Detecting Fall Risk and Frailty in Elders with Inertial Motion Sensors: A Survey of Significant Gait Parameters.

In the elderly, geriatric problems such as the risk of fall or frailty are a challenge for society. Patients with frailty present difficulties in walking and higher fall risk. The use of sensors for gait analysis allows the detection of objective parameters related to these pathologies and to make an early diagnosis. Inertial Measurement Units (IMUs) are wearables that, due to their accuracy, portability, and low price, are an excellent option to analyze human gait parameters in health-monitoring applications. Many relevant gait parameters (e.g., step time, walking speed) are used to assess motor, or even cognitive, health problems in the elderly, but we perceived that there is not a full consensus on which parameters are the most significant to estimate the risk of fall and the frailty state. In this work, we analyzed the different IMU-based gait parameters proposed in the literature to assess frailty state (robust, prefrail, or frail) or fall risk. The aim was to collect the most significant gait parameters, measured from inertial sensors, able to discriminate between patient groups and to highlight those parameters that are not relevant or for which there is controversy among the examined works. For this purpose, a literature review of the studies published in recent years was carried out; apart from 10 previous relevant reviews using inertial and other sensing technologies, a total of 22 specific studies giving statistical significance values were analyzed. The results showed that the most significant parameters are double-support time, gait speed, stride time, step time, and the number of steps/day or walking percentage/day, for frailty diagnosis. In the case of fall risk detection, parameters related to trunk stability or movements are the most relevant. Although these results are important, the total number of works found was limited and most of them performed the significance statistics on subsets of all possible gait parameters; this fact highlights the need for new frailty studies using a more complete set of gait parameters.

Improving the Accuracy of Decawave's UWB MDEK1001 Location System by Gaining Access to Multiple Ranges.

The location of people, robots, and Internet-of-Things (IoT) devices has become increasingly important. Among the available location technologies, solutions based on ultrawideband (UWB) radio are having much success due to their accuracy, which is ideally at a centimeter level. However, this accuracy is degraded in most common indoor environments due to the presence of obstacles which block or reflect the radio signals used for ranging. One way to circumvent this difficulty is through robust estimation algorithms based on measurement redundancy, permitting to minimize the effect of significantly erroneous ranges (outliers). This need for redundancy often conflicts with hardware restraints put up by the location system's designers. In this work, we present a procedure to increase the redundancy of UWB systems and demonstrate it with the help of a commercial system made by Decawave. This system is particularly easy to deploy, by configuring a network of beacons (anchors) and devices (tags) to be located; however, its architecture presents a major disadvantage as each tag to be located can only measure ranges to a maximum of four anchors. This limitation is embedded in the Positioning and Networking Stack (PANS) protocol designed by Decawave, and therefore is not easy to bypass without a total redesign of the firmware. In this paper, we analyze the strategies that we have been able to identify in order to provide this equipment with multiple range measurements, and thus enable each tag to be positioned with more than four measured ranges. We will see the advantages and disadvantages of each of these strategies, and finally we will adopt a solution that we implemented to be able to measure up to eight ranges for each mobile device (tag). This solution implies the duplication of the tags at the mobile user, and the creation of a double interleaved network of anchors. The range among tags and the eight beacons is obtained through an API via a wireless BLE protocol at a 10 Hz rate. A robustified Extended Kalman filter (EKF) is designed to estimate, by trilateration, the position of the pair of mobile tags, using eight ranges. Two different scenarios are used to make localization experimentation: a laboratory and an apartment. Our position estimation, which exploits redundant information and performs outlier removal, is compared with the commercial solution limited to four ranges, demonstrating the need and advantages of our multi-range approach.

Lifetime Victimization in Children and Adolescents With ADHD.

The objective of this study is to describe the frequency and type of victimization in a Spanish child and adolescent clinical ADHD sample and to analyze the association between the types of victimization and the severity of the symptoms. The sample is composed of 106 outpatients in treatment for ADHD, according to Diagnostic and Statistical Manual of Mental Disorders (4th ed.; DSM-IV) criteria. Symptom severity was measured by the Conners-3 scales. ADHD and comorbid diagnostics were evaluated with the Mini-Kid interview. The victimization experiences were studied using the Juvenile Victimization Questionnaire (JVQ). Children with child maltreatment history showed a greater intensity of hyperactivity/impulsivity, aggression and behavioral disorders as well as depression and anxiety disorders. The presence of peer victimization was associated with inattention, learning disorders, executive functioning, and relationship problems. Episodes of victimization should be considered in the treatment of the ADHD. Child maltreatment history is more associated with hyperactivity-impulsivity symptoms, while peer victimization is more associated with attentional symptoms.

