S H O R T R E P O R T Postural Rearrangement in IDDM Patients With Peripheral Neuropathy PIER GIORGIO GIACOMINI, MD ERNESTO BRUNO, MD GLOVANNA MONTICONE, MD STEFANO DI GIROLAMO, MD ANTONIO MAGRINI, MD LEOLUCA PARISI, MD GUIDO MENZINGER, MD LUIGI UCCIOLI, MD OBJECTIVE — To evaluate the influence of diabetic peripheral neuropathy on postural strategy. RESEARCH DESIGN AND METHODS — Static posturography and nerve conduction velocity were performed in the following age-matched subjects: 10 IDDM patients with periph- eral neuropathy, 23 IDDM patients without peripheral neuropathy, and 21 control subjects. All subjects with signs or symptoms of postural instability were excluded from the study. The following posturographic parameters were drawn: 1) velocity of body sway, expressed as mean velocity and average of the SDs, 2) VFY, the parameter derived from the velocity variance and the anteroposterior mean position of the body (this parameter monitors the postural strategy pur- sued by the subject), and 3) fast Fourier transformation on thex (FFTX) andy (FFTY) planes, spectral analysis of the frequencies of body oscillation on frontal (x) and anteroposterior (y) planes. RESULTS — Mean velocity and its SD were higher in IDDM patients with peripheral neurop- athy than in control subjects and IDDM patients without peripheral neuropathy (P < 0.001). VFY was increased in IDDM patients with peripheral neuropathy versus control subjects and IDDM patients without peripheral neuropathy (P < 0.01). A direct relationship was found between parameters of posturography and some parameters of nerve conduction tests. CONCLUSIONS — Diabetic patients with peripheral neuropathy demonstrate a shift from physiological ankle control to hip postural control as monitored by specific posturography analysis. B ody position in space results from several sensory inputs to the central nervous system and related motor outputs (1). Alterations of these inputs/ outputs can give rise to postural reorgani- zation (2). In a previous report from our group, abnormalities of posture have been documented in IDDM patients with peripheral neuropathy, suggesting a vari- ation of posture-maintaining strategies (3). The variation of postural pattern from ankle to hip strategy has been linked to various physiological and pathological conditions (4,5). These variations can be monitored by specific posturographic evaluations such as velocity mean and its SD, fast Fourier transformation (FFT) on x and v planes, and variance of velocity as a function of the body center of gravity on the anteroposterior axis (VFY) (6). The aim of this study is to evaluate posturography in IDDM patients to dem- onstrate the suspected shift of postural control from ankle to hip strategy in neu- ropathic subjects. RESEARCH DESIGN AND M E T H O D S — The same 54 subjects evaluated in our previous study (3) were enrolled. They were free from any inter- fering neurological or labyrinthine disor- ders, without clinical evidence of postural instability or postural hypotension and From the Departments of Otolaryngology (P.G.G., E.B., S.D.G., A.M.) and Endocrinology and Internal Medicine (G.Mo., G.Me., L.U.), University of Rome "Tor Vergata"; the Department of Neurology (L.P.), University of Rome "La Sapienza"; and the Istituto Dermopatico dell' Immacolata (G.Mo.), Istituto di Ricov- ero e Cura a Carattere Scientifico, Rome, Italy. Address correspondence and reprint requests to Pier Giorgio Giacomini, MD, Department of Otolaryn- gology, University of Rome "Tor Vergata," c/o C.I. Columbus, Via Delia Pineta Sacchetti 506, 00168 Rome, Italy. Received for publication 31 July 1995 and accepted in revised form 9 November 1995. FFT, fast Fourier transformation; VFY, parameter derived from velocity variance and anteroposterior mean position of the body. with correct visual acuity (10/10). Of the subjects, 33 were affected by IDDM, 23 without peripheral neuropathy and 10 with peripheral neuropathy, according to San Antonio Consensus Conference guidelines, namely the presence of both signs and symptoms of peripheral neu- ropathy and pathological results of nerve conduction velocity (7). The remaining 21 were normal age-matched control sub- jects. Table 1 shows the clinical profile of the study population. Static posturography was per- formed on a standard platform (S.Ve.P. Amp laid), according to the method previ- ously published (8). The center of gravity is monitored during the test performed with the patient's eyes open and with them closed. The following parameters were drawn. 1. Velocity of center of gravity sway: this was recorded at 10 Hz fre- quency of acquisition, expressed as mean velocity, which expresses the body sway related to time, and av- erage SD, which quantifies the vari- ations of velocity. This is a more predictable test for the evaluation of the control of postural muscles (9). 2. VFY: in young normal adults, the stance is held by a contraction of posterior leg muscles that counter- balances the natural tendency of the center of gravity to shift forward on the anteroposterior axis. The close correlation between the mean cen- ter of gravity position on anteropos- terior axis (mean y) and velocity variance has been demonstrated ex- perimentally (6) and is expressed by a mathematical relationship: vari- ance (V) =/(mean_y). This function monitors short length-high velocity compensating movements used to maintain the upright position. The VFY parameter evaluates by the dis- tance of the point representative of the subject from the normal curve (9). 3. Fast Fourier transformation on x andy(FFTX, FFTY) (3). 372 DIABETES CARE, VOLUME 19, NUMBER 4, APRIL 1996 Downloaded from http://diabetesjournals.org/care/article-pdf/19/4/372/514678/19-4-372.pdf by guest on 19 June 2022