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An analysis of the sectorial structure of energy consumption shows that residential and tertiary sector buildings are the third-highest consumers, responsible for 29.5% of a city’s final energy consumption. The Building Quality Control Laboratory of the Basque Government aims to promote quality, innovation, and sustainability in buildings. To accomplish this goal, it has constructed an experimental facility with different energy generation technologies and a very versatile control system for testing different energy systems and operation modes. In this study, we tested a facility for supplying domestic hot water and heating for a multi-family house by means of a condensing boiler and an aerothermal heat pump (together with the corresponding control). This installation could reproduce the thermal demands required to be satisfied by the generation equipment through a programmed operation of the installation based on real demands. Additionally, this installation was analyzed using thermoeconomics (TE) to solve problems unable to be solved using traditional energy analyses based on the First Law of Thermodynamics. These problems include: (1) Determining the costs of the products of the installation based on physical criteria, (2) detecting the places where losses actually occur, evaluating their costs, and proposing cost-effective improvements, and (3) diagnosing issues in the installation. As a result, this paper suggests a solution to the preventive maintenance problems confronting the technical maintenance personnel for thermal installations in buildings by applying TE knowledge and using real data collected from sensors.

In hospitals, operating rooms are energy-intensive spaces, due to the high flow of outside air required to achieve the necessary indoor air quality. Operating rooms demand ventilation continuously, despite periods of low daily surgical activity. However, by controlling ventilation during inactive periods in the operating room, significant energy savings can be achieved, avoiding penalties on IAQ levels. This paper evaluates the energy savings achieved by introducing ventilation flow control and regulation systems in operating rooms of hospitals located in different climatic zones within Spain. In addition, emissions and economic savings have also been evaluated. Two control and regulation strategies of the air flow to be supplied and extracted in the operating rooms, during periods of inactivity, are studied and include regulation by schedule and regulation by occupancy. Data from a 900-bed university hospital center are used as a reference to evaluate the average occupancy of the operating rooms, and the energy consumption, thus validating the model for calculating the demand of a typical operating room. The energy savings for the regulation by occupancy are 37.5%, and the regulation by schedule are 40% of the annual demand, with respect to an operating room working permanently.

The high energy consumption of cooling systems justifies the need for strategies to increase the efficiency of the facilities, in order to reduce the related CO2 emissions. This study aims to improve the performance and reduce the energy consumption of an 8.6 MW air cooled chiller. This installed capacity is biased due to the screw compressors, of 2.98 Energy Efficiency Ratio (EER) at full load (characteristics provided by the manufacturer). The chiller unit has been modified by placing evaporating cooling pads before the condensing coils. The chiller has been monitored for three months, recording over 544,322 measurements (5 min-step data), with and without the evaporative cooling pads, to assess the performance. Data comparison has been done by selecting two days (with and without evaporative panels) with the same health care load and temperatures. Implementing the proposed strategy yields an improvement in the European Seasonal Energy Efficiency Ratio (ESEER) from 3.69 to 4.83, while the Total Equivalent Warming Impact (TEWI) decreases about 1000 tCO2. Energy savings of up to 32.6 MWh result into a payback period lower than 2 years.

The EU Energy Performance of Buildings Directive (Directive 2010/31/EU) poses a major challenge, as it promotes the transformation of existing buildings into nearly zero-energy buildings (NZEB). In this work, we present the case of study of a lecture hall building, owned by the University of Valladolid (Spain), that is currently being refurbished into a NZEB by integration of renewable energy sources (RES), also in line with the requirements from Directive 2009/28/EC. As part of its major renovation, not only Trombe walls and geothermal energy are to be incorporated but also a building-integrated solar photovoltaic (BIPV) system to address the electricity needs and reduce the building’s energy use and GHGs in a cost-effective manner. The environmental profile of this BIPV system has been investigated using life cycle impact assessment (LCIA), assessing the net emissions of CO2 and the damages caused in a comparative context with conventional electricity-generation pathways. In spite of the small power installed in this first stage (designed to cover only an annual energy consumption of about 13,000 kWh, around 6% of the total demand), it can be concluded that significant environmental benefits are gained using this system.