Emotional regulation for adolescents: a group-based treatment pilot study through the STEPPS programme.

BACKGROUND: Borderline personality disorder (BPD) usually begins in adolescence and manifests itself in adult life. Early intervention can improve the prognosis or reduce its severity. Nevertheless, there are currently few studies of adolescent patients with severe emotion instability and borderline personality traits. AIMS: To evaluate the effectiveness of the Systems Training for Emotional Predictability and Problem Solving (STEPPS) programme in a sample of 21 adolescents (aged 13-17 years) in the Child and Adolescents Mental Health Center of Tarragona in Spain. METHOD: We evaluated BPD traits using the Diagnostic Interview for Borderline Disorder-Revised (DIB-R) and the Global Clinical Impression Scale of Illness Severity for TLP (CGI-TLP). We compared pre- and post-treatment scores for the DIB-R, CGI-GI scale, general psychopathology using the Personality Inventory for Adolescents (PAI-A) and impulsivity with the Barratt Impulsivity Scale (BIS-11). The therapeutic objectives were evaluated with the Borderline Estimate Severity over Time (BEST) scale. RESULTS: There was a statistically significant improvement in the scores for the affective area and in the total score of the DIB-R, a decrease in the percentage of patients who failed to meet criteria for BPD, and an improvement (although not statistically significant) in the scores of the BEST scale throughout the treatment. The results of the CGI-GI scale showed global improvement in almost 72% of patients. CONCLUSION: Our study suggests that STEPPS can be an effective treatment to improve BPD symptoms and is very useful in community settings with limited resources in which efficient treatment alternatives must be sought. However, this conclusion must be interpreted with caution, as there is no comparison control group.

Liraglutide vs. lixisenatide in obese type 2 diabetes mellitus patients: What effect should we expect in routine clinical practice?

AIM: Liraglutide and lixisenatide improved glycemic control, weight and cardiovascular risk factors (CVRF) in type 2 diabetes mellitus (T2DM) patients. Our objective was to analyze clinical efficacy and safety differences in routine clinical practice. METHODS: A 24-week prospective observational study to compare the effect of liraglutide versus lixisenatide in obese T2DM patients in routine clinical practice. The main objective was to analyze between-group glycosylated hemoglobin (HbA1c) differences at the end of the study. Secondary objectives included differences in body weight, other CVRF, changes in medication, side effects, satisfaction and safety. RESULTS: A total of 100 patients (50 liraglutide, 50 lixisenatide) were included. Both groups experienced a decrease in HbA1c values (liraglutide, -1.4%, CI 95% -2, -0.8, P < 0.001 vs. lixisenatide, -0.8%, 95% CI -1.2, -0.5, P < 0.001). No differences were found in final HbA1c values between both groups (liraglutide 7.3 ±â€¯0.9% vs. lixisenatide 7.2 ±â€¯1.5%, P = 0.7). We did not detect between groups differences in anthropometric variables or CVRF at the study end. A lower proportion of patients received treatment with a maximum dose of liraglutide compared with lixisenatide (27% vs. 95%, P < 0.001). In contrast, a greater percentage of patients in the lixisenatide group than in liraglutide group (29% vs. 9%, P = 0.026) intensified treatment by the addition of sodium-glucose transporter type 2 inhibitors. Adverse events were less frequently reported in liraglutide treated patients compared with lixisentatide (80% vs. 96%, P = 0.014). No serious adverse events were detected. CONCLUSIONS: These results confirm the efficacy and safety of liraglutide and lixisenatide in routine clinical practice. Moreover, a different therapeutic effect between liraglutide and lixisenatide was detected.

Vaccination adherence to influenza, pneumococcal and hepatitis B virus in adult type 1 diabetes mellitus patients.

