Biomedical subjects

F Sorace

Publications and source records attributed to F Sorace.

3 recordsLinked to original sources

PubMed1998

[Postural stabilization after otolithic repositioning for posterior semicircular canal canalization].

Today the canal/cupulolithiasic pathogenesis of benign paroxysmal positional vertigo (BPPV) appears well defined; what is less clear is the origin of the postural "instability" often associated with rotatory vertigo. This form is less marked but still resists all know treatments. The purpose of the present study was to determine the actual postural arrangement of subjects suffering from canalolithiasis (CL) of the posterior semicircular canal (PSC) both before and after the positioning maneuver. In this case a personal method of spectral frequency analysis was used in an attempt to clarify the origin of the residual "instability" following otolithic repositioning. Static posturographic testing was performed on 20 patients with CL of the PSC and another 20 normal subjects of comparable age. In the present study the repositioning maneuver leads to a reduction in latero-lateral oscillation without any anterior-posterior variation. Such stabilization covers all the frequencies if a visual input is also present while it is limited to the lower frequencies when the visual content is lacking. In fact, in the latter case the subject maintains his posture using only vestibular and proprioceptive input. On the other hand, the anterior-posterior oscillations increase in all frequency ranges and this increase remains essentially unchanged after the repositioning maneuver. The authors feel that the anterior-posterior destabilization seen in CL of the PSC may stem from a proprioceptive-macular alteration linked to otolitic detachment rather than abnormal ampullar stimulation. The persistence and residual postural alterations found could, therefore, explain the persistent sense of instability that CL patients often complain of, even after the maneuvers which have encountered such success in controlling BPPV.

Adult↗

PubMed1998

[Alterations in postural control: the use of spectral analysis in stability measurement].

UNLABELLED: Static posturography studies the frequency at which the center of gravity in the human body oscillates. There is no universal agreement as to the importance of this index or whether it is specific in identifying alterations in the postural control systems (vestibular, proprioceptive and visual). Nevertheless, some hypotheses appear generally accepted: a) visual information dominates; b) proprioception affects anterior-posterior oscillation; c) relatively low frequency body oscillation is affected by vestibular input while higher frequency oscillations are controlled by proprioceptive information. In order to check these hypotheses, four groups of patients underwent spectral analysis of bodily oscillations recorded with static posturography. The four groups of patients were similar in terms of age and broken down as follows: Group A-peripheral diabetic neuropathy (10 cases); Group B-diabetic neuropathy-free patients (10 cases); Group C-pure peripheral vestibulopathy (10 cases); Group D-normal subjects (20 cases). Analysis was performed dividing the frequency spectrum (FFT) into three groups: gr. I) 0.01-0.7 Hz; gr. II) 0.7-1 Hz; gr. III) > 1 Hz. Analysis of the spectra for Group A showed a significant increase in high frequency bodily oscillation (gr. III) with the eyes open in the anterior-posterior direction (M = 8.6 +/- 5.5; p < 0.05) and in the lateral direction (M = 4.0 +/- 2.0; p < 0.05); an increase was also found in both directions with the eyes closed (M = OCX II: 7.4 +/- 1.5; p < 0.05) (M = OCX III: 5.6 +/- 1.6; p < 0.01) (M = OCY II: 16.8 +/- 5.0; p < 0.05) (M = OCY II: 9.2 +/- 4.4; p < 0.05). In Group B the increase was limited to high frequency anterior-posterior oscillations (gr. III) at open eyes (M = 3.6 +/- 1.6; p < 0.05) and at closed eyes (M = 4.4 +/- 1.5; p < 0.05). In Group C there was an increase in high frequency lateral oscillations (gr. III) at open eyes (M = 4.2 +/- 0.5; p < 0.01) and panfrequency oscillations at closed eyes (M = OCX I: 47.7 +/- 5.6; p < 0.01) (M = OCX II: 23.2 +/- 4.9; p < 0.01) (M = OCX III: 7.2 +/- 2.3; p < 0.05). CONCLUSIONS: The diabetic proprioceptive deficit appears to lead to multiplanar destabilization at the medium-to-high frequency range. The labyrinthine deficit, on the other hand, appears to cause lateral destabilization at all frequencies. The method of analysis used appears to provide useful parameters with which to evaluate static posture since they can specifically identify alterations in orthostatic bodily control of various origins.

Adult↗

PubMed1997

[Changes in posture in whiplash evaluated by static posturography].

Analyzing vestibular-spinal reflex by recording changes in the pressure center over time, static posturography provides precise, repeatable information regarding a person's posture and subsequent postural strategy. Moreover, using the detected postural pattern, this can presage likely genesis of problems in equilibrium. The purpose of the present work was to evaluate posturographic findings in subjects with chronic or persistent whiplash (WL)-induced disequilibrium in order to determine any clear postural pattern able to indicate the likely genesis of the disorder. Fifty young subjects were selected for the study: 28 (6 females) affected with equilibrium problems resulting from WL-type cervical strain and 22 (5 females) normal, age compatible controls (C) (mean age of the groups: WL = 37 +/- 14.3; C = 32.4 +/- 6.7; p = n.s.). The results obtained were statistically processed with a personal computer and specific software (Windows-SPSS). In the analysis of the means (T-test and ANOVA analysis of variance) p < 0.05 was considered significant. In the WL group there was an increase in the antero-posterior axis oscillation frequency as compared to the control group. This is indicated by the FFTY parameter in tests performed both with eyes open and closed. Likewise, in both tests, there was a decrease in the LFS value, a parameter correlating length with surface. The surface was increased in the WL group as compared to group C although this increase was significant only when the test was performed with eyes closed. In addition, the average velocity and standard deviation of velocity increased in the WL group but this was only statistically significant when the eyes were open. The results obtained in the present study show that whiplash victims show an increase in antero-posterior oscillation frequency at the pressure center, as found in the open and closed-eye tests. This suggests that in WL subjects there is an evident disturbance of the fine postural system, leading to an increase in the surface parameters, tracing length and a decrease in LFS function. The onset of this partial postural decompensation can be seen in: a) decrease in fine static postural control which is reflected in an increase in body surface oscillation; b) an increase in energy consumption to maintain orthostatism as revealed in the decreased LFS. In conclusion, it appears reasonable to assume that cervical proprioceptive alterations play a preeminent role in the genesis of whiplash-induced chronic postural instability. This would result in an attempt to vary the physiology from an ankle to a hip strategy; incomplete manifestation of this new posture would cause the feeling of instability mentioned by the patients and documented by posturography.

Adult↗