Intra-speaker and inter-speaker variability in speech sound pressure level across repeated readings

The intra- and inter-speaker variability of speech sound pressure level (SPL) has been investigated under repeatability conditions in this work. In a semi-anechoic chamber, speech from 17 individuals was recorded with a sound level meter, a headworn microphone, and a vocal monitoring device. The subjects were asked to read twice and in sequence two phonetically balanced passages. The speech variability has been investigated for mean, equivalent, and mode SPL from each reading and device. The intra-speaker variability has been evaluated by means of the average among individual standard deviations in the four readings and it reached the maximum of 2 dB for mode SPL. For the inter-speaker variability, the experimental standard deviation of individual averaged SPL parameters among the four repeated measures has been calculated, obtaining the highest value of 5.3 dB for mode SPL. Changes in SPL variability have been evaluated with different logging intervals for each device. The influence of speech material has been investigated by the Wilcoxon test on paired lists of descriptive statistics for SPL distribution and equivalent SPL in the repeated readings. The data reported in this study may be considered as a preliminary reference for the investigation of changes in speech SPL over subjects

The Spectrum of NF1 Mutations in Korean Patients with Neurofibromatosis Type 1

Neurofibromatosis type 1 (NF1) is one of the most common autosomal dominant disorders in humans. NF1 is caused by mutations in the NF1 gene which consists of 57 exons and encodes a GTPase activating protein (GAP), neurofibromin. To date, more than 640 different NF1 mutations have been identified and registered in the Human Gene Mutation Database (HGMD). In order to assess the NF1 mutational spectrum in Korean NF1 patients, we screened 23 unrelated Korean NF1 patients for mutations in the coding region and splice sites of the NF1 gene. We have identified 21 distinct NF1 mutations in 22 patients. The mutations included 10 single base substitutions (3 missense and 7 nonsense), 10 splice site mutations, and 1 single base deletion. Eight mutations have been previously identified and thirteen mutations were novel. The mutations are evenly distributed across exon 3 through intron 47 of the NF1 gene and no mutational hot spots were found. This analysis revealed a wide spectrum of NF1 mutations in Korean patients. A genotype-phenotype correlation analysis suggests that there is no clear relationship between specific NF1 mutations and clinical features of the disease

Growth in North American white children with neurofibromatosis 1 (NF1)

OBJECTIVE—To analyse the distributions of and generate growth charts for stature and occipitofrontal circumference (OFC) in neurofibromatosis 1 (NF1) patients.
DESIGN—Cross sectional database survey.
SETTING—The National Neurofibromatosis Foundation International Database (NFDB) includes clinical information on NF1 patients from 14 participating centres in North America.
SUBJECTS—A total of 569 white, North American, NF1 patients, 55% female and 45% male.
MAIN OUTCOME MEASURES—Stature and OFC measurements of NF1 patients were compared to age and sex matched population norms using z score standardisation and centile curves.
RESULTS—The distributions of stature and OFC are shifted and unimodal among NF1 patients; 13% of patients have short stature (⩾2 standard deviations below the population mean) and 24% have macrocephaly (OFC ⩾2 standard deviations above the population mean).
CONCLUSIONS—Alterations of stature and OFC are not limited to NF1 patients with frank short stature or macrocephaly.


Keywords: neurofibromatosis 1; stature; occipitofrontal circumference; macrocephal