AIM: To document adherence to influenza, pneumococcal and hepatitis B virus (HBV) vaccination programme in adult type 1 diabetes mellitus (T1DM) patients. MATERIALS AND METHODS: Observational retrospective study using data obtained from computerized clinical records. We contacted all adult T1DM registered in our database from a tertiary diabetes care hospital. Primary efficacy outcome was to describe influenza, pneumococcal and HBV vaccination status. RESULTS: Three hundred patients were analyzed (male 53%). Mean age was 40.0±14.4years and T1DM duration was 19.7±11.8years. Thirty-five percent of the patients had complementary indications for studied vaccines. Adherence to vaccination program for influenza, pneumococcal and HBV was achieved by 55%, 18% and 17% of the patients, respectively. Only 3% of the subjects were vaccinated against the three microorganisms. Predictor of correct vaccination were: age, shorter diabetes duration, insulin pump treatment, better diabetes control and being a health professional. We detected 17 sick leaves, 127 lost working days and 3 hospitalizations due to flue during the follow-up. CONCLUSIONS: The uptake of recommended vaccinations against influenza, pneumococcal and HBV in adult T1DM patients was below desirable levels. A special effort is required to all health professionals to implement immunization among adult people with T1DM. Clinical Trials NCT03478254.

GNSS Trajectory Anomaly Detection Using Similarity Comparison Methods for Pedestrian Navigation.

The urban setting is a challenging environment for GNSS receivers. Multipath and other anomalies typically increase the positioning error of the receiver. Moreover, the error estimate of the position is often unreliable. In this study, we detect GNSS trajectory anomalies by using similarity comparison methods between a pedestrian dead reckoning trajectory, recorded using a foot-mounted inertial measurement unit, and the corresponding GNSS trajectory. During a normal walk, the foot-mounted inertial dead reckoning setup is trustworthy up to a few tens of meters. Thus, the differing GNSS trajectory can be detected using form similarity comparison methods. Of the eight tested methods, the Hausdorff distance (HD) and the accumulated distance difference (ADD) give slightly more consistent detection results compared to the rest.

Off-Line Evaluation of Mobile-Centric Indoor Positioning Systems: The Experiences from the 2017 IPIN Competition.

The development of indoor positioning solutions using smartphones is a growing activity with an enormous potential for everyday life and professional applications. The research activities on this topic concentrate on the development of new positioning solutions that are tested in specific environments under their own evaluation metrics. To explore the real positioning quality of smartphone-based solutions and their capabilities for seamlessly adapting to different scenarios, it is needed to find fair evaluation frameworks. The design of competitions using extensive pre-recorded datasets is a valid way to generate open data for comparing the different solutions created by research teams. In this paper, we discuss the details of the 2017 IPIN indoor localization competition, the different datasets created, the teams participating in the event, and the results they obtained. We compare these results with other competition-based approaches (Microsoft and Perf-loc) and on-line evaluation web sites. The lessons learned by organising these competitions and the benefits for the community are addressed along the paper. Our analysis paves the way for future developments on the standardization of evaluations and for creating a widely-adopted benchmark strategy for researchers and companies in the field.

Smartphone-Based Cooperative Indoor Localization with RFID Technology.

In GPS-denied indoor environments, localization and tracking of people can be achieved with a mobile device such as a smartphone by processing the received signal strength (RSS) of RF signals emitted from known location beacons (anchor nodes), combined with Pedestrian Dead Reckoning (PDR) estimates of the user motion. An enhacement of this localization technique is feasible if the users themselves carry additional RF emitters (mobile nodes), and the cooperative position estimates of a group of persons incorporate the RSS measurements exchanged between users. We propose a centralized cooperative particle filter (PF) formulation over the joint state of all users that permits to process RSS measurements from both anchor and mobile emitters, as well as PDR motion estimates and map information (if available) to increase the overall positioning accuracy, particularly in regions with low density of anchor nodes. Smartphones are used as a convenient mobile platform for sensor measurements acquisition, low-level processing, and data transmission to a central unit, where cooperative localization processing takes place. The cooperative method is experimentally demonstrated with four users moving in an area of 1600 m 2 , with 7 anchor nodes comprised of active RFID (radio frequency identification) tags, and additional mobile tags carried by each user. Due to the limited coverage provided by the anchor beacons, RSS-based individual localization is inaccurate (6.1 m median error), but this improves to 4.9 m median error with the cooperative PF. Further gains are produced if the PDR information is added to the filter: median error of 3.1 m (individual) and 2.6 m (cooperative); and if map information is also considered, the results are 1.8 m (individual) and 1.6 m (cooperative). Thus, for each version of the particle filter, cooperative localization outperforms individual localization in terms of positioning accuracy.

