Factors affecting the appearance of 'twin language': An original language naturally developing within twin pairs

<p><b>OBJECTIVES</b>The appearance of 'twin language' has been highlighted as a reason for delayed language development in twins. 'Twin language' is a unique language understandable only within the pair, and not by their mother or others. The purpose of this study was to examine and clarify the factors affecting the appearance of 'twin language'.</p><p><b>METHODS</b>A mailed questionnaires survey was conducted in 2733 mothers of twins. Of them, 1395 mothers returned the questionnaires. The core questionnaire asked for data on birth weight, age at first spoken word, whether the twins were as alike as two peas in a pod, household members and non-verbal play. Logistic regression analysis was used in this study.</p><p><b>RESULTS</b>Out of the 1395 pairs included in this analysis, 598 pairs (42.9%) showed the appearance of a 'twin language'. When the 598 pairs were divided by whether the twin pair was exactly alike or not, there were 112 opposite sex pairs, 105 not-alike male pairs, 106 not-alike female pairs, 129 exactly alike male pairs and 140 exactly alike female pairs. Namely, 38.4% of the opposite sex pairs, 40.4% of the not-alike male pairs, 39.3% of the not-alike female pairs, 47.6% of the exactly alike male pairs and 48.4% in the exactly alike female pairs had a twin language. By multivariate logistic regression analysis controlling for twins' age, it was found that 'twin language' was significantly more frequent in exactly alike twin pairs, pairs with non-verbal play, and pairs with fewer older siblings.</p><p><b>CONCLUSIONS</b>These findings suggest that three factors (whether the twin pair is exactly alike or not, older siblings, non-verbal play) affect the appearance of 'twin language'.</p>

Factors Affecting the Appearance of \lqTwin Language\rq: an Original Language Naturally Developing within Twin Pairs

Objectives: The appearance of ‘twin language’ has been highlighted as a reason for delayed language development in twins. ‘Twin language’ is a unique language understandable only within the pair, and not by their mother or others. The purpose of this study was to examine and clarify the factors affecting the appearance of ‘twin language’. Methods: A mailed questionnaire survey was conducted in 2733 mothers of twins. Of them, 1395 mothers returned the questionnaires. The core questionnaire asked for data on birth weight, age at first spoken word, whether the twins were as alike as two peas in a pod, household members and non-verbal play. Logistic regression analysis was used in this study. Results: Out of the 1395 pairs included in this analysis, 598 pairs (42.9%) showed the appearance of a ‘twin language’. When the 598 pairs were divided by whether the twin pair was exactly alike or not, there were 112 opposite sex pairs, 105 not-alike male pairs, 106 not-alike female pairs, 129 exactly alike male pairs and 140 exactly alike female pairs. Namely, 38.4% of the opposite sex pairs, 40.4% of the not-alike male pairs, 39.3% of the not-alike female pairs, 47.6% of the exactly alike male pairs and 48.4% in the exactly alike female pairs had a twin language. By multivariate logistic regression analysis controlling for twins’ age, it was found that ‘twin language’ was significantly more frequent in exactly alike twin pairs, pairs with non-verbal play, and pairs with fewer older siblings. Conclusions: These findings suggest that three factors (whether the twin pair is exactly alike or not, older siblings, non-verbal play) affect the appearance of ‘twin language’.

Lifestyle, mental health status and salivary secretion rates

The relations between salivary variables, lifestyle and mental health status were investigated for 61 healthy female university students. The salivary secretion rates were significantly higher in the good lifestyle groups compared with the poor lifestyle groups. Among the 8 lifestyle items tested. "eating breakfast" and "mental stress" were significantly related to the salivary secretion rates. The present findings suggest that the acquisition of a good lifestyle is also very important from the viewpoint of the prevention of oral disease.A highly significant correlation (r=0.97; p<0.01) between the salivary cortisol levels and the cortisol secretion rates when controlled for the salivary secretion rates was also observed. This suggests that there is a high correlation between the intact salivary cortisol levels and the total cortisol quantity per unit time. Therefore, both these values can be used as a good index for the salivary cortisol determination.