In order to achieve the objectives of the European 20/20/20 strategy, and to obtain a greater energy efficiency, integration of renewable energies and the reduction of carbon emissions, a District Heating (DH) system has been designed by the University of Valladolid (UVa), Spain, one of the most important DH fed by biomass fuel in Spain, supplying heating and domestic hot water (DHW) to 31 buildings in Valladolid, the majority of them, educational buildings on the University Campus. The aims of this paper were to study the change from an energy system fueled by natural gas to District Heating by biomass in a building on the campus of the University of Valladolid—the School of Engineering (EII)—studying its consumption from its connection to the District Heating system. An energy management methodology such as ISO 50001 is carried out, applied to efficiency systems in buildings, thus establishing new criteria of sustainability and economic value. In this paper, energy management will also be analyzed in accordance with the proposed tools of an Energy Management System (EMS) applied to the EII building, through the measurement of energy parameters, calculation of thermal consumption, thermal energy savings as a result of the change from system to District Heating by biomass, economic savings, reduction of environmental impact and indicators of thermal efficiency I100 and CUSUM indicator. Finally, the primary renewable and non-renewable energy efficiency indicators for the new District Heating system will be determined. The concept of the near Zero Energy Buildings is defined in the European Union (EU) in order to analyze an approach to an nZEB which results from replacing the natural gas heating system by a biomass District Heating system.

The building sector is responsible for a substantial part of the energy consumption and corresponding CO2 emissions. The European Union has consequently developed various directives, among which the updated Energy Performance of Buildings Directive 2018/844/EU stands out, aiming at minimizing the energy demand in buildings, improving the energy efficiency of their facilities and integrating renewable energies. The objective of the present study was to develop an analysis on the energy performance, related CO2 emissions and operating costs of the renewable energy technologies implemented within a multipurpose near Zero Energy Building (nZEB). The target building is an existing nZEB called LUCIA, located in Valladolid (Spain). Monitoring data provides the required information on the actual needs for electricity, cooling and heating. It is equipped with solar energy photovoltaic systems, a biomass boiler and a geothermal Earth to Air Heat Exchanger (EAHX) intended for meeting the ventilation thermal loads. All systems studied show favourable performances, but depend significantly on the particular characteristics of the building, the control algorithm and the climate of the location. Hence, design of these strategies for new nZEBs must consider all these factors. The combined use of the PhotoVoltaic PV System, the biomass and the EAHX reduces the CO2 emissions up to 123 to 170 tons/year in comparison with other fuels, entailing economic savings from the system operation of up to 43,000⁻50,000 €/year.

This article analyses the reduction of energy consumption following the installation of district heating (DH) in the Miguel Delibes campus at the University of Valladolid (Spain), in terms of historical consumption and climate variables data. In order to achieve this goal, consumption models are carried out for each building, enabling the comparison of actual data with those foreseen in the model. This paper shows the statistical method used to accept these models, selecting the most influential climate variables data obtained by the models from the consumption baselines in the buildings at the Miguel Delibes campus through to the linear regression equations with a confidence level of 95%. This study shows that the best variables correlated with consumption are the degree-days for 58% of buildings and the average temperature for the remaining 42%. The savings obtained to date with this third generation network have been significantly higher than the 21% average for 33% of the campus buildings. In the case of 17% of the buildings, there was a significant increase in consumption of 20%, and in the case of the remaining 50% of the buildings, no significant differences were found between consumption before and after installation of district heating.

This paper develops an energy analysis for an existing near Zero Energy (nZEB) and Zero Carbon Emissions building called LUCIA, located at the university campus in Valladolid (Spain). It is designed to supply electricity, cooling and heating needs through solar energy (Photovoltaic Systems, PV), biomass and an Earth–Air Heat Exchanger (EAHE), besides a Combined Heat Power (CHP). It is currently among the top three buildings with the highest LEED certification in the World. The building model is simulated with DesignBuilder version 5. The results of the energy analysis illustrate the heating, cooling and lighting consumptions expected, besides other demands and energy uses. From this data, we carried out an energy balance of the nZEB, which will help to plan preventive actions when compared to the actual energy consumptions, improving the management and control of both the building and its systems. The primary energy indicator obtained is 67 kWh/m2 a year, and 121 kWh/m2 a year for renewable energy generation, with respect to 55 kWh/m2 and 45 kWh/m2 set as reference in Europe. The Renewable Energy Ratio (RER) is 0.66. These indicators become a useful tool for the energy analysis of the nZEB according to the requirements in the European regulations and for its comparison with further nZEB.

