A Retrospective Review of 18 Patients With Childhood-Onset Hereditary Spastic Paraplegia, Nine With Novel Variants.

BACKGROUND: Hereditary spastic paraplegias (HSPs) are a group of genetically heterogeneous neurodegenerative disorders. Our objective was to determine the clinical and molecular characteristics of patients with genetically confirmed childhood-onset HSPs and to expand the genetic spectrum for some rare subtypes of HSP. METHODS: We reviewed the charts of subjects with genetically confirmed childhood-onset HSP. The age at the disease onset was defined as the point at which the delayed motor milestones were observed. Delayed motor milestones were defined as being unable to hold the head up by four months, sitting unassisted by nine months, and walking independently by 17 months. If there were no delayed motor milestones, age at disease onset was determined by leg stiffness, frequent falls, or unsteady gait. Genetic testing was performed based on delayed motor milestones, progressive leg spasticity, and gait difficulty. The variant classification was determined based on the American College of Medical Genetics standard guidelines for variant interpretation. Variants of uncertain significance (VUS) were considered disease-associated when clinical findings were consistent with the previously described disease phenotypes for pathogenic variants. In addition, in the absence of another pathogenic, likely pathogenic, or VUS variant that could explain the phenotype of our cases, we concluded that the disease is associated with VUS in the HSP-causing gene. Segregation analysis was also performed on the parents of some patients to demonstrate the inheritance model. RESULTS: There were a total of 18 patients from 17 families. The median age of symptom onset was 18 months (2 to 84 months). The mean delay between symptom onset and genetic diagnosis was 5.8 years (5 months to 17 years). All patients had gait difficulty caused by progressive leg spasticity and weakness. Independent walking was not achieved at 17 months for 67% of patients (n = 12). In our cohort, there were two subjects each with SPG11, SPG46, and SPG 50 followed by single subject each with SPG3A, SPG4, SPG7, SPG8, SPG30, SPG35, SPG43, SPG44, SPG57, SPG62, infantile-onset ascending spastic paralysis (IAHSP), and spastic paraplegia and psychomotor retardation with or without seizures (SPPRS). Eight novel variants in nine patients were described. Two affected siblings had a novel variant in the GBA2 gene (SPG46), and one subject each had a novel variant in WASHC5 (SPG8), SPG11 (SPG11), KIF1A (SPG30), GJC2 (SPG44), ERLIN1 (SPG62), ALS2 (IAHSP), and HACE1 (SPPRS). Among the novel variants, the variant in the SPG11 was pathogenic and the variants in the KIF1A, GJC2, and HACE1 were likely pathogenic. The variants in the GBA2, ALS2, ERLIN1, and WASHC5 were classified as VUS. CONCLUSIONS: There was a significant delay between symptom onset and genetic diagnosis of HSP. An early diagnosis may be possible by examining patients with delayed motor milestones, progressive spasticity, gait difficulties, and neuromuscular weakness in the context of HSP. Eight novel variants in nine patients were described, clinically similar to the previously described disease phenotype associated with pathogenic variants. This study contributes to expanding the genetic spectrum of some rare subtypes of HSP.

Association of epilepsy with neuroimaging patterns in children with cerebral palsy.

OBJECTIVES: In this study, we examined whether epilepsy and drug-resistant epilepsy are associated with neuroimaging findings in children with cerebral palsy (CP). METHODS: Magnetic resonance imaging classification system (MRICS) proposed by Surveillance of Cerebral Palsy in Europe (SCPE) was used for classification of different MRI patterns in patients with cerebral palsy. We reviewed the brain MRI scans and medical records of children with CP who were followed-up in our clinic between 2019 and 2023. Patients were divided into three categories: CP without epilepsy, CP with controlled epilepsy and CP with DRE. MRI patterns were grouped as maldevelopments, predominant white matter injury, predominant gray matter injury, miscellaneous (delayed myelination, cerebral atrophy, cerebellar atrophy, brainstem lesions and calcifications, lesions that were not classified under any other group) and normal according to MRICS of the SCPE. RESULTS: There were 325 CP patients. The most common MRI patterns were predominant white matter injury (47.6%) and gray matter injury (23.8%). There was a 1.5-fold reduction in the risk of epilepsy in patients with predominant white matter injury (OR = 1.54, 95% CI 1.23-1.94). In contrast, children in the miscellaneous group had significantly higher risks of epilepsy (p < 0.001), and we were able to determine that miscellaneous findings increased the risk by 1.8 times (OR = 1.77, 95% CI 1.47-2.12). CONCLUSION: In conclusion, more than half of the children with CP had epilepsy, 40.7% of whom had DRE. On MRI, miscellaneous findings may indicate a poor prognosis for epilepsy, while predominant white matter injury may indicate a good outcome. Children with CP, especially those with miscellaneous findings on MRI, should be closely monitored for epilepsy development.

