Clinical Research On The Vestibulospinal Reflex Function And Vestibular Rehabilitation Therapy

PartⅠThe timed balance test and static posturography in the patients with unilateral vestibular hypofunctionObjective To investigate the balance function of the patients with unilateral vestibular hypofunction (UVH) by timed balance tests and static posturography (SPG).Methods 65 subjects with UVH and 92 healthy adults were taken the timed balance tests under differential stance including①standard Romberg test,②feet apart stance test,③tandem stance (TS) and④unilateral standing (US) tests with eye open (EO) and eye closed (EC). The average timing that subjects kept balance before falling under different standing conditions was recorded by stopwatch. The body sway velocity (SV) during the test①and②were also recorded by the SPG.Results The time of keeping balance under TS and US with EO and EC in the UVH group is decreased (P<0.001) compared with the control group. The SV under standard Romberg test and foot apart stance with EO was not different between the UVH group and control group (P-value was 0.118 and 0.110 for the two test respectively), and the difference was significant while with EC condition (P<0.001). For two groups, the SV under foot apart was decreased than under standard Romberg test with EO and EC (P<0.05 or P<0.001). The timed results under both TS and US and SV under both the standard Romberg test and the feet apart stance did not correlated for the two groups.Conclusions According to clinical assessment of balance function in UVH, the tandem stance test and unilateral stance test could provide the additional information to the SPG measurement. The effect of foot position on the results of SPG should been considered in clinic. PartⅡPostural characteristics of healthy subjects under different thickness of foamObjective To investigate the effects of different thickness of foam on the postural control of standing in healthy subjects.Methods 30 healthy adult subjects(11 males,19 females)were taken into examination of computerized posturography measurement under different surface conditions including the firm surface and 1 to 5 layer foams of medium density with 4.7cm high respectively in stance of feet together with eye open (EO) and eye closed (EC) for 30 seconds. The following time-dominated parameters regarding to the center of pressure (COP) movement were used to evaluate the postural stability: whole path length (WPL), unit path length (UPL) which means the sway velocity of the COP movement, unit area path length (UAPL), circumference area (CA), effective value area (EVA) and rectangle areas (RA).Results All parameters have the increased tendency when the layer of foam is added with both eye open and closed conditions except the UAPL, which has a decreased tendency. The parameters under differential layer foam were significance(P<0.05)except the following conditions:①WPL and UPL under layer 4 to 5 with EO and EC;②UAPL under layer 0 to 1, layer 1 to 3, layer 2 to 3, layer 3 to 4, layer 4 to 5 with EO, layer 3 to 4, layer 3 to 5 and layer 4 to 5 with EC,③CA under layer 2 to 3, layer 3 to 4, layer 4 to 5 with EO, layer 3 to 4, layer 3 to 5, layer 4 to 5 with EC;④RA and EVA under layer 2 to 3, layer 4 to 5 with EO, layer 3 to 4, layer 3 to 5, layer 4 to 5 with EC.Conclusions The whole path and velocity of movement of COP is the stable and sensitivity parameters to evaluate the postural stability under foam by the posturography. It is important that the thickness of foam should be considered for interrupting the proprioception during the sensory interaction test in clinical. PartⅢThe modified clinical test of sensory interaction and balance under difference surface conditions in patients with vertigoObjective To investigate the influence of different surface condition on the modified clinical test of sensory interaction and balance (mCTSIB) in the patients with vertigo.Method 33 patients with vertigo were taken into examination of computerized posturography measurement under different surface conditions such as the hard surface and 1 to 5 layer foams of medium density with 4.7cm high respectively in stance of feet together with eye open and eye closed for 30 seconds. The interval between two trials was 2 to 3 minutes for enough relaxation. The time-dominated parameter of unit path length (UPL), which means the average sway velocity(SV) of the center of pressure (COP) movement with different surface conditions were used for the analysis. The timing that subjects keeping balance without falling was recorded.Results①The SV has the increased tendency when the layer of foam was added with both eye open and closed conditions. The difference of the SV between the hard surface and 1 to 4 layer foam respectively are significanc(eP<0.0001)with eye open and closed. The SV has not different while standing in the 4th and 5th layer foam with both eye open and closed because the P value were 0.0503 and 0.3422 for this two conditions respectively. The SV with eye closed and the thickness of foam was negative correlation(r=0.67765,P<0.0001).②The timing that subjects keeping balance without falling has the decreased tendency when the layer of foam was added with eye closed. The timing and the thickness of foam was negative correlation(r=-0.35565,P<0.0001). According to the absolute value of the correlate coefficients, the SV was sensitive to the change of thickness of foam than the timing with eye closed. The SV and timing in eye closed condition was negative correlation(r=-0.40137,P<0.0001).