Diabetes Care, Vol 20, Issue 9 1448-1453, Copyright © 1997 by American Diabetes Association
The use of biothesiometry to detect neuropathy in children and adolescents with IDDM
EA Davis, TW Jones, P Walsh and GC Byrne
Department of Diabetes and Endocrinology, Princess Margaret Hospital for Children, Perth, Western Australia. lizdavis@mail.med.upenn.edu
OBJECTIVE: To develop clinically useful reference ranges for vibration
perception thresholds (VPTs), using biothesiometry in children and
adolescents and to assess the reliability of the technique to identify
subclinical neuropathy in subjects with IDDM at this age and to examine a
large population-based sample of pediatric patients. RESEARCH DESIGN AND
METHODS: VPTs were measured using a handheld biothesiometer at the medial
malleolus and hallux in 232 nondiabetic children and adolescents aged 7-18
years (12.9 +/- 4.2 years) and a population-based sample of 307 young IDDM
patients (13.3 +/- 4.6 years of age). The mean of three readings at each
site was correlated with height, pubertal status, and age for all subjects
and, in addition for the IDDM sample, with the duration of IDDM, ambient
blood glucose, and mean HbA1c from diagnosis. Those IDDM subjects found to
have elevated VPTs (> 97th percentile), and a control group of patients
with IDDM underwent nerve conduction studies to determine the sensitivity
and specificity of biothesiometry to detect abnormal neural function in
children. Interoperator reliability was assessed in a separate trial in
which two operators measured VPTs independently in the same 11 children.
RESULTS: In the nondiabetic control subjects, height demonstrated the best
correlation with VPT measures, and a reference range was thus established
with percentile charts, using mean VPT and height. VPTs were higher in the
diabetic sample, compared with the nondiabetic sample (P < 0.05). Of the
children, 28 (9.1%) had VPT values > 97th percentile developed from
studies of the nondiabetic subjects; of these, 11 were younger than 11
years and 8 were prepubertal. Nerve conduction studies confirmed reduced
conduction velocity and prolonged distal latencies in those with abnormal
VPTs, compared with normal control subjects and IDDM patients with normal
VPTs. Sensitivity of biothesiometry to reflect abnormal nerve function was
estimated as 82% and specificity as 75% at this age. Interoperator
variation was small (7.25% of total variance). CONCLUSIONS: Biothesiometry
is a useful noninvasive tool for the detection of subclinical neuropathy in
children and adolescents. The use of height-related reference ranges may
make screening for neuropathy more feasible in younger patients and allow
large-scale longitudiral analysis of its development.