Effects of Personal Protective Equipment on Speech Acoustics.

Objectives: The transmission of severe acute respiratory syndrome coronavirus-2 occurs primarily through droplets, which highlights the importance of protecting the oral, nasal, and conjunctival mucosas using personal protective equipment (PPE). The use of PPE can lead to communication difficulties between healthcare workers and patients. This study aimed to investigate changes in the acoustic parameters of speech sounds when different types of PPE are used. Methods: A cross-sectional study was conducted, enrolling 18 healthy male and female participants. They were instructed to produce a sustained [ɑː] vowel for at least 3 s to estimate voice quality. In addition, all Turkish vowels were produced for a minimum of 200 ms. Finally, three Turkish fricative consonants ([f], [s], and [ʃ]) were produced in a consonant/vowel/consonant format with different vowel contexts within a carrier sentence. Recordings were repeated under the following conditions: no PPE, surgical mask, N99 mask, face shield, surgical mask + face shield, and N99 mask + face shield. All recordings were subjected to analysis. Results: Frequency perturbation parameters did not show significant differences. However, in males, all vowels except [u] in the first formant (F1), except [ɔ] and [u] in the second formant (F2), except [ɛ] and [ɔ] in the third formant (F3), and only [i] in the fourth formant (F4) were significant. In females, all vowels except [i] in F1, except [u] in F2, all vowels in F3, and except [u] and [ɯ] in F4 were significant. Spectral moment values exhibited significance in both groups. Conclusion: The use of different types of PPE resulted in variations in speech acoustic features. These findings may be attributed to the filtering effects of PPE on specific frequencies and the potential chamber effect in front of the face. Understanding the impact of PPE on speech acoustics contributes to addressing communication challenges in healthcare settings.

Genetic and clinical evaluation of congenital myasthenic syndromes with long-term follow-up: experience of a tertiary center in Turkey.

INTRODUCTION: Congenital myasthenic syndromes (CMS) are a heterogeneous group of genetic disorders affecting the safety factor which required for neuromuscular transmission. Here we reported our experience in children with CMS. METHODS: We retrospectively collected the data of 18 patients with CMS who were examined in our outpatient clinic between January 2021 and January 2022. The diagnosis of CMS was based on the presence of clinical symptoms such as abnormal fatigability and weakness, absence of autoantibodies against acetylcholine receptor and muscle-specific kinase, electromyographic evidence of neuromuscular junction defect, molecular genetic confirmation, and response to treatment. RESULTS: The most common mutations were in the acetylcholine receptor (CHRNE) gene (8/18) and choline acetyltransferase (ChAT) (2/18) gene. Despite targeted gene sequencing and whole exome sequencing (WES) were underwent, we couldn't detect a genetic mutation in three out of patients. The most commonly determined initial finding was eyelid ptosis, followed by fatigable weakness, and respiratory insufficiency. Although the most commonly used drug was pyridostigmine, we have experienced that caution should be exercised as it may worsen some types of CMS. DISCUSSION: We reported in detail the phenotypic features of very rare gene mutations associated with CMS and our experience in the treatment of this disease. Although CMS are rare genetic disorder, the prognosis can be very promising with appropriate treatment in most CMS subtypes.

Pulsed-wave Doppler ultrasonographical measurements of supra-mammary lymph nodes for diagnosis of bovine mastitis.

The aim of this study was to investigate the relationship between mastitis and supra-mammary lymph nodes in lactating cows in terms of Pulsed-wave (PW) Doppler ultrasonographical measurements. A total of 102 head cows in lactation period were divided into three groups. The cows in which all mammary lobes were California mastitis test (CMT)-negative (n = 27) formed the 1st group; those with CMT-positive mammary lobe (n = 43) formed the 2nd group and the cows with clinical mastitis in at least one mammary lobe (n = 32) formed the 3rd group. In PW Doppler ultrasonography, end-diastolic velocity, systolic peak velocity and time-averaged maximum velocity were measured at the most prominent artery of the lymph node. A quantitative scaling was performed by determining the pulsatile index and resistance index scales based on blood flow parameters. There was no statistically significant difference between the study groups in terms of PW Doppler ultrasonographical measurements of supra-mammary lymph nodes. In conclusion, the use of PW Doppler ultrasonographic data of the supra-mammary lymph nodes will not provide useful information about the current condition of mastitis in cows.

