Postural control characterization according to age and auditory input in cochlear implant users.

Aims/Objectives: Understand the relationship between auditory input and balance motor control. Material and Methods: Twelve prelingual adolescent cochlear implant users (CIU) and 12 adult postlingual CIU were tested by posturography on a force platform with eyes open in two conditions, with the cochlear implant (CI) on and off. Energy consumption (EC) of the body center of pressure sway signal was measured, calculating total EC and divided into three bands of frequencies; low (B1) 0-0.1 Hz, medium (B2) 0.1-1 Hz, and high (B3)1-2 Hz. Wilcoxon and Mann-Whitney tests were used for statistical analysis and the significance level was P ≤ 0.05. Results: Prelingual CIU decrease the EC in low and high frequencies throughout the adolescence (P < 0.05) assessed with the CI turned on, while it did not show any modification with the CI off. Postlingual CIU showed a deterioration of PR related to aging when evaluated with the CIU turned off, P < 0.05 in band 1. However, with the CI turned on they had no significant increase in this age range. Conclusions and Significance: The acoustic input improved EC of postural responses in higher and lower frequencies in adolescence and with aging which suggests a relationship with gross and fine movements involved in postural control.

Peripheral vascular disease - a new vascular disease associated with normal tension glaucoma: a case report.

INTRODUCTION: Normal-tension glaucoma is known as a multifactorial optic neuropathy. A number of lines of evidence suggested that vascular factors played a significant role in the development of normal-tension glaucoma. The mechanisms underlying the abnormal ocular blood flow in normal-tension glaucoma are still not clear. Peripheral vascular disease seems to be associated with glaucoma populations independent of other cardiovascular risk factors. We found this presentation, for the first time, to our knowledge, as another probable vascular abnormality related to our patient with normal-tension glaucoma, although it is necessary to confirm its pathological effect in future studies. CASE PRESENTATION: Our patient was a 48-year-old Spanish man without any personal and family history of interest except for circulatory problems of the lower limbs with repetitive ulcers at the frontal and lateral aspects of his legs. His chief complaint was vision loss when he came to consult us. In exploration, his best corrected visual acuity was 20/20 in both eyes; initial intraocular pressure in the right eye was 14-16 mmHg and in the left eye was 16-18 mmHg, with a mild sclerosis of the lens in slit-lamp examination. No inflammation or pigmented lesion was detected in the anterior chamber. Open angle confirmed by Goldman four quadrants gonioscopy. Funduscopic examination revealed a vertical cup disc ratio of 0.6 in the right eye and 0.8 in the left eye. The patient's neuroretinal rim was normal in the right eye, and superior thinning in the left eye was determined. Examination of the patient's visual field showed inferior mild probable nasal scotoma in the right eye and an inferior deep arcuate scotoma defect in the left eye. His optical coherence tomography examination revealed thinning of the peripapillary nerve fiber layer thickness in the left eye and superior loss of macular retinal ganglion cells in the left eye. Normal intraocular pressure values were measured on the intraocular pressure curve without treatment (maximum value, 18-20 mmHg), discarding higher intraocular pressures measured out of office. Ultrasonic pachymetry measured 515/520 µm, and normal intraocular pressure measured with a PASCAL tonometer ruled out probable corneal biomechanical underestimations. The patient's polysomnography study was normal and excluded sleep apnea syndrome. The patient's serial mean blood pressure was normal, especially in the lower limbs (mean value, 125/70 mmHg), ruling out the possibility of systemic hypotension. Thyroidal and coagulation abnormalities, autoimmune disease, and inflammatory disease were excluded. Normal immunologic study and normal vascular biopsy were observed, as well as normal brain magnetic resonance imaging and a normal carotid vascular study. The primary diagnosis was moderate medium peripheral arterial disease in the lower limbs, which was confirmed by echography after ruling out other probable vascular abnormalities related to normal-tension glaucoma. CONCLUSION: After ruling out other systemic diseases and vascular abnormalities related to normal-tension glaucoma, we found peripheral arterial disease as a probable vascular abnormality related to normal-tension glaucoma in our patient. To our knowledge, this is the first time such a case has been reported. Thus, further research is needed to determine the relevance of these results to the general population.

Sensorimotor interaction in deaf children. Relationship between gait performance and hearing input during childhood assessed in pre-lingual cochlear implant users.

