ORCID Profile
0000-0002-6576-543X
Current Organisation
Australian National University
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Publisher: Wiley
Date: 22-09-2018
DOI: 10.1111/JOCD.12431
Abstract: Acne vulgaris is one of the commonest skin disorders affecting up to 80% of the world population at least during adolescence. Significant psychosocial effects such as depression and poor personality development have been linked with acne, especially in female adolescents. Various causative factors, including cosmetic exposure, have been attributed toward acne. To analyze the association between frequent exposure to cosmetics and severity of acne in adolescent females. A cross-sectional analytical study was performed on 140 girls from three schools in Colombo, Sri Lanka. A self-administered questionnaire was utilized to assess the patterns of cosmetic usage. Grading acne of the participants was performed by the researchers utilizing a standard acne grading scale. The overall prevalence of acne in our study population was 91.4% with a mean acne grade of 3.09. At least one cosmetic type was used by 126 (90%) of the population. A Pearson correlation coefficient (r) value of .452 (P < .001) was obtained between cosmetic exposure and acne grade, which indicates a statistically significant correlation. A chi-square value of 22.875 was obtained at a degree of freedom of 2 (P < .001), enabling us to reject the null hypothesis that there is no significant association between cosmetic usage and acne severity. Our results convey a significant positive association between frequent exposure to cosmetics and severity of acne in adolescent females. Girls of this age group must be made aware that cosmetic usage may be a potential aggravating factor for their facial acne.
Publisher: Cold Spring Harbor Laboratory
Date: 05-11-2022
DOI: 10.1101/2022.11.05.515279
Abstract: Obsessive-Compulsive Disorder (OCD) is a psychiatric condition leading to significant distress and poor quality of life. Successful treatment of OCD is restricted by the limited knowledge about its pathophysiology. This study aimed to investigate the pathophysiology of OCD using electroencephalographic (EEG) event related potentials (ERP), elicited from multiple tasks to characterise disorder-related differences in underlying brain activity across multiple neural processes. ERP data were obtained from 25 OCD patients and 27 age- and sex-matched healthy controls (HC) by recording EEG during Flanker and Go/Nogo tasks. Error-related negativity (ERN) was elicited by the Flanker task, while N200 and P300 were generated using the Go/Nogo task. Primary comparisons of the neural response litudes and the topographical distribution of neural activity were conducted using scalp field differences across all time points and electrodes. Compared to HC, the OCD group showed altered ERP distributions. Contrasting with the previous literature on ERN and N200 topographies in OCD where fronto-central negative voltages were reported, we detected positive voltages. Additionally, the P300 was found to be less negative in the frontal regions. None of these ERP findings were associated with OCD symptom severity. These results indicate that in iduals with OCD show altered frontal neural activity across multiple executive function related processes, supporting the frontal dysfunction theory of OCD. Furthermore, due to the lack of association between altered ERPs and OCD symptom severity, they may be considered potential candidate endophenotypes for OCD.
Publisher: Cambridge University Press (CUP)
Date: 24-04-2023
DOI: 10.1017/S0033291723000843
Abstract: Obsessive–compulsive disorder (OCD) is a psychiatric condition leading to significant distress and poor quality of life. Successful treatment of OCD is restricted by the limited knowledge about its pathophysiology. This study aimed to investigate the pathophysiology of OCD using electroencephalographic (EEG) event-related potentials (ERPs), elicited from multiple tasks to characterise disorder-related differences in underlying brain activity across multiple neural processes. ERP data were obtained from 25 OCD patients and 27 age- and sex-matched healthy controls (HCs) by recording EEG during flanker and go/nogo tasks. Error-related negativity (ERN) was elicited by the flanker task, while N200 and P300 were generated using the go/nogo task. Primary comparisons of the neural response litudes and the topographical distribution of neural activity were conducted using scalp field differences across all time points and electrodes. Compared to HCs, the OCD group showed altered ERP distributions. Contrasting with the previous literature on ERN and N200 topographies in OCD where fronto-central negative voltages were reported, we detected positive voltages. Additionally, the P300 was found to be less negative in the frontal regions. None of these ERP findings were associated with OCD symptom severity. These results indicate that in iduals with OCD show altered frontal neural activity across multiple executive function-related processes, supporting the frontal dysfunction theory of OCD. Furthermore, due to the lack of association between altered ERPs and OCD symptom severity, they may be considered potential candidate endophenotypes for OCD.
