Pulmonary manifestations in a cohort of patients with inborn errors of immunity: an 8-year follow-up study.

BACKGROUND: Inborn errors of immunity (IEIs) are a group of congenital diseases caused by genetic defects in the development and function of the immune system. The involvement of the respiratory tract is one of the most common presentations in IEIs. METHODS: Overall, 117 patients with diagnosed IEIs were followed-up within 8 years at the National Research Institute of Tuberculosis and Lung Diseases (NRITLD). Demographic, clinical, and laboratory data were collected in a questionnaire. Pulmonary function test (PFT), chest X-ray (CXR), and high-resolution computed tomography (HRCT) scans were obtained where applicable. RESULTS: Our study population consisted of 48 (41%) patients with predominantly antibody deficiencies (PADs), 39 (32%) patients with congenital defects of phagocytes, 14 (11.9%) patients with combined immunodeficiency (CID), and 16 (14%) patients with Mendelian susceptibility to mycobacterial diseases (MSMD). . Recurrent pneumonia was the most common manifestation, while productive cough appeared to be the most common symptom in almost all diseases. PFT showed an obstructive pattern in patients with PAD, a restrictive pattern in patients with CID, and a mixed pattern in patients with CGD. HRCT findings were consistent with bronchiectasis in most PAD patients, whereas consolidation and mediastinal lesions were more common in the other groups. CONCLUSIONS: Pulmonary manifestations vary among different groups of IEIs. The screening for lung complications should be performed regularly to reveal respiratory pathologies in early stages and follow-up on already existing abnormalities.

Evaluation of the Effects of PAKDAM, an Invented Device to Get Nitrous Oxide and Oxygen, in the Consumers: A Report of Pilot Study.

Background: Since last decade, a device called PAKDAM (means clean inspiration) was invented in Iran which has been used in some cafe to prepare N2O and O2 as a new instrument instead of using water pipe. This study aimed to evaluate the respiratory and health effects of Pakdam and investigate its short and midterm side effects in users. Materials and Methods: In a case-control pilot study between September 2021 and March 2022, 152 individuals were divided into two groups: 76 consumers (case) and 76 non- consumers (control). Both groups were divided into two groups of 36 smokers and 36 non-smokers. Participants signed the participation form and filled out the demographic data questionnaire, and then their vital signs, O2 saturation, expiratory CO, and spirometry tests were recorded. Results: The subjects who used the device had a mean blood pressure of 123.71±16.11 mmHg, oxygen saturation of 97.2±1.9, exhaled carbon monoxide of 9.8±5.5, and an FVC / FEV1 ratio of 88.5±7.9. These figures in control group were (137.79±18.15) - (94.1±4.2) - (14.3 ± 9.3) and (83.9 ± 10.4), respectively. In addition to the effects on the respiratory system, consumers had lower heart rates and lower systolic and diastolic blood pressures. Conclusion: The blood oxygen level and FEV1/FVC ratio were higher in subjects using Pakdam and the amount of exhaled carbon monoxide and blood pressure were lower. This condition was more common in smokers and less in non-smokers. It is possible to see the favorable effects of using Pakdam device on people especially in smokers.

Iranian clinical practice guideline for amyotrophic lateral sclerosis.

Amyotrophic lateral sclerosis (ALS) is a rapidly progressive neurodegeneration involving motor neurons. The 3-5 years that patients have to live is marked by day-to-day loss of motor and sometimes cognitive abilities. Enormous amounts of healthcare services and resources are necessary to support patients and their caregivers during this relatively short but burdensome journey. Organization and management of these resources need to best meet patients' expectations and health system efficiency mandates. This can only occur in the setting of multidisciplinary ALS clinics which are known as the gold standard of ALS care worldwide. To introduce this standard to the care of Iranian ALS patients, which is an inevitable quality milestone, a national ALS clinical practice guideline is the necessary first step. The National ALS guideline will serve as the knowledge base for the development of local clinical pathways to guide patient journeys in multidisciplinary ALS clinics. To this end, we gathered a team of national neuromuscular experts as well as experts in related specialties necessary for delivering multidisciplinary care to ALS patients to develop the Iranian ALS clinical practice guideline. Clinical questions were prepared in the Patient, Intervention, Comparison, and Outcome (PICO) format to serve as a guide for the literature search. Considering the lack of adequate national/local studies at this time, a consensus-based approach was taken to evaluate the quality of the retrieved evidence and summarize recommendations.