Among solar thermal technologies for indoor heating, solar air heaters (SAH) are appealing for implementation on existing buildings due to their simplicity, fewer risks related to the working fluid, and possible independence from the building structure. However, existing research work mainly focuses on winter use and still fails in providing effective solutions for yearly operation, which would enhance their interest. With the aim of analysing an alternative summer use, this work firstly characterises a double channel-single pass solar air collector through experimentation. From the obtained results, modelling and simulation tasks have been conducted to evaluate the possibilities of using hot air, provided by the SAH, while operating under summer conditions within a closed loop, to feed an air-to-water heat exchanger for domestic hot water (DHW) production. The system is studied through simulation under two different configurations for a case study in Valladolid (Spain), during the period from May to September for different airflows in the closed loop. Results show that daily savings can vary from 27% to 85% among the different operating conditions; a configuration where make-up water is fed to the heat exchanger being preferable, with a dedicated water tank for the solar heated water storage of the minimum possible volume. The more favourable results for the harshest months highlight the interest of extending the use of the solar air heaters to the summer period.

Se realiza la caracterización energética de un sistema mixto de recuperación de energía del aire de extracción de localesclimatizados compuesto por dos recuperadores dispuestos en serie en el conducto de impulsión, recuperadores del tipotubos de calor (Heat Pipe) y evaporativo indirecto de placas. Para ello se desarrolla un programa experimental encaminadoa evaluar la influencia de factores como la temperatura, humedad relativa y caudal del aire exterior, flujo de agua y % derecirculación del aire de retorno sobre las características fundamentales definidas para el sistema mixto: Flujo de calorrecuperado, eficacia térmica y coeficiente de prestaciones.Palabras claves: Recuperación de energía, tubos de calor, humedad relativa, flujo de aire primario,recirculación de aire de retorno._______________________________________________________________________________AbstractThe energetic characterisation of a mixed system of energy recovery from exhaust room air, compound by recuperators oftwo types: heat pipe and indirect evaporative with plates type, have been developed. For this purpose an experimentalprogram has been created to evaluate the influence of different parameters such as: Temperature, Relative Humidity,Primary Air Flow, Water Flow and the Secondary Air Recirculation Ratio on it’s thermal performance.Key words: Energy recovery, heat pipes, relative humidity, primary air flow, secondary air recirculation.

This study explores innovative methodologies for estimating the energy baseline (EnBL) of a university classroom building, emphasizing the critical roles of data quality and model selection in achieving accurate energy efficiency assessments. We compare time series models that are suitable for buildings with limited consumption data with univariate and multivariate regression models that incorporate additional variables, such as weather and occupancy. Furthermore, we investigate the advantages of dynamic simulation using the EnergyPlus engine (V5, USDOE United States) and Design Builder software v7, enabling scenario analysis for various operational conditions. Through a comprehensive case study at the UAO University Campus, we validate our models using daily monitoring data and statistical analysis in RStudio. Our findings reveal that model choice significantly influences energy consumption forecasts, leading to potential overestimations or underestimations of savings. By rigorously assessing statistical validation and error analysis results, we highlight the implications for decarbonization strategies in building design and operation. This research provides a valuable framework for selecting appropriate methodologies for energy baseline estimation, enhancing transparency and reliability in energy performance assessments. These contributions are particularly relevant for optimizing energy use and aligning with regulatory requirements in the pursuit of sustainable building practices.

The study uses four AC technologies to assess the energy performance—this is a case study of an educational building in Barranquilla, Colombia. The building currently has split AC technology high-energy consumers. Therefore, it was necessary to assess a replacement with more efficient technology. Because of the non-seasonal climate in the building location, one month of monitoring of energy consumption was the reference for developing an energy model for the building using EnergyPlus and DesignBuilder software. The model was applied to forecast the building energy performance of our more efficient AC technologies available in the Colombian market, and valuable according to building specifications (Split, VRF, VAV, and Chiller). Results show a reduction in energy consumption of approximately 30% with the technology change and 15% savings in life cycle costs (LCCs), even though the building is already considered to have a low energy consumption according to national regulations. The findings of this study underscore the potential for widespread applicability across all types of buildings, regardless of their energy consumption profile, be it low, medium, or high. This extensive applicability not only highlights the adaptability and versatility of the technology but also underscores its significance in achieving substantial energy savings and cost reductions across the entire building industry, contributing to a more sustainable and economically efficient future.

