Background: Attention deficit/hyperactivity disorder (ADHD) is a common childhood neuropsychiatric disorder. Autonomic nervous system plays a vital role in attention, self-regulation, emotional stability and social affiliation, which are affected in ADHD. The prefrontal cortex, which is vital for attention, motor control, emotional regulation and higher order autonomic control, is hypofunctional in ADHD. In addition, catecholamine dysregulation is there. Purpose: We hypothesized that there is autonomic dysfunction: reduction in overall heart rate variability (HRV) and sympathovagal imbalance in children with ADHD. Methods: Study criteria were drug-naïve ADHD children who were 7-12 years of age of either gender who fulfilled DSM-IV criteria for ADHD and did not have any associated comorbid psychiatric/neurological/medical disorders. Two hundred and seventy ADHD children were screened out of which only 12 were found eligible and 10 participated. Sample size was 20 (cases = 10, age- and gender-matched healthy controls = 10). Short-term HRV of both time and frequency domains were assessed by recording lead II electrocardiogram after using Tell-Show-Do, a behavior shaping technique. Comparison between groups was done using Mann-Whitney and Wilcoxon test. Demographic variables like age, height, weight and body mass index were similar between groups. Results: Among time domain parameters, SD of all NN intervals, square root of the mean of the sum of squares of differences between adjacent NN intervals and percentage of count of number of pairs of adjacent NN intervals differing by more than 50 ms were reduced in ADHD group with p < 0.05. Among frequency domain parameters, total power was reduced in ADHD group with p < 0.05, high frequency power (HF) was reduced in ADHD group with p < 0.01 and low frequency power to HF ratio was higher in ADHD group with p < 0.01. Conclusion: There is autonomic dysfunction in children with ADHD - reduction in overall HRV with sympathovagal imbalance with sympathetic dominance.
Introduction:In frontotemporal dementia (FTD) and Alzheimer's disease (AD), central autonomic structures get affected early. An insight into autonomic functions in these patients is likely to be of diagnostic importance and thus help in prognosticating and also probably explain unexplained sudden death in some of these patients.Objectives:The objective of this study is to identify autonomic dysfunction prevailing in patients. Then, if there is dysfunction, is the pattern same or different in these two conditions. And if different it will serve as an additional biomarker for specific diagnosis.Patients and Methods:There were 25 patients and 25 controls and six patients and three controls in AD and FTD groups, respectively. The participants who were recruited were assessed for heart rate variability and conventional cardiac autonomic function testing. The parameters were analyzed using LabChart version 7 software and compared with control population using appropriate statistical methods using SPSS version 22 software.Results:The mean overall total power was low in the FTD group (P < 0.001), and there was significant reduction in the standard deviation of normal-to-normal intervals and root mean square of successive differences (P < 0.001) with elevated sympathovagal balance in the FTD group (P = 0.04). Patients with AD also showed sympathetic dominance, but there was in addition parasympathetic suppression unlike in the FTD group.Conclusion:This study reveals autonomic dysfunction in patients with FTD and AD. Both conditions show sympathetic dominance, probably consecutive to the involvement of central autonomic regulatory structures as a shared domain. It remains to be confirmed if these findings are the cause or effect of neurodegeneration and might open up newer territories of research based on the causal role of neurotransmitters in these regions and thus lead to novel therapeutic options such as yoga. The presence of parasympathetic suppression in AD in addition helps differentiate these two conditions.
Objectives:To evaluate the pulmonary function in Guillain–Barre syndrome (GBS) patients in subacute phase and find clinical correlates of pulmonary dysfunction.Methods:This was a single-center, prospective, cross-sectional, hospital-based study in GBS patients performed in Department of Neurological Rehabilitation at a tertiary care institute. Clinical examination for pulmonary function was done by measuring chest expansion. The pulmonary function tests were carried out by Spirometry kit Microquark Cosmed, Italy. Fatigue was assessed by Fatigue Severity Scale, disability status by Hughes Disability Scale (HDS), and muscle weakness by Medical Research Council sum scores.Statistical Analysis:Statistical analysis was performed by Stata 11. The significance of P value was adjudged against an alpha of 0.05.Results:Twenty-eight patients were included with 17 (61%) men and mean age of 31 years. Median duration of symptoms was 16.5 days. There were 10 (36%) demyelinating and 18 (64%) axonal variants. Twenty-six (93%) patients scored more than 2 on HDS. All study participants reported fatigue. Twenty-two (78.6%) patients had chest expansion of <2.5 cm. Spirometry showed restrictive pulmonary dysfunction in 23 (79%) patients. Significant correlation was found between abnormal pulmonary function test and chest expansion (P = 0.003).Conclusion:Pulmonary dysfunction in GBS is common even during subacute phase. It needs to be identified and managed appropriately for better clinical outcome.
Objective: To look for evidence of cardiac autonomic dysfunction in patients with Alzheimer's disease (AD).Rationale: Limbic structures are important components of central autonomic control, which undergo degeneration in AD. Acetylcholine is a major neurotransmitter of parasympathetic system and there is cholinergic depletion in AD.Methods: It is a prospective two group comparative study. 25 clinically probable Alzheimer's patients were compared with 25 age and gender matched healthy controls. Short term heart rate variability (HRV), blood pressure variability (BPV) and baroreflex sensitivity (BRS) were assessed. Comparison between the groups was done using Mann-Whitney and Wilcoxon test. Spearman's correlation co-efficient was used to assess correlation between the disease severity and study parameters.Results: In Alzheimer's group, among frequency domain parameters of HRV, high frequency power in normalized units (HF nu) was significantly low (p<0.05): low frequency power in normalized units (LF nu) and LF/HF ratio was significantly high (p<0.05). There was a negative correlation between HF nu and disease severity and a positive correlation between LF nu and LF/HF ratio and disease severity.Discussion: There is a significant reduction in parasympathetic activity with sympathyovagal imbalance with sympathetic dominance in AD. This may be due to central autonomic dysfunction as well as cholinergic depletion. In addition, cardiac autonomic dysfunction and disease severity are positively correlated. Conclusion:There is statistically significant abnormality suggestive of sympathetic predominance and suppression of parasympathetic activity in AD group as compared to control group.
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