③According to the case of fall under different thick foam with eye close, there are significant differences(P<0.001)between the 1 layer and the 2 to 5 layer, while the cases of fall under 2 to 5 layer are not statistical difference(P>0.5).Conclusions The different thick foam can affect the results of mCTSIB including the SV with both eye conditions and timing with eye close. Through quantitative measurement the sensory interaction in patients with vertigo.PartⅣThe application of mCTSIB in the clinicalObjective To investigate the application of foam posturography (FPG) in the normal subjects and patients with vertigo. The mechanisms of sensory interaction in the postural control in the normal and patients with vertigo were also discussed.Methods 106 normal subjects and patients with vertigo individually were taken the computerized posturography under the firm surface and foam surface with eye open and eye closed for 30 seconds respectively. The standing foam surface was to interrupt the somatosensory and closing eyes was to interrupt the visual input in the postural stability. The sway velocity (SV) of body under different sensory conflict condition was recorded as parameter of postural stability and the effect of organization between the vestibular, visions and somatosensory was analyzed quantitatively. The patients with vertigo were also taken the videonystagmography (VNG).Results (1) For the normal subjects,①the SV decreased when the visual cue or/and somatosensory cue be interrupted (P<0.0001).②The decreased degrees of SV induced by the change of visual cue were (12.12±6.1)and (30.58±9.69)% when the somatosensory cue be interrupted or not. The decreased degrees of SV induced by the change of somatosensory cue were (18.31±6.56)and (36.25±8.90)% when the visual cue be interrupted or not. The decreased degrees of SV induced by the change of both somatosensory and visual cue were (46.21±8.67)%.③The most important sensory input for keeping balance is vestibular cue and following by the somatosensory and visual cues and the relationship among these three sensory is non-line. (2) For the patients with vertigo,①The abnormality rate of VNG in the vestibular periphery and central disorder was 67.74% and 22.73%, which has a significant difference between this two kind disorders (χ~2=20.867,P<0.001).②When the abnormality of FPG was assessed by the falling and SV, the abnormality rate of FPG in the vestibular periphery and central disorder was 58.06% and 40.91%, which has not a significant difference between this two kind disorders(χ~2=3.031,P=0.082).③When the abnormality of FPG was assessed only by the falling, the abnormality rate of FPG in the vestibular periphery and central disorder was 45.16% and 27.27%, which has not a significant difference between this two kind disorders (χ~2=3.505,P=0.061).④There were four types abnormality of sensory organization including the only T4 abnormality, T2+T4 abnormality, T3+T4 abnormality and T2+T3+T4 abnormality. The difference of constituent ratio of this four types abnormality between the peripheral and centeral vertigo disorder was not significant (χ~2=2.838, P=0.417).Conclusions Through recording the postural stability quantitatively under different conditions of sensory conflict induced by standing foam surface or closing eyes, it is possible to evaluate the sensory organization of the three kinds of sensory input including the visual, somatosensory, and vestibular input in postural control. It exist the various balance strategy for keeping postural stability under sensory conflict in normal subjects. When one or two sensory input was interrupted in the static balance, the center nervous system has a complicated mechanism of sensory organization to keep balance even in the normal subject. The abnormality of the FPG and the categorization of abnormality of sensory interaction could not differentiate the vestibular periphery and central disorder. But this method can assess the posture control strategy of the patients with vertigo, and the results about the sensory interaction can guide the vestibular rehabilitation therapy in the patients with vertigo.PartⅤThe effect of the head extension on the postural stability in the normal subjectsObjective To investigate the effect of head extension on the postural stability in the healthy young subjects.Methods 34 healthy young subjects were taken in the posturography including four conditions, such as (1) firm surface and head erected; (2) firm surface and head extension; (3) foam surface and head erected; (4) foam surface and head extension. Each condition was tested under eye open and closed. The body sway velocity (SV) was analyzed.Results (1) SV under foam surface was greater than those under firm surface with EO (t=15.484,P<0.001) and EC (t=19.302,P<0.001) when the head was in the erected position. (2) The difference of SV between the head erect and head extension was not significance without the surface is firm or foam when the eye was open. While under eye close condition, The SV with head extension was greater than that with head erect under two surface conditions. (3) The body sway increase ratio