Comparing the Performance of Indoor Localization Systems through the EvAAL Framework.

In recent years, indoor localization systems have been the object of significant research activity and of growing interest for their great expected social impact and their impressive business potential. Application areas include tracking and navigation, activity monitoring, personalized advertising, Active and Assisted Living (AAL), traceability, Internet of Things (IoT) networks, and Home-land Security. In spite of the numerous research advances and the great industrial interest, no canned solutions have yet been defined. The diversity and heterogeneity of applications, scenarios, sensor and user requirements, make it difficult to create uniform solutions. From that diverse reality, a main problem is derived that consists in the lack of a consensus both in terms of the metrics and the procedures used to measure the performance of the different indoor localization and navigation proposals. This paper introduces the general lines of the EvAAL benchmarking framework, which is aimed at a fair comparison of indoor positioning systems through a challenging competition under complex, realistic conditions. To evaluate the framework capabilities, we show how it was used in the 2016 Indoor Positioning and Indoor Navigation (IPIN) Competition. The 2016 IPIN competition considered three different scenario dimensions, with a variety of use cases: (1) pedestrian versus robotic navigation, (2) smartphones versus custom hardware usage and (3) real-time positioning versus off-line post-processing. A total of four competition tracks were evaluated under the same EvAAL benchmark framework in order to validate its potential to become a standard for evaluating indoor localization solutions. The experience gained during the competition and feedback from track organizers and competitors showed that the EvAAL framework is flexible enough to successfully fit the very different tracks and appears adequate to compare indoor positioning systems.

The Smartphone-Based Offline Indoor Location Competition at IPIN 2016: Analysis and Future Work.

This paper presents the analysis and discussion of the off-site localization competition track, which took place during the Seventh International Conference on Indoor Positioning and Indoor Navigation (IPIN 2016). Five international teams proposed different strategies for smartphone-based indoor positioning using the same reference data. The competitors were provided with several smartphone-collected signal datasets, some of which were used for training (known trajectories), and others for evaluating (unknown trajectories). The competition permits a coherent evaluation method of the competitors' estimations, where inside information to fine-tune their systems is not offered, and thus provides, in our opinion, a good starting point to introduce a fair comparison between the smartphone-based systems found in the literature. The methodology, experience, feedback from competitors and future working lines are described.

Importancia de la detección del trastorno por déficit de atención/hiperactividad en el adulto / Importance of screening attention deficit hyperactivity disorder in adults

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Improving inertial Pedestrian Dead-Reckoning by detecting unmodified switched-on lamps in buildings.

This paper explores how inertial Pedestrian Dead-Reckoning (PDR) location systems can be improved with the use of a light sensor to measure the illumination gradients created when a person walks under ceiling-mounted unmodified indoor lights. The process of updating the inertial PDR estimates with the information provided by light detections is a new concept that we have named Light-matching (LM). The displacement and orientation change of a person obtained by inertial PDR is used by the LM method to accurately propagate the location hypothesis, and vice versa; the LM approach benefits the PDR approach by obtaining an absolute localization and reducing the PDR-alone drift. Even from an initially unknown location and orientation, whenever the person passes below a switched-on light spot, the location likelihood is iteratively updated until it potentially converges to a unimodal probability density function. The time to converge to a unimodal position hypothesis depends on the number of lights detected and the asymmetries/irregularities of the spatial distribution of lights. The proposed LM method does not require any intensity illumination calibration, just the pre-storage of the position and size of all lights in a building, irrespective of their current on/off state. This paper presents a detailed description of the light-matching concept, the implementation details of the LM-assisted PDR fusion scheme using a particle filter, and several simulated and experimental tests, using a light sensor-equipped Galaxy S3 smartphone and an external foot-mounted inertial sensor. The evaluation includes the LM-assisted PDR approach as well as the fusion with other signals of opportunity (WiFi, RFID, Magnetometers or Map-matching) in order to compare their contribution in obtaining high accuracy indoor localization. The integrated solution achieves a localization error lower than 1 m in most of the cases.

Do firstborn children have an increased risk of ADHD?