Publisher: Cold Spring Harbor Laboratory
Date: 04-10-2022
DOI: 10.1101/2022.10.03.510571
Abstract: Obsessive-Compulsive Disorder (OCD) is a mental health condition causing significant decline in the quality of life of sufferers and the limited knowledge on the pathophysiology hinders successful treatment. The aim of the current study was to examine electroencephalographic (EEG) findings of OCD to broaden our understanding of the disease. Resting-state eyes-closed EEG data was recorded from 25 in iduals with OCD and 27 healthy controls (HC). The 1/f arrhythmic activity was removed prior to computing oscillatory powers of all frequency bands (delta, theta, alpha, beta, gamma). Cluster-based permutation was used for between-group statistical analyses, and comparisons were performed for the 1/f slope and intercept parameters. Functional connectivity (FC) was measured using coherence and debiased weighted phase lag index (d-wPLI), and statistically analysed using the Network Based Statistic method. Compared to HC, the OCD group showed increased oscillatory power in the delta and theta bands in the fronto-temporal and parietal brain regions. However, there were no significant between-group findings in other bands or 1/f parameters. The coherence measure showed significantly reduced FC in the delta band in OCD compared to HC but the d-wPLI analysis showed no significant differences. OCD is associated with raised oscillatory power in slow frequency bands in the fronto-temporal brain regions, which agrees with the previous literature and therefore is a potential biomarker. Although delta coherence was found to be lower in OCD, due to inconsistencies found between measures and the previous literature, further research is required to ascertain definitive conclusions.
Publisher: Elsevier BV
Date: 10-2021
Publisher: IEEE
Date: 12-2014
Publisher: Elsevier BV
Date: 03-2019
DOI: 10.1016/J.JANXDIS.2018.11.001
Abstract: Obsessive-compulsive disorder (OCD) is a chronic disease that causes significant decline in the quality of life of those affected. Due to our limited understanding of the underlying pathophysiology of OCD, successful treatment remains elusive. Although many have studied the pathophysiology of OCD through electroencephalography (EEG), limited attempts have been made to synthesize and interpret their findings. To bridge this gap, we conducted a comprehensive literature review using Medline/PubMed and considered the 65 most relevant studies published before June 2018. The findings are categorised into quantitative EEG, sleep related EEG and event related potentials (ERPs). Increased frontal asymmetry, frontal slowing and an enhancement in the ERP known as error related negativity (ERN) were consistent findings in OCD. However, sleep EEG and other ERP (P3 and N2) findings were inconsistent. Additionally, we analysed the usefulness of ERN as a potential candidate endophenotype. We hypothesize that dysfunctional frontal circuitry and overactive performance monitoring are the major underlying impairments in OCD. Additionally, we conceptualized that defective fronto-striato-thalamic circuitry causing poor cerebral functional connectivity gives rise to the OCD behavioural manifestations. Finally, we have discussed transcranial magnetic stimulation and EEG (TMS-EEG) applications in future research to further our knowledge of the underlying pathophysiology of OCD.
Publisher: Hindawi Limited
Date: 31-08-2023
DOI: 10.1155/2023/9958884
Publisher: Springer Science and Business Media LLC
Date: 03-11-2022
DOI: 10.1007/S12671-022-02009-Z
Abstract: Research into the effects of mindfulness meditation indicates improvements in mental health and cognitive function. Mechanisms underpinning these improvements include increased attentional function and decreased emotional reactivity. These functions are engaged when an in idual reacts to an error. As such, researchers have examined differences in neural activity between mindful and non-mindful groups during tasks that elicit error responses using electroencephalography (EEG). Event-related potentials associated with error-processing are primarily the error-related negativity (ERN) and error positivity (Pe), which occur ~ 0–150 ms and ~ 200–400 ms following an error. This meta-analysis aimed to determine the effects of mindfulness on ERN and Pe litudes. Our literature search revealed 16 studies that examined the ERN (total N = 887, 469 mindfulness, 418 controls) and 12 studies that examined the Pe (total N = 747, 395 mindfulness, 352 controls). Results showed a weak association between mindfulness and more negative ERN litudes at electrode FCz, with inconsequential Bayesian evidence, after the analysis was restricted to studies including healthy participants only ( Q (1) = 4.725, p = 0.030, BF10 = 1.714). The results also provided a preliminary suggestion that mindfulness reduced the Pe litude at electrode Pz ( Q (2) = 8.023, p = 0.018), when studying in iduals that had weeks to years of mindfulness practice (but not less than weeks of mindfulness practice). The results do not provide good evidence that mindfulness meditation affects EEG measures of error processing. However, our findings are limited by heterogeneity and potential biases, and as such should be interpreted with caution. Systematic Review Registration: PROSPERO CRD42021249775.
Publisher: Elsevier BV
Date: 05-2023
Publisher: Elsevier BV
Date: 07-2022
No related grants have been discovered for Prabhavi Perera.