Homozygous SQSTM1 nonsense variant identified in a patient with brainstem involvement.

In recent years, with advances in molecular genetics, many new mutations with various ataxic syndromes have been identified. Recently, homozygous sequestosome 1 (SQSTM1) gene variant with a progressive childhood-onset cerebellar ataxia, dystonia and gaze palsy was described. Here we describe a patient with progressive cerebellar ataxia and gaze palsy, as well as myoclonus, cognitive impairment and growth retardation with a homozygous SQSTM1 variant NM_003900.5:c.55G > T (p.Glu19*). Our case had brainstem lesions on brain magnetic resonance imaging that have not been previously reported. This novel finding expands the SQSTM1 gene-associated neuroradiologic spectrum. Homozygous SQSTM1 variant should be considered in the differential diagnosis in patients presenting with cerebellar findings, gaze palsy, and cognitive impairment to facilitate early diagnosis and genetic counseling.

Glucose 6 phosphate dehydrogenase deficiency: A single-center experience.

OBJECTIVE: This study aims to evaluate the demographic information, clinical and laboratory findings of patients with glucose 6 phosphate dehydrogenase deficiency. MATERIAL AND METHODS: We collected data by reviewing files and electronic records of 65 patients with glucose 6 phosphate dehydrogenase deficiency under the age of 18 years who were followed up in our clinic between 2007 and 2019. Demographic, clinical, and laboratory features, family history, complications of the disease, and history of splenectomy and cholecystectomy were evaluated. Mean, standard deviation, and median values were used when descriptive analyses were presented. RESULTS: The age of diagnosis ranged between 1-192 months and the median age of diagnosis was two months. Fifty-nine patients (90.7%) were boys and six (9.2%) were girls. The mean value of glucose 6 phosphate dehydrogenase enzyme on admission was 1,9±1,4 U/g of hemoglobin (Hb). Family history was pesent in 40% of patients in whom information was avaliable. The most common presentation was prolonged jaundice and the most common physical finding was jaundice. Splenomegaly was detected in none of the patients. Cholelithiasis was present in one of 21 patients who were evaluated with ultrasonography. None of the patients required splenectomy, cholecystectomy, and regular erythrocyte transfusion during follow-up. CONCLUSION: As G6PD variants with chronic hemolysis are not usually seen in Turkey, patients who required splenectomy, cholecystectomy, and regular erythrocyte transfusion were not detected. Although glucose 6 phosphate dehydrogenase deficiency is more common in males, it can also be seen in girls. In Turkey, glucose 6 phosphate dehydrogenase deficiency should be considered in patients presenting with prolonged jaundice.

Evaluation of eating behaviors in childhood epilepsy with centrotemporal spikes: Case-control study.

BACKGROUND: Psychosocial and behavioral disorders have been reported in childhood epilepsy with centrotemporal spikes (CECTS). We aimed to identify the symptoms of eating disorders in CECTS. METHODS: Patients with CECTS were recruited from the pediatric neurology outpatient clinic between September 2019 and July 2020. The Children's Eating Behaviour Questionnaire (CEBQ) was administered to 39 patients and 31 controls. Patients' scores were compared with those of healthy subjects. RESULTS: There was no significant difference between the CEBQ of patients with CECTS and the control group (p > 0.05). There was no significant difference between the BMI of the patients with CECTS and the control group. In the patient group with CECTS, no significant difference was found in terms of CEBQ according to the antiepileptic drug used and EEG findings (p > 0.05). CONCLUSION: No difference was found in the eating habits of patients with CECTS compared with the healthy control group.

G protein coupled oestrogen receptor 1, aromatase, 17ß-HSD and cAMP level in mutational falsetto.