OBJECTIVE: Although previous reports have found no birth-order influence on ADHD risk, the authors hypothesize that being the firstborn is a risk factor for developing ADHD. METHOD: They selected all of the currently treated ADHD outpatients (n = 748) from our database. Families with adopted sons, nonnuclear families, and families with only one child and with sons (affected or unaffected) younger than 6 or older than 18 years were excluded. A total of 181 families with 213 ADHD sons met the inclusion criteria. We used all siblings without a clinical diagnosis of ADHD and who had no contact with our service as our unaffected controls (n = 173). RESULTS: The bivariate analysis showed that ADHD was associated with birth order and that firstborn children had nearly twice the ADHD risk of children with other birth orders. CONCLUSION: birth order can be an ADHD risk factor in clinical samples.

[Satisfaction and quality of life evaluation in patients with type 1 diabetes mellitus treated using continuous subcutaneous insulin infusion compared with multiple daily injections]. / Valoración de la satisfación y calidad de vida en pacientes con diabetes mellitus tipo 1 en tratamiento con infusión subcutánea continua de insulina comparado con multidosis de insulina.

OBJECTIVE: To assess the quality of life (QOL) and satisfaction (SF) in patients with type 1 diabetes mellitus (T1DM) treated with continuous subcutaneous insulin infusion (CSII) compared with multiple daily insulin injections (MDI). METHOD: A descriptive study was conducted to assess the QOL and SF of 68 patients on CSII or MDI treatment (1:2). The instruments used were, the Spanish version of the Diabetes Quality of Life (EsDQOL) specific for diabetes related QOL, SF-36 for general QOL, and the Diabetes Treatment Satisfaction Questionnaire (DTSQ) for SF evaluation. RESULTS: The EsDQOL scores for patients on CSII therapy were similar to those treated with MDI (87.20±21.11 vs 86.83±20.7, P=.86), with lower scores in the SF-36 questionnaire (66.91±15.76 vs 75.90±14.56, P=.03) except in Health Transition section, where patients treated with CSII showed higher scores (68.75±19.66 vs 57.93±17.18, p=.02). The values obtained in the DTSQ questionnaire were higher in CSII patients compared with the MDI group in last weeks (31.50±4.66 vs 27.83±6.06, p=.01) and last three months periods (13.2±6.73 vs 8.77±7.40, p=.01). CONCLUSIONS: Patients with T1DM on CSII therapy showed a poorer global QOL, although they felt more satisfied with their treatment than those treated with MDI. No differences in diabetes related QOL were detected between groups.

Valoración de la satisfación y calidad de vida en pacientes con diabetes mellitus tipo 1 en tratamiento con infusión subcutánea continua de insulina comparado con multidosis de insulina / Satisfaction and quality of life evaluation in patients with type 1 diabetes mellitus treated using continuous subcutaneous insulin infusion compared with multiple daily injections

Valorar la calidad de vida ( CV ) y satisfacción (SF) de los pacientes con diabetes mellitus tipo 1 (DM1) en terapia con infusión subcutánea continua de insulina (ISCI) comparado con los pacientes tratados con multidosis diarias de insulina (MDI). Método Estudio descriptivo valorando la CV y SF de 68 pacientes en tratamiento con ISCI o MDI (1:2). Los instrumentos utilizados fueron la versión española del cuestionario de CV relacionado con diabetes (Diabetes Quality of Life [EsDQOL]) y el cuestionario general de CV SF-36, junto con el test de SF con el tratamiento recibido (Diabetes Treatment Satisfaction Questionnaire [DTSQ]). Resultado sLos pacientes en terapia ISCI obtuvieron una puntuación similar a los tratados con MDI en el cuestionario EsDQOL (87,20 ± 21,11 y 86,83 ± 20,78, p = 0,86, respectivamente), aunque mostraron resultados menores en el test SF-36 (66,91 ± 15,76 y 75,90 ± 14,56 p = 0,03, respectivamente) salvo en el apartado transición de salud de este último, que resultó mayor (68,75 ± 19,66 y 57,93 ± 17,18 p = 0,02, respectivamente). Los valores conseguidos en el cuestionario DTSQ fueron mayores en el grupo ISCI frente a MDI en las últimas semanas (31,50 ± 4,66 y 27,83 ± 6,06, p = 0,01, respectivamente) y en los últimos 3 meses (13,20 ± 6,73 y 8,77 ± 7,40, p = 0,01, respectivamente). Conclusiones Los pacientes con DM1 en terapia ISCI mostraron peor CV general aunque se sienten más satisfechos con su tratamiento que los tratados con MDI. No detectamos diferencias en la CV relacionada con diabetes entre ambos grupos de tratamiento (AU)

