability appears to be associated with symptomatic patients with dilated cardiomyopathy and also with an increased risk for sudden death. QT vm (QT variability normalized for mean QT interval) and QT vi (a log ratio of QT variance normalized for mean QT over heart rate variability normalized for mean heart rate) were significantly higher in patients with panic disorder and depression in supine as well as standing postures ( P= 0.002 and 0.0001 for QT vm and QT vi , respectively). In another analysis, QT vi was significantly higher in patients with panic disorder compared to control subjects in supine as well as standing postures during spontaneous breathing as well as 12, 15 and 20 per minute breathing ( P= 0.005). These findings are important especially in view of the recent reports of increased risk for cardiovascular mortality and sudden death in patients with anxiety and depression and the utility of QT vi as a noninvasive measure of temporal repolarization lability.

Vitamin B-12 Supplementation during Pregnancy and Early Lactation Increases Maternal, Breast Milk, and Infant Measures of Vitamin B-12 Status

Pregnant women in resource-poor areas are at risk of multiple micronutrient deficiencies, and indicators of low vitamin B-12 status have been associated with adverse pregnancy outcomes, including anemia, low birth weight, and intrauterine growth retardation. To evaluate whether daily oral vitamin B-12 supplementation during pregnancy increases maternal and infant measures of vitamin B-12 status, we performed a randomized, placebo-controlled clinical trial. Pregnant women <14 wk of gestation in Bangalore, India, were randomly assigned to receive daily oral supplementation with vitamin B-12 (50 μg) or placebo through 6 wk postpartum. All women were administered iron and folic acid supplements throughout pregnancy. One hundred eighty-three women were randomly assigned to receive vitamin B-12 and 183 to receive placebo. Compared with placebo recipients, vitamin B-12-supplemented women had significantly higher plasma vitamin B-12 concentrations at both the second (median vitamin B-12 concentration: 216 vs. 111 pmol/L, P < 0.001) and third (median: 184 vs. 105 pmol/L, P < 0.001) trimesters. At 6 wk postpartum, median breast milk vitamin B-12 concentration was 136 pmol/L in vitamin B-12-supplemented women vs. 87 pmol/L in the placebo group (P < 0.0005). Among vitamin B-12-supplemented women, the incidence of delivering an infant with intrauterine growth retardation was 33 of 131 (25%) vs. 43 of 125 (34%) in those administered placebo (P = 0.11). In a subset of infants tested at 6 wk of age, median plasma vitamin B-12 concentration was 199 pmol/L in those born to supplemented women vs. 139 pmol/L in the placebo group (P = 0.01). Infant plasma methylmalonic acid and homocysteine concentrations were significantly lower in the vitamin B-12 group as well. Oral supplementation of urban Indian women with vitamin B-12 throughout pregnancy and early lactation significantly increases vitamin B-12 status of mothers and infants. It is important to determine whether there are correlations between these findings and neurologic and metabolic functions. This trial was registered at clinicaltrials.gov as NCT00641862.

Effect of fortification with multiple micronutrients and n−3 fatty acids on growth and cognitive performance in Indian schoolchildren: the CHAMPION (Children's Health and Mental Performance Influenced by Optimal Nutrition) Study

BACKGROUND Fortification with multiple micronutrients has been shown to improve growth and cognitive performance among children in developing countries, but it is unknown whether higher concentrations are more effective than lower concentrations. OBJECTIVE We compared the effect of 2 different concentrations of a combination of micronutrients and n-3 (omega-3) fatty acids on indicators of growth and cognitive performance in low-income, marginally nourished schoolchildren in Bangalore, India. DESIGN In a 2-by-2 factorial, double-blind, randomized controlled trial, 598 children aged 6-10 y were individually allocated to 1 of 4 intervention groups to receive foods fortified with either 100% or 15% of the Recommended Dietary Allowance of micronutrients in combination with either 900 mg alpha-linolenic acid plus 100 mg docosahexaenoic acid or 140 mg alpha-linolenic acid for 12 mo. Anthropometric and biochemical assessments were performed at baseline and 12 mo. Cognitive performance was measured at baseline and at 6 and 12 mo. RESULTS The high micronutrient treatment significantly improved linear growth at 12 mo (0.19 cm; 0.01, 0.36) and short-term memory at 6 mo (0.11 SD; 0.01, 0.20) and was less beneficial on fluid reasoning at 6 (-0.10 SD; -0.17, -0.03) and 12 (-0.12 SD; -0.20, -0.04) mo than was the low micronutrient treatment, whereas no differences were observed on weight, retrieval ability, cognitive speediness, and overall cognitive performance. No significant differences were found between the n-3 treatments. CONCLUSIONS The high micronutrient treatment was more beneficial for linear growth than was the low micronutrient treatment. However, with some small differential effects, higher micronutrient concentrations were as effective as lower concentrations on cognitive performance. This trial was registered at clinicaltrials.gov as NCT00467909.

Iodine supplementation in pregnancy and its effect on child cognition.

