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Asymmetry Scores (asymmetry + score)

Distribution by Scientific Domains
Medical Sciences66%

Selected Abstracts

A method for quantifying rotational symmetry

NEW PHYTOLOGIST, Issue 4 2007
Frank M. Frey
Summary ,,Here, a new approach for quantifying rotational symmetry based on vector analysis was described and compared with information obtained from a geometric morphometric analysis and a technique based on distance alone. ,,A new method was developed that generates a polygon from the length and angle data of a structure and then quantifies the minimum change necessary to convert that polygon into a regular polygon. This technique yielded an asymmetry score (s) that can range from 0 (perfect symmetry) to 1 (complete asymmetry). Using digital images of Geranium robertianum flowers, this new method was compared with a technique based on lengths alone and with established geometric morphometric methods used to quantify shape variation. ,,Asymmetry scores (s) more clearly described variation in symmetry and were more consistent with a visual assessment of the images than either comparative technique. ,,This procedure is the first to quantify the asymmetry of radial structures accurately, uses easily obtainable measures to calculate the asymmetry score and allows comparisons among individuals and species, even when the comparisons involve structures with different patterns of symmetry. This technique enables the rigorous analysis of polysymmetric structures and provides a foundation for a better understanding of symmetry in nature. [source]

Cleft lip with or without cleft palate and dermatoglyphic asymmetry: evaluation of a Chinese population

ORTHODONTICS & CRANIOFACIAL RESEARCH, Issue 3 2002
K Neiswanger
Structured Abstract Authors , Neiswanger K, Cooper ME, Weinberg SM, Flodman P, Bundens Keglovits A, Liu Y, Hu D-N, Melnick M, Spence MA, Marazita ML Objective , To determine if Chinese individuals with non syndromic cleft lip with or without cleft palate (CL/P) display more dermatoglyphic asymmetry than unaffected relatives or controls. Design , Case , control study with two control groups (genetically related and unrelated). Setting and Sample Population , A total of 500 CL/P probands from Shanghai, China, 421 unaffected relatives, and 66 controls of Chinese heritage. Methods , Finger and palm prints were collected, and pattern frequencies, total ridge counts (TRC), and atd angles were calculated. Asymmetry scores between right and left hands were defined for each of the three dermatoglyphic measures. Probands' asymmetry scores were compared statistically with the scores of unaffected relatives and controls. Results , In general, the probands' asymmetry scores for TRC and atd angle did not differ significantly from the scores of either unaffected relatives or controls. However, probands with a positive family history of clefting showed significantly more asymmetry in their pattern types than either probands without a family history, unaffected relatives or controls. Conclusion , These results suggest that a unique genetic mechanism of developmental instability may obtain in CL/P individuals with a positive family history of clefting. [source]

Asymmetric sphincter innervation is associated with fecal incontinence after anal sphincter trauma during childbirth

NEUROUROLOGY AND URODYNAMICS, Issue 1 2007
Beate M. Wietek
Abstract Aims Functional asymmetry of pelvic floor innervation has been shown to exist in healthy subjects, and has been proposed to be a predictor of increased risk for fecal incontinence in case of trauma. However, this remains to be shown for different clinical conditions such as traumatic childbirth. Methods A conventional surface EMG system was used to assess the innervation of the external anal sphincter. A symmetry index was used to define the relative EMG amplitude asymmetry of the external anal sphincter between 0 (symmetric) and 1 (asymmetric). Three cohorts were studied: 40 nulliparous women in the third trimester (Study 1), 15 primiparous women within 6 months following vaginal delivery without clinically apparent anal sphincter trauma (Study 2), and 50 women after childbirth-related third or fourth degree perineal tear 6,12 months postpartum (Study 3). Furthermore, all women underwent conventional anorectal manometry. Results Sixteen or forty nulliparous women reported signs of fecal incontinence; however, relative asymmetry was not correlated to symptom severity (P,=,0.345), and not to manometric measures (Study 1). In Study 2, Women who had suffered clinically apparent anal sphincter trauma (P,=,0.07) tended to have a stronger association between incontinence and asymmetry. In Study 3, 19/50 women reported moderate to severe incontinence. Asymmetry and symptom severity were significantly correlated (P,<,0.001). Patients with incontinence had a significantly higher asymmetry score than their continent counterparts. Conclusion Functional asymmetry of anal sphincter innervation is significantly associated with incontinence symptoms, but only after childbirth-related sphincter injuries and therefore, should be regarded as an additional risk factor. Neurourol. Urodynam. © 2006 Wiley-Liss, Inc. [source]