CONCLUSIONS: The results suggest that auditory input is not neutral in motor skills and the complex interaction between them is generated in the earlier stages of childhood development. Objective The assessment of gait performance in pre-lingual deaf children with cochlear implant (CI). METHODS: Gait velocity (GV), using a 10-meter test, was measured by means of three inertial sensors in 10 pre-lingual cochlear implant users (CIU) (10-16 years old) in three sensory conditions: (1) cochlear implant turned on with environmental noise (EN), (2) cochlear implant turned on with EN and with cognitive dual task (DT), and (3) CI turned off (CI-OFF). GV with EN and DT was assessed in a normal hearing control group (CG) (n = 14). Mann-Whitney and Wilcoxon Signed ranked test were used for significance validation. RESULTS: (1) GV in CG was lower in DT than with EN (p = .019). (2) GV was faster in CG with EN compared with the three conditions in CIU (EN, p = .006; DT, p = .0001; CI-OFF, p = .03). (3) CIU had slower GV walking with EN (p = .037) and with DT (p = .022). (4) Dividing the CIU sample by age, the acoustic information generates a slower gait for those implanted after 3 years old.

Chronic balance disorders after acoustic neuroma surgery: assessment of gravitational vertical perception.

CONCLUSION: The head tilt response (HTR) test performed in a group of patients with chronic dizziness after acoustic neuroma surgery showed alterations in the gravitational vertical perception (GV). OBJECTIVE: The assessment of the accuracy in the GV through the HTR test in patients with long-term balance disorders after acoustic neuroma surgery. METHODS: The HTR was performed in two groups of patients that had undergone acoustic neuroma surgery: six uncompensated patients (UPs) who maintained vestibular symptoms 1 year after surgery and two compensated patients (CPs) without vestibular symptoms. Twelve healthy control adults were also tested (control group, CG). Three parameters were measured in the HTR test: steady-state error (SSE), rise time (TRS), and mean energy of the error signal per step (MEE). RESULTS: The UP group showed higher values for the TRS and MEE parameters compared with the CG (p < 0.05) when performing the HTR test to the side of the lesion and to the contralateral side, while the SSE only showed significant higher values when the patient estimated the GV towards the side of the lesion. The two patients in the CP group did not have differences in the three parameters assessed when compared with the CG.

Postural response characterization in elderly patients with bilateral vestibular hypofunction.

CONCLUSIONS: The measurement of the energy consumption (EC) of the body's center of pressure (COP) to maintain the upright stance position was higher in elderly patients with bilateral vestibular hypofunction (BVH) compared with a control group and may be a valid parameter in the assessment of balance disorders. OBJECTIVE: The aim of the study was to evaluate the energy consumption of the COP in elderly patients with BVH. METHODS: The COP was recorded on a force platform (FP) for eight elderly patients with BVH related to aging and eight normal control group subjects. The EC of the COP was calculated using the discrete wavelet transform. The two groups were tested in standing position on the FP in three sensory conditions:1, eyes open; 2, eyes closed; and 3, standing on a foam pad placed on the force platform. Wilcoxon's rank test and multi-factor analysis of variance were used, with the level of significance set at 0.05. RESULTS: BVH patients showed higher values of EC of the COP signal measured in arbitrary units compared with the control group (conditions 1 and 2). None of the BVH patients could perform the test in condition 3. BVH patients had increased EC in the frequency band between 0.1 and 0.78 Hz when the visual information was canceled (condition 2).

Comparación de complicaciones según la técnica utilizada en los implantes cocleares / Comparison of complications by technique used in cochlear implants