Beneficial effects of the combination of BCc1 and Hep-S nanochelating-based medicines on IL-6 in hospitalized moderate COVID-19 adult patients: a randomized, double-blind, placebo-controlled clinical trial.

BACKGROUND: In the severe forms of COVID-19 and many other infectious diseases, the patients develop a cytokine storm syndrome (CSS) where pro-inflammatory cytokines such as IL-6 and TNF-α play a key role in the development of this serious process. Selenium and iron are two important trace minerals, and their metabolism is tightly connected to immune system function. Numerous studies highlight the role of selenium and iron metabolism changes in the procedure of COVID-19 inflammation. The immunomodulator effect of nanomedicines that are synthesized based on nanochelating technology has been proved in previous studies. In the present study, the effects of the combination of BCc1(with iron-chelating property) and Hep-S (containing selenium) nanomedicines on mentioned cytokines levels in hospitalized moderate COVID-19 patients were evaluated. METHODS: Laboratory-confirmed moderate COVID-19 patients were enrolled to participate in a randomized, double-blind, placebo-controlled study in two separate groups: combination of BCc1 and Hep-S (N = 62) (treatment) or placebo (N = 60) (placebo). The blood samples were taken before medications on day zero, at discharge, and 28 days after consumption to measure hematological and biochemical parameters and cytokine levels. The clinical symptoms of all the patients were recorded according to an assessment questionnaire before the start of the treatment and on days 3 and discharge day. RESULTS: The results revealed that consumption of the nanomedicines led to a significant decrease in the mean level of IL-6 cytokine, and at the end of the study, there was a 77% downward trend in IL-6 in the nanomedicine group, while an 18% increase in the placebo group (p < 0.05). In addition, the patients in the nanomedicines group had lower TNF-α levels; accordingly, there was a 21% decrease in TNF-α level in the treatment group, while a 31% increase in this cytokine level in the placebo was observed (p > 0.05). On the other hand, in nanomedicines treated groups, clinical scores of coughing, fatigue, and need for oxygen therapy improved. CONCLUSIONS: In conclusion, the combination of BCc1 and Hep-S inhibits IL-6 as a highly important and well-known cytokine in COVID-19 pathophysiology and presents a promising view for immunomodulation that can manage CSS. TRIAL REGISTRATION: Iranian Registry of Clinical Trials RCT20170731035423N2 . Registered on June 12, 2020.

COVID-19 Associated Unilateral Diaphragm Paralysis: A Case Report.

Diaphragm paralysis may be either idiopathic or associated with several medical conditions including viral and bacterial infection. The association of phrenic nerve palsy with viral infections is rare but well-appreciated in several case reports. Neuropathy, both central and peripheral, is a common neurological consequence of COVID-19. Here, we describe a case of diaphragm paralysis in a woman who was admitted to the hospital because of COVID-19 pneumonia. Post-COVID-19 unilateral paralyzed diaphragm was diagnosed with a chest X-ray for her and the disorder was attributed to COVID-19 because no other etiology was found to be associated. So far, phrenic neuropathy and diaphragmatic paralysis in a COVID-19-affected patient have not been reported from Iran.

Role of Inspiratory Muscle Training on Pulmonary Rehabilitation in Patients with COVID-19: A Pilot Study.

Background: Inspiratory muscle training has been introduced as one of the effective methods in pulmonary rehabilitation, and attention to this technique in patients with COVID-19 is still being studied. Materials and Methods: In the present study 52 patients who have undergone the period of the COVID-19 disease were randomly divided into two groups. In the control group, in addition to the routine treatment prescribed by a specialist physician, rehabilitation was performed by performing diaphragmatic breathing exercises, pursed-lips breathing, chest expansion, and simple stretching exercises. In the intervention group in addition to the rehabilitation program provided to the control group, patients used an inspiratory muscle training device. This pulmonary rehabilitation program was performed twice a day and 30 repetitions each time with a two-minute rest after every 10 exercises. After 4 weeks, patients in both groups were referred to the hospital for reassessment of the distance of the 6-minute walk test, SF-12 questionnaire results, dyspnea, and S-index. To compare quantitative variables between the two groups we utilized a student t-test. Type one error was put at P≤0.05. Results: The comparison of 6MWT values shows that the mean of this index in the intervention group is significantly higher than the control group (p = 0.002). Also, the S-index of the two groups showed a significant difference (p=0.024). Results show a significant increase in the SF-12 quality of life questionnaire in patients using IMT (p=0.001). Conclusion: IMT improves pulmonary functions, 6MWT, and SF-12 Questionnaire in recovered COVID-19 patients.