Daily lifestyles and anti-mutagenicity of saliva

<p><b>OBJECTIVES</b>The purpose of this study was to investigate the relation between lifestyle and the antimutagenicity of saliva.</p><p><b>METHODS</b>Subjects were 52 healthy female university students. The collection of the saliva samples and the lifestyle measurements were carried out for them. The anti-mutagenicity of the saliva was measured using the umu test.</p><p><b>RESULTS</b>With regard to the lifestyle items, only "nutrient balance" tended to contribute positively to the inhibiting capacity of the saliva on the mutagenicity of AF-2. In addition, there was a significant inverse correlation between the score of 7 other items and the inhibiting capacity of the saliva (r=-0.32; p<0.05). We also found a significant relation between their tea and/or coffee consumption and the inhibiting capacity of the saliva.</p><p><b>CONCLUSIONS</b>These findings suggest that the inhibiting capacity of saliva worked to decrease mutagen levels that were enhanced by poor lifestyle. In addition, "nutrient balance" may contribute to the inhibiting capacity of the saliva independent of 7 other items. With regard to the tea and/or coffee consumption. further studies should be carried out.</p>

A further note on the sampling device for the anti-mutagenicity of saliva

<p><b>OBJECTIVES</b>The purpose of this study was to compare the anti-mutagenicity of Salivette and test-tube sampling saliva. In addition, the relation between the inhibiting and pH-buffering capacities of saliva was investigated.</p><p><b>METHODS</b>Subjects were 52 healthy female university students. The collection of saliva samples was carried out using 2 sampling devices; test-tube and Salivette. The anti-mutegenicity of the saliva was measured using the umu test.</p><p><b>RESULTS</b>The inhibiting capacity of Salivette-saliva was significantly lower compared with that of testube-saliva (p<0.01,t test). However, there was a significant correlation between them (r=0.35; p<0.05). In addition, there was a significant correlation between the inhibiting and pH-buffering capacities of saliva (r=-0.36; p<0.05).</p><p><b>CONCLUSIONS</b>These findings suggest that both the Salivette and the test-tube may be appropriate as saliva-sampling devices. In addition, they suggest that the bicarbonates might inhibit the anti-mutagenicity of saliva, or that the activity of substances related to the anti-mutagenicity of saliva might be dependent on pH.</p>

A Further Note on the Sampling Device for the Anti-Mutagenicity of Saliva

Objectives: The purpose of this study was to compare the anti-mutagenicity of Salivette and test-tube sampling saliva. In addition, the relation between the inhibiting and pH-buffering capacities of saliva was investigated. Methods: Subjects were 52 healthy female university students. The collection of saliva samples was carried out using 2 sampling devices; test-tube and Salivette. The anti-mutagenicity of the saliva was measured using the umu test. Results: The inhibiting capacity of Salivette-saliva was significantly lower compared with that of test-tube-saliva (p<0.01, t test). However, there was a significant correlation between them (r=0.35; p<0.05). In addition, there was a significant correlation between the inhibiting and pH-buffering capacities of saliva (r=−0.36; p<0.05). Conclusions: These findings suggest that both the Salivette and the test-tube may be appropriate as saliva-sampling devices. In addition, they suggest that the bicarbonates might inhibit the anti-mutagenicity of saliva, or that the activity of substances related to the anti-mutagenicity of saliva might be dependent on pH.

Daily Lifestyles and Anti-Mutagenicity of Saliva

Objectives: The purpose of this study was to investigate the relation between lifestyle and the anti-mutagenicity of saliva. Methods: Subjects were 52 healthy female university students. The collection of the saliva samples and the lifestyle measurements were carried out for them. The anti-mutagenicity of the saliva was measured using the umu test. Results: With regard to the lifestyle items, only “nutrient balance” tended to contribute positively to the inhibiting capacity of the saliva on the mutagenicity of AF-2. In addition, there was a significant inverse correlation between the score of 7 other items and the inhibiting capacity of the saliva (r=−0.32; p<0.05). We also found a significant relation between their tea and/or coffee consumption and the inhibiting capacity of the saliva. Conclusions: These findings suggest that the inhibiting capacity of saliva worked to decrease mutagen levels that were enhanced by poor lifestyle. In addition, “nutrient balance” may contribute to the inhibiting capacity of the saliva independent of 7 other items. With regard to the tea and/or coffee consumption, further studies should be carried out.

Lifestyle, Mental Health Status and Salivary Secretion Rates

The relations between salivary variables, lifestyle and mental health status were investigated for 61 healthy female university students. The salivary secretion rates were significantly higher in the good lifestyle group compared with the poor lifestyle group. Among the 8 lifestyle items tested, “eating breakfast” and “mental stress” were significantly related to the salivary secretion rates. The present findings suggest that the acquisition of a good lifestyle is also very important from the viewpoint of the prevention of oral disease. A highly significant correlation (r=0.97; p<0.01) between the salivary cortisol levels and the cortisol secretion rates when controlled for the salivary secretion rates was also observed. This suggests that there is a high correlation between the intact salivary cortisol levels and the total cortisol quantity per unit time. Therefore, both these values can be used as a good index for the salivary cortisol determination.