OBJECTIVES: Puberphonia or mutational falsetto (MF) is seen more in males, and hormonal changes are considered to be among the aetiological causes. Therefore, the aim of this study was to investigate the molecules [G protein-coupled oestrogen receptor 1 (GPER-1), aromatase, 17-beta-hydroxysteroid dehydrogenase (17ß-HSD), cyclic adenosine monophosphate (cAMP) levels] related to receptors and pathways in patients with MF. METHODS: The study included 30 MF patients and a control group of 30 healthy individuals. Voice recordings were made of the MF patients and acoustic analyses were applied. The serum GPER-1, aromatase, 17ß-HSD, cAMP levels and TSH, estradiol, prolactin, progesterone, and testosterone levels were evaluated in venous blood samples. RESULTS: In the MF patients, the GPER-1 level determined of mean 3.68 (1.95-4.26) pg/ml, 17 beta dehydrogenase of 5.25 (2.73-6.77) ng/ml, and cAMP of 24.62 (11.62-30.35) ng/ml were statistically signficantly higher than those of the control group (p = 0.008, p = 0.002, p = 0.003, respectively). The aromatase level in the MF patients was found to be 3.48 (2.01-4.91) and the difference between the two groups was not statistically significant (p = 0.067). CONCLUSION: The GPER-1, 17ß-HSD, and cAMP levels were found to be higher in the MF patients than in the control group, suggesting that they could be of importance in the diagnosis and treatment of MF.

Voice Acoustic Analysis of Pediatric Vocal Nodule Patients Using Ratios Calculated With Biomedical Image Segmentation.

OBJECTIVE: The aim of this study was to determine nodules using newly developed software with a computer-assisted visual process technique for the calculation of size. The effects of the ratios of nodule base and width were evaluated with voice acoustic analysis. METHODS: A total of 72 patients with pediatric vocal nodule were evaluated. Nodules were marked with the ImageJ News program on photographs obtained from the video recordings in the videostroboscopic examination and classified according to the Shah et al scale. Segmentation was applied automatically. The ratios were taken as base of nodule/width and base of nodule/vocal cord. In the voice acoustic analysis, basic frequencies (mean F0), jitter (local %), shimmer (local %), and harmonicity (mean harmonics-to-noise [mean HNR]) were evaluated. RESULTS: A statistically significant negative correlation was determined between the mean F0 value and the nodule base/width ratio (P = 0.042, r = -0.240). A negative statistically significant relationship was determined between jitter (%) and vocal nodule base/width (P = 0.009, r = -0.305). A statistically significant positive correlation was determined between mean HNR and vocal nodule base/width (P = 0.034, r = 0.324). In discriminant analysis, correct classification of the Shah et al scale degrees of the classifying variables was 73.6%. CONCLUSION: Through collaboration with the biomedical engineering department, the results of this study determined new ratios in patients with pediatric vocal nodule. In voice acoustic analysis, the mean F0 was more affected by the width of the nodule, mean HNR was affected by the length of the base of the nodule, and jitter (%) was affected by the width of the nodule.

Transfer of ochratoxin A from raw black tea to tea infusions prepared according to the Turkish tradition.

BACKGROUND: Ochratoxin A (OTA) is a natural contaminant of food including tea with multiple toxic effects, which poses a threat to human health. In terms of lifestyle, the Turkish population is a frequent visitor of tearooms, and the traditional Turkish tea preparation is one of the most popular ways of preparing tea infusion. RESULTS: The aim of this study was to investigate OTA transfer from raw black tea to the tea infusion prepared according to the Turkish tradition. A high-performance liquid chromatography method with a limit of quantification of 0.35 ng g-1 was used for OTA determination. The OTA amount in raw black teas from Turkey ranged from ≤0.35 ng g-1 up to 56.7 ng g-1 . An homogenised sample of black tea naturally contaminated with 55.0 ng g-1 was used to prepare infusions. The OTA transfer from the black tea to the infusion was found to be 41.5% ± 7%. CONCLUSION: These data are important for the realisation of a 'Total Diet study' (TDS). The TDS can be a complementary tool to estimate the population dietary exposure to OTA across the entire diet by analysing main foods prepared 'as consumed' (tea infusions) and not 'as purchased' (raw tea). © 2017 Society of Chemical Industry.

An evaluation of oxidative and nitrosative stress in children-who-stutter and its relationship to severity.