Uncommon Complications of Lung Transplantation in a Referral Center.

Background: Many efforts were made to determine the uncommon clinical complications after lung transplantation and treatment options to tackle them; however, many of these rare complications have not been mentioned in recent publications. Evaluating and recording adverse effects after organ transplantation can significantly prevent post-transplant mortality. This study aimed to examine rejection factors by examining individuals undergoing lung transplantation surgery. Materials and Methods: In a prospective longitudinal study, we followed up on complications of 60 lung recipients post lung-transplantation surgery for six years from 2010 to 2018. All complications were recorded in follow-up visits or hospital admissions during these years. Finally, the patients' information was categorized and evaluated by designing a questionnaire. Results: From a total of 60 transplant recipients, from 2010 to 2018, 58 patients were initially enrolled in our study, but two were lost to follow-up. Uncommon complications witnessed in the post-transplantation period included endogenous endophthalmitis, herpetic keratitis, duodenal strongyloidiasis, intestinal cryptosporidiosis, myocardial infarction, diaphragm dysfunction, Chylothorax, thyroid nodule, and necrotizing pancreatitis. Conclusion: Meticulous postoperative surveillance is crucial for managing lung transplant patients for early detection and treatment of common and uncommon complications. Therefore, it is necessary to establish procedures for assessing the patients' constancy until complete recovery.

Transmission electron microscopy study of suspected primary ciliary dyskinesia patients.

Primary ciliary dyskinesia (PCD) is a rare autosomal recessive condition often presenting with chronic respiratory infections in early life. Transmission electron microscopy (TEM) is used to detect ciliary ultrastructural defects. In this study, we aimed to assess ciliary ultrastructural defects using quantitative methods on TEM to identify its diagnostic role in confirming PCD. Nasal samples of 67 patients, including 37 females and 30 males (20.3 ± 10.7 years old), with suspected PCD symptoms were examined by TEM. The most common presentations were bronchiectasis: 26 (38.8%), chronic sinusitis: 23 (34.3%), and recurrent lower respiratory infections: 21 (31.3%). Secondary ciliary dyskinesia, including compound cilia (41.4%) and extra-tubules (44.3%), were the most prevalent TEM finding. Twelve patients (17.9%) had hallmark diagnostic criteria for PCD (class 1) consisting of 11 (16.4%) outer and inner dynein arm (ODA and IDA) defects and only one concurrent IDA defect and microtubular disorganization. Also, 11 patients (16.4%) had probable criteria for PCD (class 2), 26 (38.8%) had other defects, and 18 (26.9%) had normal ciliary ultrastructure. Among our suspected PCD patients, the most common ultrastructural ciliary defects were extra-tubules and compound cilia. However, the most prevalent hallmark diagnostic defect confirming PCD was simultaneous defects of IDA and ODA.

National Research Institute of Tuberculosis and Lung Disease (NRITLD) Protocol for the Treatment of Patients with COVID-19.

More than a year after the onset of the coronavirus disease pandemic in 2019, the disease remains a major global health issue. During this time, health organizations worldwide have tried to provide integrated treatment guidelines to control coronavirus disease 2019 (COVID-19) at different levels. However, due to the novel nature of the disease and the emergence of new variants, medical teams' updating medical information and drug prescribing guidelines should be given special attention. This version is an updated instruction of the National Research Institute of Tuberculosis and Lung Disease (NRITLD) in collaboration with a group of specialists from Masih Daneshvari Hospital in Tehran, Iran, which is provided to update the information of caring clinicians for the treatment and care of COVID-19 hospitalized patients.

COVID-19 Reinfection in a Patient with Hodgkin Lymphoma: a Case Report.

COVID-19 pneumonia has invaded the world and continues to expand. The current evidence of the immune system reaction to this viral pneumonia shows that the post-infectious immunity against the virus may be temporary, and the virus may reinfect the patients after healing from the previous one. Here is presented a 55-year-old female patient, as a known case of Hodgkin lymphoma, diagnosed with COVID-19 reinfection during 40 days. Such evidence may be helpful in further understanding the immunology of the disease.

Comparison of high-flow oxygenation with noninvasive ventilation in COPD exacerbation: A crossover clinical trial.