Introducción: Las complicaciones son un indicador muy sensible de la utilidad de una técnica quirúrgica. En cirugía de implante coclear se pueden utilizar 3 abordajes: el abordaje clásico utiliza el receso facial (RF) para el paso del electrodo; el abordaje suprameatal (SMA) no requiere mastoidectomía y utiliza la creación de un túnel que pasa por encima del nervio facial para entrar a la caja del tímpano desde atrás, y el abordaje endomeatal (EMA) que se basa en la realización de un canal en la pared posterior del conducto auditivo externo. Material y métodos: Estudio multicéntrico de revisión de 208 pacientes, comparando las diferentes técnicas de abordaje descritas. Se clasificaron las complicaciones en mayores y menores. Resultados: Entre los 208 pacientes implantados el 10,5% (22 de 208) presentó complicaciones, de estas el 2,88% (6 de 208) fueron complicaciones mayores que llevaron a la reimplantación y el 7,69% (16 de 208) fueron complicaciones menores. Comparando los resultados obtenidos por los diferentes grupos, podemos decir que la técnica del RF es la que menos porcentaje de complicaciones mayores tuvo, 1,1% seguida de la técnica EMA con un 2,38% y la SMA con un 3,75%. En cuanto a las complicaciones menores, el grupo operado por SMA tuvo el menor porcentaje presentando el 6,25%, seguido del grupo operado por EMA con el 7,14% y el grupo operado por el RF presentó el 10%. Conclusiones: Las 3 técnicas quirúrgicas descritas muestran un porcentaje de complicaciones muy similar. Por lo tanto, podemos concluir, que las 3 técnicas son seguras y alternativas unas con otras (AU)

Introduction: Complications are a very sensitive indicator of the usefulness of a surgical technique. In cochlear implant surgery, there are 3 principal approaches: the classic approach uses the facial recess (FR), the suprameatal approach (SMA) does not require mastoidectomy and uses the creation of a tunnel over the facial nerve to enter the middle ear, and the endomeatal approach (EMA) is based on the completion of a groove in the posterior wall of external auditory canal. Material and methods: A multicentre review of 208 patients with cochlear implants, comparing the different techniques. The complications were classified into major and minor. Results: Among the 208 implanted patients, 10.5% (22 of 208) had complications. Of these, 2.88% (6 of 208) were major complications and 7.69% (16 of 208) were minor complications. Comparing the results obtained by the different approaches, the FR technique had the lowest rate of major complications (1.1%), followed by the EMA technique with 2.38% and SMA with3.75%. As for minor complications, operations in the SMA group had the lowest rate (6.25%), followed by the EMA group (7.14%) and the group operated on using the FR technique presented the highest (10%).Conclusions: The 3 techniques described show very similar rates of complications. Consequently, we can conclude that they are safe and are alternatives (AU)

Comparison of complications by technique used in cochlear implants.

INTRODUCTION: Complications are a very sensitive indicator of the usefulness of a surgical technique. In cochlear implant surgery, there are 3 principal approaches: the classic approach uses the facial recess (FR), the suprameatal approach (SMA) does not require mastoidectomy and uses the creation of a tunnel over the facial nerve to enter the middle ear, and the endomeatal approach (EMA) is based on the completion of a groove in the posterior wall of external auditory canal. MATERIAL AND METHODS: A multicentre review of 208 patients with cochlear implants, comparing the different techniques. The complications were classified into major and minor. RESULTS: Among the 208 implanted patients, 10.5% (22 of 208) had complications. Of these, 2.88% (6 of 208) were major complications and 7.69% (16 of 208) were minor complications. Comparing the results obtained by the different approaches, the FR technique had the lowest rate of major complications (1.1%), followed by the EMA technique with 2.38% and SMA with 3.75%. As for minor complications, operations in the SMA group had the lowest rate (6.25%), followed by the EMA group (7.14%) and the group operated on using the FR technique presented the highest (10%). CONCLUSIONS: The 3 techniques described show very similar rates of complications. Consequently, we can conclude that they are safe and are alternatives.

Visual gravitational vertical perception in peripheral vestibular hypofunction.

CONCLUSIONS: Rise time in the estimation of the gravitational vertical in the head tilt response (HTR) test is increased in patients with peripheral vestibular lesions and residual chronic dizziness. OBJECTIVE: Assessment of the perception of the gravitational vertical in patients with peripheral vestibular lesions through the HTR. METHODS: HTR was studied in 12 patients with peripheral vestibular lesion, 8 clinically with chronic dizziness and 4 without it; 23 normal subjects were studied as control group. Two parameters of the HTR were assessed, rise time and steady-state error to characterize a dynamical system step response. The Kolmogorov-Smirnov test (alpha = 5%) was used to verify normal distribution (steady-state error, p = 0.53; rise time, p = 0.88). The three sigma ellipse was calculated for the control group. ROC curves were used to measure the sensitivity and specificity of these parameters. RESULTS: Rise time showed increased values in peripheral vestibular lesion patients with chronic dizziness. Two-dimensional analysis (rise time vs steady-state error) allows a better discrimination between patients with peripheral vestibular hypofunction with chronic dizziness and the rest of the studied population.