This research delves into a case study of a photovoltaic (PV) energy community, leveraging empirical data to explore the integration of renewable energy sources and storage solutions. By evaluating energy generation and consumption patterns within real-world energy communities (a nominal generation capacity of 33 kWn) in Gipuzkoa, Spain, from May 2022 to May 2023, this study comprehensively examines operational dynamics and performance metrics. This study highlights the critical role of energy consumption patterns in facilitating the integration of renewable energy sources and underscores the importance of proactive strategies to manage demand fluctuations effectively. Against the backdrop of rising energy costs and environmental concerns, renewable energies and storage solutions emerge as compelling alternatives, offering financial feasibility and environmental benefits within energy communities. This study emphasizes the necessity of research and development efforts to develop efficient energy storage technologies and the importance of economic incentives and collaborative initiatives to drive investments in renewable energy infrastructure. The analyzed results provide valuable insights into operational dynamics and performance metrics, further advancing our understanding of their transformative potential in achieving a sustainable energy future. Specifically, our study suggests that storage capacity should ideally support an average annual capacity of 23%, with fluctuations observed where this capacity may double or reduce to a minimum in certain months. Given the current market conditions, our findings indicate the necessity of significant public subsidies, amounting to no less than 67%, to facilitate the installation of storage infrastructure, especially in cases where initial investments are not covered by the energy community.

Natural ventilation in low-budget elementary schools is the main focus to ensure the health and comfort of its occupants, specifically when looking at the global pandemic related to SARS-COV-2. This paper presents an experimental and novel study of natural ventilation in a public elementary school (Los Zumacales), with a particularly low economic budget. The study was carried out during the winter months of the Covid 19 pandemic. The school is located in the rural area of Castilla y León (North-Western Spain) far from high traffic roads. In this study, a methodology of measuring CO2 concentration was applied in nine classrooms in a school. The experimental study shows the level of natural ventilation in each classroom, expressed in Air Changes per Hour (ACH), using the Decay CO2 concentration method. The method is proven by comparing the experimental values of the obtained ACH with those determined by the most powerful methods to achieve appropriate ventilation levels. Thus, ensuring health protection protocol in rural schools, against the COVID 19 pandemic. Harvard guide and Spanish regulations (RITE), two widely recognized methods have been used together with the experimentally obtained standard by Rey et al. Only one classroom showed a value lower than 3 indicating poor ventilation. In this study, the degree of thermal comfort in the nine classrooms were also analyzed according to the EN15251 standard. An average indoor temperature of approximately 19 °C was obtained, and the relative humidity was stable and correct according to Spanish regulations. In addition, the risk of infection in each classroom was estimated following the international method recommended by the federation of European Heating, Ventilation, and Air Conditioning Associations (REHVA). The probability of infection in all the cases studied was less than 14%. Therefore, this study provides a strong response against infections illnesses, such as Covid 19, in educational buildings where economic budgets of their facilities are low in both, maintenance and investment.

The aim of this study is to calculate the gains of the quantified visually enhanced vestibulo-ocular reflex (qVVOR) and the quantified vestibulo-ocular reflex suppression (qVORS), using a specific system to generate a visual suppression index (SI) in healthy subjects obtained through the gains of qVVOR and qVORS, and to determine the normal values of the index, as well as the influence of age and sex variables on the SI., Methods: This prospective observational clinical study includes 83 healthy subjects who underwent the head impulse and suppression tests (HIMP and SHIMP, respectively), qVVOR, and qVORS tests, all of the vHIT. The sinusoidal tests (qVVOR and qVORS) were conducted at an intended frequency of 0.75 Hz. The gains of these tests were calculated using a system specifically designed for this purpose. A formula for the SI was established using a ratio of the gains from these tests. Two SI values are presented: unilateral, distinct for each direction of head movement, and bilateral, representing the suppression of both sides simultaneously., Results: Mean gains for the qVVORs were 0.981 ± 0.070 and 0.978 ± 0.077 for the rightwards and leftwards qVVORs, respectively. The gains for the suppressed tests were 0.334 ± 0.112 and 0.353 ± 0.110 for the rightwards and leftwards qVORSs, respectively. A difference of 0.05 Hz was observed between the expected (0.75 Hz) and the obtained frequency of head movement, which is statistically significant ( p < 0.001). The SI was 0.342 ± 0.118 for the right side (right SI) and 0.363 ± 0.117 for the left side (left SI). The bilateral SI had a mean value of 0.295 ± 0.104. No significant differences in the SI were noted according to the subject's age. The SI for women was lower than in the case of males., Conclusions: The VVOR/VORS quantification algorithm allows for the reliable calculation of the numerical gain of qVVOR and qVORS with mathematical soundness and consistency of results. Our data support the use of a single or specific measure for direction of head movement; although significant differences exist, these differences are not clinically relevant.