OBJECTIVES: To compare the therapeutic effects of high-flow-oxygen-Therapy (HFT) and noninvasive-ventilation (NIV) for stabilizing chronic obstructive pulmonary disease during exacerbation. METHODS: In this randomized clinical trial at Masih-Daneshvari hospital, between July 2019 and Oct 2019, 30 exacerbated-COPD-patient with PaCO2 64.58 ± 11.61 mm Hg, Respiratory Rate 24.43 ± 2.75, and PH 7.31 ± 0.02 were divided into two groups, N = 15. By a simple randomized allocation, patients receive either NIV or HFT for 1 hour, and following a washout period of 30 minutes, they switched to the other treatment option. Arterial Blood Gas Parameters, as well as Respiratory Rate (RR), Dyspnea Score, Heart Rate (HR), and Oxygen Saturation (SO2 ), were compared before and after the intervention and between groups. RESULTS: Baseline patient characteristics were similar in the two groups. Pre and post-analysis revealed that in both groups, all improved significantly. After the first period, there was no difference in all parameters between groups except for SO2 which was significantly higher in HFT (%92.1 ± 1) than that of NIV (%89 ± 1), P = .001. Likewise, following the washout period, patients in HFT and NIV had a dyspnea score of 1.93 ± 0.7 and 2.73 ± 0.9, respectively, P = .01. No carryover-effect and was observed but the period effect was significant for some outcomes. A significant improvement in SO2 and HR was observed by HFT according to treatment effect by combining two periods' results. During the study, no side effects were reported. CONCLUSION: In this short-term study HFT appears feasible for patients with COPD exacerbation to reduce dyspnea score and improve respiratory distress.

Evaluation of adalimumab effects in managing severe cases of COVID-19: A randomized controlled trial.

BACKGROUND: COVID-19, which is a disease caused by the SARS-CoV-2 virus, has spread around the world since late 2019. Studies have found associations between the rising levels of TNF-α and severe COVID-19 cases. Hence, TNF-α blocking can possibly be a favorable intervention in modifying COVID-19. To this end, in order to manage pneumonia caused by COVID-19, adalimumab may potentially be considered as a potential therapeutic agent. The present study aimed to investigate the potential therapeutic role of adalimumab in treating COVID-19 cases in combination therapy with remdesivir and dexamethasone. METHODS: Among the 68 patients who were included in the current randomized controlled trial, 34 were assigned to the adalimumab group and the remaining 34 were assigned to the control group. Adalimumab at a dose of 40 mg, subcutaneous for once, was used for the intervention group. Both the intervention and control groups received remdesivir, dexamethasone, and supportive care. The data gathered to make comparisons of the groups included demographic information, the rate of mortality, mechanical ventilation requirement, length of stay in hospital and Intensive Care Unit (ICU), and imaging findings. RESULTS: There was no significant difference between the two groups in the terms of mortality rate (P-value = 1) and mechanical ventilation requirement (P-value = 1). The length of hospital and ICU stay as well as radiologic changes were not affected either (P-value = 1, 0.27, and 0.53, respectively). CONCLUSIONS: Our findings did not support the use of adalimumab in combination with remdesivir and dexamethasone in the treatment of severe COVID-19 cases.

Effect of COPD on Health-Related Quality of Life; Results from the BOLD Study in Iran.

BACKGROUND: Chronic obstructive pulmonary disease (COPD) has been the third leading cause of morbidity and the sixth leading cause of mortality in 2020. This chronic disease usually impairs health status and is an independent predictor of morbidity and mortality. The main objective of this study was to assess health-Related quality of life (HRQL) in a large sample of participants with and without COPD. MATERIALS AND METHODS: The present study was based on the data obtained from the population-based BOLD study in Iran. The sampling frame in this study included the whole population of 31 provinces of Iran. Participants were recruited using a stratified cluster sampling strategy with proportional allocations within strata. All the participants were requested to fill the Short Form 12 (SF-12) Health Survey Questionnaire, an abbreviated version of the SF-36. RESULTS: A total of 1062 subjects, including 479 (45%) males and 583 (54.7%) females, were enrolled in the study. The mean age of the participants was 40±15.04 years. The overall COPD prevalence based on the post-bronchodilator spirometry functional criteria was 5.0%. The mean PCS- 12 and MCS- 12 for all the subjects were 66.61±22.72 and 60.79±23.52, respectively. The mean scores of PCS and MCS were significantly lower in patients with COPD than those without COPD (P<0.001). CONCLUSION: The findings of this study demonstrated that COPD, female gender, and an age above 40 years influenced HRQL, especially the physical dimension, as shown by the SF-12 instrument.