Balance in Parkinson's disease patients changing the visual input.

The description of the postural responses in Parkinson's disease patients when visual information changes from a stable to a moving visual field analyzing the impact on balance in these patients. METHODS (CLINICAL): Limits of Stability, Body center of pressure and balance functional reserve were measured by means of the force platform in 24 Parkinson's patients in stages 1 and 2 of the Boher classification and 19 volunteers as a control group. Both groups were stimulated with 1-Static visual field and 2-horizontal optokinetic stimulation using a virtual reality system. Postural responses were analyzed using the inverted pendulum as mathematical model. RESULTS: While the control group didn't show significant differences on the postural control between the two sensory conditions (COP p=0.0017, BFR p=0.0025), Parkinson's patients presented significant differences in the area of the center of pressure and the balance functional reserve values between static visual field and optokinetic stimulation. (COP p=0.0017, BFR p=0.0025). CONCLUSIONS: The results support the hypothesis about the influence of the changes in the visual information in triggering balance control disorders in Parkinson's patients. It is discussed the interest of these fact in the assessment and the rehabilitation programs of this disease.

Balance in Parkinson's disease patients changing the visual input / Equilíbrio na doença de Parkinson alterando as informações visuais

The description of the postural responses in Parkinson's disease patients when visual information changes from a stable to a moving visual field analyzing the impact on balance in these patients. METHODS (CLINICAL): Limits of Stability, Body center of pressure and balance functional reserve were measured by means of the force platform in 24 Parkinson´s patients in stages 1 and 2 of the Boher classification and 19 volunteers as a control group. Both groups were stimulated with 1-Static visual field and 2-horizontal optokinetic stimulation using a virtual reality system. Postural responses were analyzed using the inverted pendulum as mathematical model. RESULTS: While the control group didn't show significant differences on the postural control between the two sensory conditions (COP p=0.0017, BFR p=0.0025), Parkinson's patients presented significant differences in the area of the center of pressure and the balance functional reserve values between static visual field and optokinetic stimulation. (COP p=0.0017, BFR p=0.0025). CONCLUSIONS: The results support the hypothesis about the influence of the changes in the visual information in triggering balance control disorders in Parkinson's patients. It is discussed the interest of these fact in the assessment and the rehabilitation programs of this disease.

Descrição das respostas posturais em pacientes com doença de Parkinson quando a informação visual muda de um campo visual estável para um móvel, analisando o impacto do equilíbrio nesses pacientes. MÉTODOS (CLÍNICO): Limites de estabilidade, centro de pressão corporal e reserva funcional do equilíbrio foram medidos em uma plataforma de força em 24 pacientes com doença de Parkinson nos estágios 1 e 2 da classificação de Boher e em 19 voluntários de um grupo controle. Ambos os grupos foram estimulados a partir de um campo visual estático e dois estímulos optocinéticos horizontais, usando-se um sistema de realidade virtual. As respostas posturais foram analisadas usando-se o pêndulo invertido como modelo matemático. RESULTADOS: Enquanto o grupo controle não demonstrou diferenças significativas no controle postural entre as duas condições sensoriais (COP p=0,0017, BFR p=0,0025), os pacientes com doença de Parkinson apresentaram diferenças significativas na área do centro de pressão e nos valores de reserva do equilíbrio funcional entre o campo visual estático e a estimulação optocinética (COP p=0,0017, BFR p=0,0025). CONCLUSÕES: Os resultados corroboram a hipótese sobre a influência das mudanças na informação visual deflagrando distúrbios no controle do equilíbrio em pacientes com doença de Parkinson. Discutimos esse fato com relação à avaliação e programas de reabilitação associados a essa doença.

Clinical characteristics of positional vertigo after mild head trauma.