Maternal hypothyroidism and hypothyroxenemia due to iodine deficiency have been shown to affect development of the newborn negatively. Maternal iodine supplementation may therefore improve cognitive performance of the offspring, even in areas of mild-to-moderate iodine deficiency (ID). Several iodine supplementation studies have been performed in mildly ID pregnant women in Europe. These studies have shown that iodine supplementation increases maternal urinary iodine (UI) excretion and reduces thyroid volume, as well as prevents increases in infant thyroid volume and thyroglobuline. However, randomized controlled studies with long-term outcomes are lacking. Therefore, two trials were started in 2008 in areas of low iodine status; one in Bangalore, India (n=325), and another in Bangkok, Thailand (n=514). Pregnant women were recruited <14 weeks gestational age and randomized to either receive a daily dose of 200 μg I (as KI) or an identical placebo throughout pregnancy. Both trials are ongoing, and women are followed up during pregnancy and at delivery. UI, thyroid hormones, and thyroid size are measured. Birth outcomes are recorded, such as gestational age at delivery, height, weight, and APGAR scores, and cord blood and heel stick blood (<72 h) is collected from the child. Child development is assessed at 6 weeks of age using the Neonatal Behavioral Assessment Scale (NBAS), and at 12 and 24 months of age using the Bayley Scales of Infant Development. The outcomes of these trials will contribute importantly to the evidence base for iodine supplementation of pregnant women living in areas of mild iodine deficiency.

Traveling with cognitive tests: testing the validity of a KABC-II adaptation in India.

The authors evaluated the adequacy of an extensive adaptation of the American Kaufman Assessment Battery for Children, second edition (KABC-II), for 6- to 10-year-old Kannada-speaking children of low socioeconomic status in Bangalore, South India. The adapted KABC-II was administered to 598 children. Subtests showed high reliabilities, the Cattell—Horn—Carroll model underlying the original KABC-II was largely replicated, and external relations with demographic characteristics and an achievement measure were consistent with expectations. The subtests showed relatively high loadings on the general cognitive factor, presumably because of the high task novelty and, hence, cognitive complexity of the tests for the children. The findings support the suitability and validity of the KABC-II adaptation. The authors emphasize that test adaptations can only be adequate if they meet both judgmental (qualitative) and statistical (quantitative) adaptation criteria.

Consumption of a mid-morning snack improves memory but not attention in school children

Muthayya, S., T. Thomas, K. Srinivasan, K. Rao, A. V. Kurpad, J.-W. Van Klinken, G. Owen and E.A. de Bruin: Consumption of a mid-morning snack improves memory but not attention in school children. Physiol Behav 00(0) 000-000, 2006.--This study aimed to determine whether consumption of a mid-morning snack with appropriate energy compensation through a smaller breakfast or lunch, resulted in improved cognitive performance of 7-9 year old children with a low and high socioeconomic status (LSES and HSES, n=35 and 34 respectively). The children were each randomly assigned to three iso-caloric dietary interventions: control (standard breakfast, no snack and standard lunch), intervention A (small breakfast, snack, and standard lunch) and intervention B (standard breakfast, snack, and small lunch), using a cross-over design. The children were tested on three different days, each one week apart. Computerised tests of cognitive performance, consisting of memory, sustained attention and psychomotor speed, were performed during four sessions, i.e., prior to breakfast, after breakfast, after a mid-morning snack and after lunch. Having a mid-morning snack resulted in a smaller decline in immediate and delayed memory in LSES but not in HSES children. Having a snack did not influence sustained attention and psychomotor speed in either LSES or HSES children. This study shows that a more evenly distributed energy intake throughout the morning by consuming a mid-morning snack improves memory performance in school-age LSES children even when the total amount of energy consumed during the morning is not altered.

Maternal mental health in pregnancy and child behavior.

Maternal mental health research is a public health priority due to its impact on both maternal and child health. Despite the growing number of empirical studies in this area, particularly from developing countries, there is a paucity of synthetic review articles. Therefore, attempting to synthesize the existing literature in this area seems relevant to appraise the readers of the fields progress and to infer directions for future research. The present review aims to provide an overview of the literature on maternal mental health and its association with birth outcomes and child behavior. Specifically, the literature on mental health during pregnancy and in the postpartum period and its influence on birth outcomes and child behavior have been reviewed. Further, a conceptual and methodological evaluation of the existing literature has been provided to identify gaps in the literature and to suggest directions for future research.

Assessing prenatal depression in the rural developing world: a comparison of two screening measures

Significant levels of prenatal depression are reported from the Indian subcontinent (25–45%). A wide variety of measures have been used to screen for prenatal depression in western research. However, little evidence exists on the use of such measures in the context of the developing world. The objective of this study was to assess the validity of the Edinburgh Postnatal Depression Scale (EPDS) and the Kessler 10 Scale of Psychological Distress (K10) as screening measures for prenatal depression in rural South India. One hundred ninety-four women in their third trimester of pregnancy were assessed at a rural prenatal clinic in Karnataka, South India, using the EPDS, the K10 (scored 0–40) and a structured diagnostic psychiatric interview to establish a DSM-IV diagnosis of depression. Depressed women scored significantly higher on the EPDS and K-10 than controls. A receiver-operating characteristic analyses showed both scales to be good screening instruments for prenatal depression in rural South India at a cut-off of ≥13 on the EPDS (sensitivity = 100%, specificity = 84.90%, and area under the curve = 0.95) and ≥6 on the K10 (sensitivity = 100%, specificity = 81.30%, and area under the curve = 0.95). The EPDS and K10 have thus been shown to have equally good sensitivity and specificity in rural settings in the developing world at a cut-off score of ≥13 and ≥6, respectively. This study demonstrates the validity of the EPDS and K10 in screening pregnant women for depression during their prenatal check-ups.