Recommendations for Infantile-Onset and Late-Onset Pompe Disease: An Iranian Consensus.

Background: Pompe disease, also denoted as acid maltase or acid α-glucosidase deficiency or glycogen storage disease type II, is a rare, autosomal recessive lysosomal storage disorder. Several reports have previously described Pompe disease in Iran and considering increased awareness of related subspecialties and physicians, the disease's diagnosis is growing. Objective: This guideline's main objective was to develop a national guideline for Pompe disease based on national and international evidence adapting with national necessities. Methods: A group of expert clinicians with particular interests and experience in diagnosing and managing Pompe disease participated in developing this guideline. This group included adult neurologists, pediatric neurologists, pulmonologists, endocrinologists, cardiologists, pathologists, and physiatrists. After developing search terms, four authors performed an extensive literature review, including Embase, PubMed, and Google Scholar, from 1932 to current publications before the main meeting. Before the main consensus session, each panel member prepared an initial draft according to pertinent data in diagnosis and management and was presented in the panel discussion. Primary algorithms for the diagnosis and management of patients were prepared in the panel discussion. The prepared consensus was finalized after agreement and concordance between the panel members. Conclusion: Herein, we attempted to develop a consensus based on Iran's local requirements. The authors hope that disseminating these consensuses will help healthcare professionals in Iran achieve the diagnosis, suitable treatment, and better follow-up of patients with infantile-onset Pompe disease and late-onset Pompe disease.

Pulmonary Alveolar Proteinosis in Children: Diagnosis and Treatment Outcomes.

Background: Pulmonary Alveolar Proteinosis (PAP) is an uncommon pulmonary disease characterized by the accumulation of surfactant composed of proteins and lipids due to disruption of surfactant clearance by alveolar macrophages. The current standard treatment is lung lavage. There are no specific criteria for lavage, but in case of observing these signs it is recommended to perform lavage for the patient: progressive respiratory failure, no labored breathing at rest, and drop in oxygen level during activity (>5%). Materials and Methods: In this study, patients with PAP admitted to Pediatric ward of Masih Daneshvari Hospital were studied. The required data were collected including the patient's demographic data, clinical signs and radiographic data, the number of admissions, the age of diagnosis, detection and treatment methods, number of lavage, current condition of the patient, and in case of death, the cause of death. Results: In this study, 17 patients with PAP who were admitted during the past 15 years were examined; among which 7 patients were boys (41.2%) and 10 were girls (58.8%). The mean age of population was 11.79±7.21 years. Transbronchial Lung Biopsy (TBLB) (47.1%) and open lung biopsy (52.9%) were used for diagnosis of patients. Lung lavage was used to treat patients, 15 of whom were treated by this method. Five of the patients died because of their serious conditions. Conclusion: Therapy method in the present study was lavage for both lungs, and it was performed for all patients except for two patients due to their anatomical complications. This method is still considered as the gold standard for PAP. Considering the findings from previous studies and the present study, it seems that Whole Lung Lavage (WLL) was fruitful for patients who had the indication for using this therapy and it played a significant role in improving the prognosis of patients. Besides, it is recommended to do follow-up regularly in order to have more therapeutic efficacy and increased patient longevity.

High-Flow Nasal Oxygen Therapy in Acute Hypoxemic Respiratory Failure: Concise Review on Technology and Initial Methodology.

High-flow nasal cannula oxygen therapy (HFNCOT) system consists of an air/oxygen supply system capable of delivering up to 100% humidified and heated oxygen at a flow rate of up to 80 L/min. The system includes a blender, active humidifier, single heated tube, and nasal cannula. HFNCOT has many physiological advantages compared with other standard oxygen therapies, such as anatomical dead space washout, more constant fraction of inspired oxygen, positive end-expiratory (PEEP) effect, supplement of adequate humidification and maintenance of muco-ciliary function. HFNCOT is mostly used for hypoxemic acute respiratory failure, although it also has other indications. HFNCOT is a common choice of physicians as its technology makes it more silent and comfortable. Though HFNCOT is used in many clinical settings, there is a lack of publications addressing devices and initial settings. We present a review on HFNCOT, with focus on device and application methodology.

Favipiravir Effects on the Control of Clinical Symptoms of Hospitalized COVID-19 Cases: An Experience with Iranian Formulated Dosage Form.