Objective: The objectives of this study were to translate into Spanish, cross-culturally adapt and validate the TFI., Materials and Methods: The TFI questionnaire translated into Spanish (Sp-TFI) and cross-culturally adapted following the published guidelines on cross-cultural adaptation of health questionnaires was evaluated using two indicators. Its internal consistency was assessed with Cronbach's α considering the Tinnitus Handicap Inventory (THI) as the gold standard. Further, its test-retest reliability was assessed with intraclass correlation coefficients (ICCs). ICCs were also calculated for the THI and visual analogue scales (VAS) for tinnitus tested and retested in all participants., Results: The mean age of the 18 participants was 45.77 (SD: 11.87) years; 12 were female (66.67 %) and 6 were male (33.33%). Half of the participants experienced tinnitus in their left ear and half in their right. The mean pure-tone average (PTA) in the affected ear was 29.34 (SD: 8.08) dB-HL. Regarding internal consistency and reliability of the Sp-TFI respectively, Cronbach's α was 0.83 and the ICC type (2,1) was 1 (CI: 0.99-1). Among the variables studied, we found the following independent predictors had statistically significant effects on THI score: sex (p < 0.01), PTA (p = 0.03), overall Sp-TFI score (p = 0.02) and Sp-TFI SL, R and A subscale scores (p = 0.03, p = 0.03, and p < 0.01, respectively)., Conclusion: Based on the internal consistency and reliability results obtained in this study, the cross-culturally adapted Spanish version of the TFI (Sp-TFI) has been validated for use in Spain., Level of Evidence: 2B: Individual cohort study/low-quality randomized control studies., (Copyright © 2023 Sociedad Española de Otorrinolaringología y Cirugía de Cabeza y Cuello. Published by Elsevier España, S.L.U. All rights reserved.)

Objective: Main objectives for this study were to develop a quantification method to obtain a Perez-Rey (PR) score adapted to the VVOR test and to evaluate the correlation of the PR score obtained with quantified VVOR with the PR score of the vHIT test., Methods: A new PR score calculation method for quantified VVOR test was developed using the MATLAB computational software based on saccadic response time latency variability between each head oscillation cycle of the VVOR test. Retrospective correlation between PR scores in VVOR and vHIT tests, performed in the same vHIT testing session for patients with vestibular neuritis and vestibular neurectomy, was performed to correlate new PR (VVOR) score with the classic PR (vHIT) score., Results: Thirty patients were included: 11 post-neurectomy and 19 subacute vestibular neuritis. Pearson's correlation coefficient (R2) for the overall sample was 0.92 (p < 0.001) and 95% confidence interval was 0.85 -0.96. In the linear mixed-effects statistical model developed, only PRVHIT and PRVVOR scores showed statistical association in Wald X2 test (p = 0.008)., Conclusion: The new developed PR score for synchronization measurement of saccadic responses in VVOR testing is a valid method that outputs synchronization values and highly correlates with PR score in vHIT test.

Purpose: Computerized posturography is the gold standard for balance assessment. Because of the great cost and dimensions of commercial equipments, low-cost and portable devices have been developed and validated, such as RombergLab, a software in open source term which works connected with a low-cost force platform. The objective of this study was to obtain normative posturography data using this software., Methods: A multicentric prospective and descriptive study, with 350 healthy participants, was designed. Static postural stability (measured using the modified clinical test of sensory interaction on balance) was evaluated using the software connected to the force platform. Using the confidence ellipse area (CEA) in each condition, global equilibrium score (GES) was calculated and adjusted for significant variable factors using cluster analysis., Results: Mean (SD) GES was 0.72 (0.22). Age (p < 0.01), height (p < 0.01) and recruitment center (p < 0.05) were found as influence factors for GES. Cluster analysis obtained 16 groups stratified by age and height. GES decreases with age and height (p < 0.005). No significant interaction of age nor height was found with GES in these clusters (p > 0.05). After correction for height and age, GES was no longer influenced by the recruitment center (p > 0.05)., Conclusions: With the introduction of the global equilibrium score values of the present study into the software, we consider RombergLab v1.3 a reference posturography tool for healthy individuals. Further studies are needed for validating it as a suitable instrumented test for screening between healthy and pathologic subjects and its reliability over time for the follow-up of patients.