CONCLUSION: This study showed that a population with benign paroxysmal positional vertigo related to mild head trauma (BPPVAT) was younger and more frequently presented with bilateral canalithiasis than another population with idiopathic etiology (IBPPV). In both groups, females presented a higher risk of BPPV. OBJECTIVE: To compare the clinical features of a population with BPPVAT and another with IBBPV. METHODS: We carried out statistical analysis of a population of 51 subjects with BPPVAT and another of 325 subjects with IBPPV, comparing age, gender, recurrence of symptoms, associated chronic dizziness (CD), and clinical presentation. Kolmogorov Smirnov test, Student's t test, Mann-Whitney test, 95% binomial confidence interval for proportions, chi-squared, and Fisher's test were used as statistical tools. A significance level of p < 0.05 was considered in all cases. RESULTS: The population affected with BPPVAT was younger and bilateral canalithiasis was also more frequent. No differences were found in gender distribution, semicircular canals involved in the symptoms, recurrence after repositioning maneuvers, or associated CD.

Dynamic modeling and experimental results for a head tilt response.

The estimation of the vertical in humans is important in everyday life although the mechanisms involved are not completely understood yet. This paper presents two sets of experiments with normal subjects, using the same virtual reality setup, aiming to help in this understanding. First, a steady state experiment is presented, which is used to determine the gravitational vertical precision while the second, a dynamical transient response experiment, is used to find dynamic models of each subject response. Results show that the dynamic models are able to reproduce the results of the steady state experiment while having the benefits that a dynamic model brings to evaluate subjects performance.

Head tilt response: A complementary test to the Subjective Visual Vertical.

This paper studies the phenomenon of the perceived vertical by means of a novel dynamic experiment. This task is inspired in the Subjective Visual Vertical test and can be regarded as complementary in terms of how the information involved varies (visual, otolithic and neck proprioception). The experiment consists in presenting a white stripe in a pair of virtual reality goggles and adjusting the roll angle of the head until the stripe is aligned with the gravitational vertical. The roll angle of the head is measured and recorded along each trial where the white stripe changes position four times, after a specific amount of time. The task was run on a group of 28 normal subjects and a small sample of 5 patients with vestibular hypofunction. Six parameters derived from Control Theory were extracted from the data to characterize the subject transient response. All parameters for normal subjects were found to be normally distributed. Experimental results show that discrimination is possible between normal subjects and patients using just one or two of the parameters studied.

Postural control and sensory perception in patients with Parkinson's disease.

CONCLUSIONS: This study suggests that patients with Parkinson's disease (PD), even in the early stages, have decreased body limits of stability (LOS) and changes in the visual input impair their postural control. OBJECTIVE: To assess the LOS and the postural responses after changes in visual input in a group of PD patients in stage 1 of the Hoehn and Yahr classification. SUBJECTS AND METHODS: Twenty PD patients in stage 1 and a group of 24 normal subjects as control were assessed in two tests: (1) the LOS and (2) measurement of the body center of pressure area (COP) 10 s before and after sudden change in visual flow velocity. We also investigated labeling of the COP trajectory in these two periods. The stimulation paradigm was a horizontal optokinetic stimulation (60 degrees /s and suddenly stopped) using a virtual reality system. RESULTS: LOS showed significant decrease in PD patients as compared with the control group (p<0.001, Kruskal-Wallis and Wilcoxon ranked test). The COP values increased significantly (p<0.001, Wilcoxon signed rank test) after sudden changes in the visual flow velocity in relation to the control group. After the visual stop the PD patient showed a spatial 'roaming' approaching the limits of stability and therefore impairing the postural control.

Postural strategies in normal subjects and in patients with instability due to central nervous system diseases after sudden changes in the visual flow.

CONCLUSION: The results suggest that after a sudden change in the visual input, postural adaptation is impaired in patients with instability and central nervous system disorders (CNSD). OBJECTIVE: The aim of this study was the assessment of postural adaptation, as a transient phenomenon, when sudden changes in visual perception occur in normal subjects and in patients with instability due to different CNSD. SUBJECTS AND METHODS: Horizontal optokinetic stimulation (40 s and suddenly stopped) was performed in 16 patients with CNSD, and also in 22 normal subjects. Measurements were made of the body center of pressure area (COP) and the body sway velocity (SV) during 10 s before and after the stop and labeling the COP trajectory. RESULTS: Values of COP and SV (Wilcoxon signed rank test, p=0.979 and 0.496, respectively) in normal subjects did not show any significant change before and after the stop. In 15 of the 16 assessed patients with instability associated with CNSD an increase of the COP and SV values (Wilcoxon signed test, p=0.001 and 0.004, respectively) was observed in the 10 s after the visual stop. COP labeling showed 'roaming' of the COP spatial evolution approaching the limits of stability.