Coronavirus disease -19 (COVID-19) pandemic, caused by SARS-CoV-2, has gradually spread worldwide, becoming a major public health event. This situation requires designing a novel antiviral agent against the SARS-CoV-2; however, this is time-consuming and the use of repurposed medicines may be promising. One such medicine is favipiravir, primarily introduced as an anti-influenza agent in east world. The aim of this study was to evaluate the efficacy and safety of favipiravir in comparison with lopinavir-ritonavir in SARS-CoV-2 infection. In this randomized clinical trial, 62 patients were recruited. These patients had bilateral pulmonary infiltration with peripheral oxygen saturation lower than 93%. The median time from symptoms onset to intervention initiation was seven days. Favipiravir was not available in the Iranian pharmaceutical market, and it was decided to formulate it at the research laboratory of School of Pharmacy, Shahid Beheshti University of Medical Sciences, Tehran, Iran. The patients received favipiravir tablet at a dose of 1600 mg orally twice a day for day one and then 600 mg orally twice a day for days 2 to 6. In the second group, the patients received lopinavir-ritonavir combination tablet at a dose of 200/50 mg twice a day for seven days. Fever, cough, and dyspnea were improved significantly in favipiravir group in comparison with lopinavir-ritonavir group on days four and five. Mortality rate and ICU stay in both groups were similar, and there was no significant difference in this regard (P = 0.463 and P = 0.286, respectively). Chest X-ray improvement also was not significantly different between the two groups. Adverse drug reactions occurred in both groups, and impaired liver enzymes were the most frequent adverse effect. In conclusion, early administration of oral favipiravir may reduce the duration of clinical signs and symptoms in patients with COVID-19 and hospitalization period. The mortality rate also should be investigated in future clinical trials.

Postural Balance Evaluation in Patients with Chronic Obstructive Pulmonary Disease.

BACKGROUND: The risk of falling in patients with chronic obstructive pulmonary disease (COPD) is higher than healthy people, imposing a great financial burden on patients due to clinical diagnosis and treatment. This study aimed to compare static balance between two groups of healthy people and COPD patients, based on cognitive tasks and vision tests, using linear and non-linear analyses. MATERIALS AND METHODS: A total of 15 patients with COPD and 14 age- and gender-matched healthy individuals were recruited in this study. Variations in the center of pressure were recorded in both medial-lateral (ML) and anterior-posterior (AP) directions by implementing visual feedback and cognitive tasks, with the subject standing on a force plate. Data related to the center of pressure were analyzed in the AP and ML directions by linear methods (i.e., standard deviation of displacement, standard deviation of maximum velocity, average velocity, and phase plane). Also, the nonlinear method (Lyapunov exponents) was used in both directions. RESULTS: The cognitive tasks improved the center of pressure variables in both groups. In association with the vision tests, only lack of vision had a significant effect on the patients. The results of the linear analysis in the ML direction were significantly higher in the COPD group as compared to the healthy group; however, the results were not significant in the AP direction. Also, the non-linear analysis showed significant differences between the groups. CONCLUSION: Use of both linear and non-linear analyses is necessary for evaluating the balance of patients with breathing difficulties. Balance disorders in COPD patients were mostly in the ML direction; therefore, postural deformities might be one of the reasons for balance problems in the AP direction.

The Optimal Cut-off Score of the Nijmegen Questionnaire for Diagnosing Hyperventilation Syndrome Using a Bayesian Model in the Absence of a Gold Standard.

BACKGROUND: The Nijmegen questionnaire is one of the most common tools for diagnosing hyperventilation syndrome (HVS). However, there is no precise cut-off score for differentiating patients with HVS from those without HVS. This study was conducted to evaluate the accuracy of Nijmegen questionnaire for detecting patients with HVS and to provide the best cut-off score for differentiating patients with HVS from normal individuals using a Bayesian model in the absence of a gold standard. MATERIALS AND METHODS: A total of 490 students from a rehabilitation center in Tehran, Iran, were asked to participate in this case study of HVS from January to August 2018. RESULTS: A total of 215 students (40% male and 60% female) completed the Nijmegen questionnaire. The area under the receiver operating characteristic curve (AUC) was 0.93 (male: 0.95; female: 94) for all of the cut-off scores. The optimal cut-off score of ≥20 could predict HVS with sensitivity of 0.91 (male: 0.99; female: 91) and specificity of 0.92 (male: 96; female: 89). CONCLUSION: Accurate differentiation of HVS patients from individuals without HVS can be accomplished by estimating the cut-off score of Nijmegen questionnaire based on a non-parametric Bayesian model.