Objective To assess the quality of life (QOL) and satisfaction (SF) in patients with type 1 diabetes mellitus (T1DM) treated with continuous subcutaneous insulin infusion (CSII) compared with multiple daily insulin injections (MDI).MethodA descriptive study was conducted to assess the QOL and SF of 68 patients on CSII or MDI treatment (1:2). The instruments used were, the Spanish version of the Diabetes Quality of Life (EsDQOL) specific for diabetes related QOL, SF-36 for general QOL, and the Diabetes Treatment Satisfaction Questionnaire (DTSQ) for SF evaluation. Results The Es DQOL scores for patients on CSII therapy were similar to those treated with MDI (87.20 ± 21.11 vs 86.83 ± 20.7, P = .86), with lower scores in the SF-36 questionnaire (66.91 ± 15.76 vs 75.90 ± 14.56, P = .03) except in Health Transition section, where patients treated with CSII showed higher scores (68.75 ± 19.66 vs 57.93 ± 17.18, p = .02). The values obtained in the DTSQ questionnaire were higher in CSII patients compared with the MDI group in last weeks (31.50 ± 4.66 vs 27.83 ± 6.06, p = .01) and last three months periods (13.2 ± 6.73 vs 8.77 ± 7.40, p = .01). Conclusions Patients with T1DM on CSII therapy showed a poorer global QOL, although they felt more satisfied with their treatment than those treated with MDI. No differences in diabetes related QOL were detected between groups (AU)

Error estimation for the linearized auto-localization algorithm.

The Linearized Auto-Localization (LAL) algorithm estimates the position of beacon nodes in Local Positioning Systems (LPSs), using only the distance measurements to a mobile node whose position is also unknown. The LAL algorithm calculates the inter-beacon distances, used for the estimation of the beacons' positions, from the linearized trilateration equations. In this paper we propose a method to estimate the propagation of the errors of the inter-beacon distances obtained with the LAL algorithm, based on a first order Taylor approximation of the equations. Since the method depends on such approximation, a confidence parameter τ is defined to measure the reliability of the estimated error. Field evaluations showed that by applying this information to an improved weighted-based auto-localization algorithm (WLAL), the standard deviation of the inter-beacon distances can be improved by more than 30% on average with respect to the original LAL method.

PDR with a foot-mounted IMU and ramp detection.

The localization of persons in indoor environments is nowadays an open problem. There are partial solutions based on the deployment of a network of sensors (Local Positioning Systems or LPS). Other solutions only require the installation of an inertial sensor on the person's body (Pedestrian Dead-Reckoning or PDR). PDR solutions integrate the signals coming from an Inertial Measurement Unit (IMU), which usually contains 3 accelerometers and 3 gyroscopes. The main problem of PDR is the accumulation of positioning errors due to the drift caused by the noise in the sensors. This paper presents a PDR solution that incorporates a drift correction method based on detecting the access ramps usually found in buildings. The ramp correction method is implemented over a PDR framework that uses an Inertial Navigation algorithm (INS) and an IMU attached to the person's foot. Unlike other approaches that use external sensors to correct the drift error, we only use one IMU on the foot. To detect a ramp, the slope of the terrain on which the user is walking, and the change in height sensed when moving forward, are estimated from the IMU. After detection, the ramp is checked for association with one of the existing in a database. For each associated ramp, a position correction is fed into the Kalman Filter in order to refine the INS-PDR solution. Drift-free localization is achieved with positioning errors below 2 meters for 1,000-meter-long routes in a building with a few ramps.

Airborne ultrasonic vortex generation using flexible ferroelectrets.

Cellular ferroelectrets exhibit interesting electromechanical- acoustical characteristics. Their recent appearance and remarkable properties open up new possibilities for the design and development of ultrasonic transducers. In particular, the feasibility of fabricating ultrasonic vortex generators using ferroelectret films is demonstrated in this work. To this end, a transducer prototype was built by gluing the material onto a tangential-helical surface (outer diameter: 40 mm, pitch: 3.45 mm). Experimental results agree well with the theoretical estimation of the pressure and phase of the acoustic field in the near field and far field, which corroborates the potential of ferroelectrets to customize special acoustic fields. Furthermore, the proposed fabrication procedure is inexpensive and represents a new alternative for exploring and analyzing the special characteristics of acoustical helical wavefronts.