under foam surface was greater than that under firm surface when the head was put in the extension with eye close (t=5.757, P<0.001).Conclusion: The postural stability decreased when the head is put in extended orientation in static standing with eye closed in normal individuals. Head extension may increases the reliance on the proprioceptive input.PartⅥEffect of somatosensory input in postural stability with head extensionObjective To investigate the role of somatosensory in the postural stability during the head extension in healthy young subjects.Methods 42 healthy young subjects were taken the posturography under six conditions that the standing surfaces were firm and foam of two kind height while the head put in upright and extension. The postural stability was recorded as sway velocity (SV) and sway area (SA) under eye open (EO) and eye closed (EC) respectively. The body-sway increase ratio when the head put extended orientation between differential surfaces was also analyzed.Results (1) For the SA and SV between the head-erected and head-extension under differential surface and visual condition, the body sway was not significant difference with EO under all surface, while the body sway under head-extension were greater than that under head-erected with EC under three kinds of surface. (2) For the BIR under differential standing surface with EC, the difference between the firm surface and 2 layer foams were not significance for the SA and SV, while the BIR under 4 layer foams was great than those under firm and 2 layer foams standing surface for the SA and SV. Conclusion The head extension increases the reliance on the proprioceptive input. While the head put in the extension orientation, the greater interruption for the proprioceptive input, the worse postural stability.PartⅦPostural instability induced by the head extension in the patients with unilateral peripheral vestibular disorderObjective To investigate the postural instability induced by the differential head orientation while interrupting the proprioceptive input with standing foam in the unilateral peripheral vestibular disorder (uPVD).Methods 28 patients with uPVD were taken in the posturography including four conditions, such as (1) firm surface and head erected; (2) firm surface and head extension; (3) foam surface and head erected; (4) foam surface and head extension. Each condition was tested under eye open and closed. The body sway velocity (SV) was analyzed.Results (1) There were not falling in the test of standing on the firm surface. The SV had not significant different between the head erect and head extension with eyes open (t=0.043, P=0.966), while there were significant difference with eyes closed (t=4.735, P<0.001). (2) There were not falling in the test of standing on the firm surface with eyes open, and the SV did not showed difference between two head position (t=1.113, P=0.275). (3) In the foam standing with eyes closed, there were 4 cases of falling when the head was erect. While in the head extension, there were 6 cases of falling in three trials and 2 cases in the one trial. The SV showed significant difference between two head position (t=3.015, P=0.007). The difference of falling cases between head erect and head extension was not significant (χ~2=1.693, P=0.193). (4) For the body sway increase ratio induced by the head extension with eyes closed, there was not significant difference between the firm and foam surface (t=2.036, P=0.055).Conclusions The postural stability decreased with the eyes closed in the patients with uPVD, which was consisted with that of the normal subjects. It indicated that the posturography with the head extension may not an ideal method to differentiate the compensated patients with uPVD from the normal subjects. PartⅧEffect of canal repositioning procedure on the postural stability in patients with benign paroxysmal positional vertigoObjective To investigate the effect of canal repositioning procedure (CRP) on the postural stability in patients with benign paroxysmal positional vertigo of the posterior canal (BPPV-PC) of the posterior semicircular canal.Methods 25 patients with BPPV-PC were taken the posturography before and after the CRP. The posturography test including four conditions, such as (1) firm surface with eyes open (EO); (2) firm surface with eyes closed (EC); (3) foam surface with EO; (4) foam surface with EO. The body sway velocity (SV) recorded by the posturography was analyzed as parameter of postural stability. The postural stability of the patients with BPPV-PC was compared with the matched control group.Results①The SV of the BPPV-PC patients before the CRP was greater than that of control group (P<0.05 or P<0.001).②For the BPPV-PC patients, the SV showed decrease after the CRP except that test condition 1 (firm surface with EO).③There were not differences of the SV between the BPPV-PC patients after the CRP and the control group in the test with the firm surface (PEO=0.178, PEC=0.055), while there were still differences in the test with foam surface (PEO=0.004, PEC=0.029).Conclusions A deficit of postural stability was presented in the patients with BPPV-PC decreased. Treatment of BPPV-PC by the CRP can result in improved postural stability in the patients with BPPV-PC, but there was still somewhat difference compared with the normal subjects.