A method for quantifying rotational symmetry

NEW PHYTOLOGIST, Issue 4 2007
Frank M. Frey
Summary ,,Here, a new approach for quantifying rotational symmetry based on vector analysis was described and compared with information obtained from a geometric morphometric analysis and a technique based on distance alone. ,,A new method was developed that generates a polygon from the length and angle data of a structure and then quantifies the minimum change necessary to convert that polygon into a regular polygon. This technique yielded an asymmetry score (s) that can range from 0 (perfect symmetry) to 1 (complete asymmetry). Using digital images of Geranium robertianum flowers, this new method was compared with a technique based on lengths alone and with established geometric morphometric methods used to quantify shape variation. ,,Asymmetry scores (s) more clearly described variation in symmetry and were more consistent with a visual assessment of the images than either comparative technique. ,,This procedure is the first to quantify the asymmetry of radial structures accurately, uses easily obtainable measures to calculate the asymmetry score and allows comparisons among individuals and species, even when the comparisons involve structures with different patterns of symmetry. This technique enables the rigorous analysis of polysymmetric structures and provides a foundation for a better understanding of symmetry in nature. [source]

Quantitative EEG Asymmetry Correlates with Clinical Severity in Unilateral Sturge-Weber Syndrome

EPILEPSIA, Issue 1 2007
Laura A. Hatfield
Summary:,Purpose: Sturge-Weber syndrome (SWS) is a neurocutaneous disorder with vascular malformations of the skin, brain, and eye. SWS results in ischemic brain injury, seizures, and neurologic deficits. We hypothesized that a decrease in quantitative EEG (qEEG) power, on the affected side, correlates with clinical severity in subjects with SWS. Methods: Fourteen subjects had 16-channel scalp EEG recordings. Data were analyzed using fast Fourier transform and calculation of power asymmetry. Blinded investigators assigned scores for clinical neurological status and qualitative assessment of MRI and EEG asymmetry. Results: The majority of subjects demonstrated lower total power on the affected side, usually involving all four frequency bands (delta, theta, alpha, and beta). qEEG asymmetry correlated strongly with neurologic clinical severity scores and MRI asymmetry scores. qEEG data generally agreed with the MRI evidence of regional brain involvement. In MRI-qEEG comparisons that did not agree, decreased power on qEEG in a brain region not affected on MRI was more likely to occur in subjects with more severe neurologic deficits. Conclusions: qEEG provides an objective measure of EEG asymmetry that correlates with clinical status and brain asymmetry seen on MRI. These findings support the conclusion that qEEG reflects the degree and extent of brain involvement and dysfunction in SWS. qEEG may potentially be a useful tool for early diagnosis and monitoring of disease progression in SWS. qEEG may prove useful, in severely affected individuals with SWS, for determining regions of brain dysfunction. [source]

Cleft lip with or without cleft palate and dermatoglyphic asymmetry: evaluation of a Chinese population

ORTHODONTICS & CRANIOFACIAL RESEARCH, Issue 3 2002
K Neiswanger
Structured Abstract Authors , Neiswanger K, Cooper ME, Weinberg SM, Flodman P, Bundens Keglovits A, Liu Y, Hu D-N, Melnick M, Spence MA, Marazita ML Objective , To determine if Chinese individuals with non syndromic cleft lip with or without cleft palate (CL/P) display more dermatoglyphic asymmetry than unaffected relatives or controls. Design , Case , control study with two control groups (genetically related and unrelated). Setting and Sample Population , A total of 500 CL/P probands from Shanghai, China, 421 unaffected relatives, and 66 controls of Chinese heritage. Methods , Finger and palm prints were collected, and pattern frequencies, total ridge counts (TRC), and atd angles were calculated. Asymmetry scores between right and left hands were defined for each of the three dermatoglyphic measures. Probands' asymmetry scores were compared statistically with the scores of unaffected relatives and controls. Results , In general, the probands' asymmetry scores for TRC and atd angle did not differ significantly from the scores of either unaffected relatives or controls. However, probands with a positive family history of clefting showed significantly more asymmetry in their pattern types than either probands without a family history, unaffected relatives or controls. Conclusion , These results suggest that a unique genetic mechanism of developmental instability may obtain in CL/P individuals with a positive family history of clefting. [source]