Characterization of short root anomaly in a Mexican cohort--hereditary idiopathic root malformation.

OBJECTIVE: The purpose of this study was to systematically characterize individuals with short root anomaly (SRA) without any history of orthodontic treatment. The long-term objective of the study was to improve diagnosis and treatment planning and determine risk factors for developing SRA. SETTING AND SAMPLE POPULATION: Twenty-seven patients including two families and 16 unrelated individuals from (9-48 years) reported to orthodontic and/or dental practitioners within the USA. MATERIALS AND METHODS: Digital panoramic and periapical films were analyzed to document pattern and frequency of SRA-affected teeth. Crown-to-root (CR) ratios of the affected teeth were used to characterize the extent of malformation. Pedigree analysis by inspection was completed for one family to determine pattern of inheritance. RESULTS: Twenty-six of the twenty-seven individuals were of Latino descent, and one was of Filipino descent. Hard tissues including enamel, dentin, pulp chambers and canals, and surrounding soft tissues were normal. We found that 25 of 27 individuals had localized SRA and two Latino individuals had generalized SRA. Teeth were affected bilaterally with maxillary central incisors (~63%) and mandibular second premolars most commonly involved (~33%). Affected teeth had a distinct, similar radiographic appearance; in the generalized cases, there was a more severe affection with larger (~twice) CR ratios. Ninety-four percent of affected individuals did not show a significant difference in the CR ratios at different ages. Pedigree analysis suggests an autosomal dominant inheritance pattern in one family. CONCLUSION: This is the first report to show that SRA occurs more frequently in Latino individuals and has a predilection for anterior teeth. The occurrence of SRA in two families further confirms a hereditary component and supports a distinct nosology and nomenclature, hereditary idiopathic root malformation (HIRM) and warrants further investigation.

Right myocardial bridge on CT coronary angiography.

Myocardial bridging is a condition where the coronary artery traverses through the myocardium. Although it is not an uncommon finding in left anterior descending coronary artery (LAD), recently we came across a very rare case of right coronary artery (RCA) traversing through the right myocardium on CT coronary angiography.

Normal variation in the frequency and location of human auditory cortex landmarks. Heschl's gyrus: where is it?

Interpersonal communication via the auditory modality is fundamental to normal human development. One of the prominent anatomical specializations supporting this communication is the transverse gyrus of Heschl on the superior surface of the temporal lobe. This gyrus frequently appears duplicated, either by a sulcus indenting the crown of an initially single gyrus (common stem), or by a complete posterior duplication. The frequency of these duplications has been reported to be elevated in populations with learning disabilities and genetic anomalies. The significance of this observation is unclear, however, due to conflicting reports of the base rate of duplication and the location of relevant sulcal landmarks. In this study we report the variation in frequency and location of the sulcal boundaries of Heschl's gyrus in volumetric magnetic resonance imaging scans of 105 normal controls aged 5-65. The major results were as follows: (i) duplications were unstable--the frequency of duplication ranged from 20 to 60% depending on distance from the midline; (ii) common stem duplications were more frequent than posterior duplications, particularly in the right hemisphere. Intra- and interindividual instability in sulcal landmarks pose serious obstacles to the attempt to map behavioral function onto the brain. Novel methods for dealing with structural variation are needed to facilitate the development of valid mapping techniques.

Deficits in auditory temporal and spectral resolution in language-impaired children.

Between 3 and 6 per cent of children who are otherwise unimpaired have extreme difficulties producing and understanding spoken language. This disorder is typically labelled specific language impairment. Children diagnosed with specific language impairment often have accompanying reading difficulties (dyslexia), but not all children with reading difficulties have specific language impairment. Some researchers claim that language impairment arises from failures specific to language or cognitive processing. Others hold that language impairment results from a more elemental problem that makes affected children unable to hear the acoustic distinctions among successive brief sounds in speech. Here we report the results of psychophysical tests employing simple tones and noises showing that children with specific language impairment have severe auditory perceptual deficits for brief but not long tones in particular sound contexts. Our data support the view that language difficulties result from problems in auditory perception, and provide further information about the nature of these perceptual problems that should contribute to improving the diagnosis and treatment of language impairment and related disorders.