Introduction: This article presents the investigation of the clinical utility of artificial neural networks as an alternative in interpreting vestibular evoked myogenic potential (VEMP)., Methods: We developed an application that incorporates a neural network. This software reproduces and analyses the vestibular potential under study. The software also gives an estimated error for this process., Results: The correlation obtained in this study between the neural network and an experienced human observer was always above 95%., Conclusion: The neural network created offers useful, reliable interpretations of vestibular evoked myogenic potential, in agreement with current clinical parameters., (Copyright © 2010 Elsevier España, S.L. All rights reserved.)

Introduction: The Sensory Organization Test of dynamic posturography allows a reliable assessment of the ability of any given patient to maintain a correct stability when conditions in the visual surrounding and/or support surface are deliberately modified. The results of this test can be analyzed according to the norms of the manufacturer of the device or through the application of specific formulae such as those by Cevette., Objectives: To evaluate if the Cevette formulae distinguish correctly between the normal and vestibular patterns, as well as observing the differences between these two groups of patients (normal and vestibular), obtained either through standardized calculation or by the Cevette formulae. The work has been restricted to patients diagnosed with unilateral Menière's disease who presented an active form of the disease and who had not suffered a recent crisis., Material and Methods: 63 patients were studied who fulfilled the inclusion criteria for this study. A clinical and instrumental audio-vestibular study was carried out. The results of the sensory organization test were analyzed according to the pattern offered by the device and through the application of the Cevette formulae., Results: In 63 patients the pattern obtained was normal or vestibular. In 41 the pattern obtained through one system of analysis or the other coincided but in 22 they did not. The analysis of patients using the Cevette formulae offers a higher capacity for clinical discrimination but is not sensitive to the bias introduced by age; however, combined with the classification offered by the device, it manages to differentiate two populations (normal and vestibular) with a very good audio-vestibular correlation., Conclusion: The combined assessment of the results of the sensory organization test using both the equipment analysis and the Cevette formulae provides much better and real information of clinical differences amongst patients with Menière's disease when the result is normal or of vestibular deficiency., (2009 Elsevier España, S.L. All rights reserved.)

Introduction: An aphysiological pattern in computerized dynamic posturography (CDP) may be produced by numerous causes. We analyze the results obtained in this test by a group of malingering patients., Patients and Method: This study analyzes a particular group of 7 malingerers, ie patients simulating a false and unreal equilibrium disorder, without any a priori awareness of the gain expected from a pathological report. The condition can only be identified with the very complex postural disorder known as "continuous imbalance." We analyze the results of the dynamic posturography test following the diagnostic criteria described by other authors., Results: Of the criteria analyzed, we found Cevette's to be the most frequently positive for our study group., Conclusions: The wide diversity in the criteria used makes it necessary to apply them together, assuming a high level of suspicion and great care in the diagnostic process.

Objectives: To review the clinical and pathological characteristics of upper aerodigestive tract amyloidosis with particular attention to laryngeal amyloidosis. Amyloidosis of the upper aerodigestive tract is relatively rare. The larynx is the most common site of involvement in head and neck isolated amyloidosis and the supraglottic region represents the major site of involvement., Material and Methods: Retrospective review of 6 patients diagnosed with upper aerodigestive tract amyloidosis. Hoarseness and airway compromise were the main presenting symptoms., Results: Laryngeal CO2 laser microsurgery was performed and then we refered the patients to the Medical Deparment seeking for systemic involvement and ENT Clinic follow up., Conclusions: In our experience, laryngeal CO2 laser microsurgery is a succesfull way to treat isolated laryngeal amyloidosis with clinical improvement and low recurrence rates.

Purpose of the Study: To present the cases of two patients that developed unilateral vestibular hypofunction after systemic treatment with ototoxic agents, although they manifested symptoms more typical of bilateral vestibular hypofunction., Material and Methods: The patients were seen after having recovered from their initial illnesses, and both of them denied suffering any spells of vertigo, loss of hearing during the treatment or tinnitus., Results: In both patients, oscillopsia and vestibular ataxia were of varying intensity. Bedside vestibular examination, caloric and rotatory chair testing, and vestibular evoked myogenic potentials were congruent with a complete unilateral loss of vestibular function. Audiometry was normal in one case whereas in the other, there was a moderate bilateral sensorineural loss of hearing that was present before treatment and that did not change during the course of the treatment., Conclusion: The existence of unilateral vestibular loss was an unsuspected finding but after careful bedside examination, it was confirmed through extensive vestibular testing. However, this infrequent finding responded very well to vestibular rehabilitation. Different mechanisms are proposed to explain this phenomenon, although there is still no clear evidence of which may account for the responses observed.