The effect of general and spinal anesthesia on balance control in elderly patients.

Falls are a major problem in the elderly population, but few communications address the influence of anesthesia on balance control. This study reports how a general balanced anesthesia (GBA) and a spinal anesthesia (SA) affect balance control in the elderly. We divided into three groups, according to electronystagmography findings and type of anesthesia, 21 men older than 65 years (mean age, 72 years) who were scheduled for prostate adenectomy. One group, designated GBN, consisted of normal subjects who underwent surgery under GBA. In another group, designated GBP, were pathological subjects who had clinically compensated central vestibular disorders (CVDs) and underwent surgery under GBA. The third group, designated SP, contained CVD patients who underwent surgery under SA. We assessed balance control via static posturography preoperatively and 48 hours postoperatively. We observed no change in balance control parameters (center of pressure distribution area [COPa] or COP sway velocity [SV]) for those patients in the GBN group or for those in the SP group. We did observe a significant difference for the patients in the GBP group, with higher postoperative values of COPa and SV (Wilcoxon signed rank test). Our results showed that in subjects with clinically compensated underlying CVD prior to a GBA, balance control worsens after the procedure, whereas no change in balance control occurs after an SA. Balance control in subjects with normal vestibuloocular function did not change even after a GBA.

Prevalence and characteristics of immunomediated neuropathies in a group of patients with autoimmune diseases.

OBJECTIVE: To determine the prevalence and the clinical-neurophysiological characteristics of immunomediated peripheral neuropathies (PN) in a group of patients with systemic autoimmune diseases. METHOD: Fifty-nine patients with proved systemic autoimmune diseases were included. Patients underwent clinical examination and nerve conduction studies to diagnose the PN. RESULTS: Immune PNs were detected in 18 patients (30.5%). Out of the total number of PNs (18), 39% were sensory-motor polyneuropathies, 33% mononeuritis multiplex, 11% pure sensory polyneuropathies, 11% cranial neuropathies, and 6% proximal motor neuropathies, such as the Guillain-Barré syndrome. Nine PNs (50%) appeared at the onset of the connective tissue disorders, and the rest of the cases appeared during the course of the disease. Of the total of PNs detected in this study, only 45% had a previous diagnosis. Vasculitis was the disease that presented more associated PNs. Systemic lupus erythematosus showed the widest range of PN clinical varieties. CONCLUSIONS: The first national prevalence rate of PNs in patients with systemic autoimmune diseases was provided: 30.5%. No comparative data were found in the international bibliography. Sensory-motor polyneuropathy was the most frequently observed form of PN, followed by mononeuritis multiplex. The NPs appeared with the same frequency both at the onset and during the course of the diseases under study; these predominated at the onset of vasculitis and primary Sjögren syndrome. The compromise of the peripheral nervous system is underdiagnosed.

Postural adaptation in elderly patients with instability and risk of falling after balance training using a virtual-reality system.

Our aim in this study was to assess postural control adaptation quantitatively in unsteady elderly patients at risk of falls in open spaces and given balance training with a virtual-reality system reproducing environmental stimulation. Using a balance rehabilitation unit based on a virtual-reality system that changes sensory information (visual, vestibular, and somatosensory), we treated 26 elderly, unsteady patients who were prone to falling (age range, 73-82 years) and who were enrolled in a customized vestibular rehabilitation program. We assessed postural responses by posturography before and after 6 weeks in the vestibular rehabilitation program under two conditions: (1) standing, eyes open, static visual field, and (2) standing, eyes open, dynamic visual field through virtual-reality goggles, generating horizontal optokinetic stimulation (70 degrees per second angular velocity). We recorded postural responses with a platform measuring the confidential ellipse of the center-of-pressure distribution area and sway velocity with a scalogram analyzing postural behavior by wavelets. After 6 weeks of treatment, postural response confidential ellipse and sway velocity values were lower, evincing decreased amplitudes and sway frequency contents in the scalogram by wavelet under both stimulation paradigm conditions. These findings suggest postural adaptation under the two perceptual conditions when patients had static and dynamic visual fields. The possibility of treating elderly fallers with balance disorders using a virtual-reality environmental stimulation reproduction system is discussed.