OBJECTIVES: Although there has been much research into the cause of stuttering, it has not yet been fully clarified. There is known to be a close relationship between stress severity and stuttering. The aim of this study was to evaluate the levels of oxidative and nitrosative stress by comparing a stuttering group and a control group. It was also aimed to evaluate the relationship between the oxidative and nitrosative stress levels and the severity of the stutter. METHODS: The study included a total of 80 individuals, comprising a study group of 40 and a control group of 40. The severity of the stutter in the patient group was evaluated with the Stuttering Severity Instrument 3 (SSI). Blood samples were taken from both the patient and control groups and malondialdehyde (MDA), 3 nitrotyrosine (3-NT), nitric oxide (NO), catalase (CAT), and superoxide dismutase (SOD) concentrations were examined. RESULTS: In the stuttering patients, MDA, 3-NT, NO, CAT, and SOD activity were determined to be statistically significantly higher than those of the control group (all p:0.001). In the ROC analysis, there was good diagnostic value for NO, with the area under the curve as 1.0. A direct, positive, statistically significant correlation was determined between SSI points and MDA values (r = 0.317, p = 0.046). CONCLUSION: The results of the study showed that the oxidative and nitrosative stress levels of the stuttering patients were higher than those of the control group. With 100% sensitivity and specificity, it is thought that NO in particular could be important for the diagnosis and treatment of these patients. As the severity of the stutter increased, so there was an increase in MDA, suggesting that MDA is important in stuttering.

Diabetogenic Effects of Ochratoxin A in Female Rats.

In this study, the diabetogenic effects of long term Ochratoxin A (OTA) administration in rats were investigated, and its role in the etiology of diabetes mellitus (DM) was examined utilizing 42 female Wistar rats for these purposes. The rats were divided into three different study and control groups according to the duration of the OTA administration. The rats received 45 µg OTA daily in their feed for 6, 9 and 24 weeks, respectively. Three control groups were also used for the same time periods. Blood and pancreatic tissue samples were collected during the necropsy at the end of the 6, 9 and 24 weeks. The plasma values of insulin, glucagon and glucose were determined for the study and control groups. Pancreatic lesions were evaluated via histopathological examination and insulin and glucagon expression in these lesions was subsequently determined using immunohistochemical methods. Statistically significant decreases in insulin levels were observed, in contrast to increases in blood glucagon and glucose levels. Histopathological examinations revealed slight to moderate degeneration in Langerhans islet cells in all OTA-treated groups. Immunohistochemistry of pancreatic tissue revealed decreased insulin and increased glucagon expression. This study demonstrated that OTA may cause pancreatic damage in the Langerhans islet and predispose rats to DM.

[Validation and reliability of Turkish Singing Voice Handicap index]. / Özgün San Sesi Handikap Endeksi ölçeginin Türkçe versiyonunun geçerlik ve güvenirligi.

OBJECTIVES: This study aims to constitute a valid and reliable Turkish version of the original Singing Voice Handicap Index. PATIENTS AND METHODS: An authorized committee assessed the reliability and validity of the content, scope, and language of the original Singing Voice Handicap Index which underwent a back translation process. The Turkish version of the questionnaire was answered twice with a 7 to 10-day interval by two singing voice groups with or without singing voice problems. The reliability and validity analyses were performed based on these answers. RESULTS: Of a total of 123 individuals (64 females, 59 males; mean age 26.2±7.3 years), 81 were without a voice pathology and 42 were with a voice pathology. The total Cronbach's alpha coefficient was 0.917. The item-total correlations ranged between 0.51 and 0.89. The weighted kappa values of test-retest correlation values of the items were 0.82-0.91. The Cronbach's alpha values of two part of the questionnaire based on the split-half method were 0.89 and 0.84. The mean total scale scores were 21.8±18.5 and 53.6±28.9 in normal and pathology groups, respectively and there was a statistically significant difference in scores between these two groups (p=0.000). CONCLUSION: The Turkish version of the Singing Voice Handicap Index is a valid and reliable scale which can be used in the evaluation of voice problems of Turkish-speaking singing voice users.

Influence of the macroscopic features of vocal fold polyps on the quality of voice: a retrospective review of 101 cases.

We conducted a study to examine six macroscopic features of vocal fold polyps and to investigate their influence on quality of voice. We retrospectively reviewed the records of 101 consecutive patients with vocal fold polyps who had undergone microlaryngeal surgery for polyp removal after conservative measures had failed. All patients had undergone videolaryngostroboscopy and perceptual and acoustic voice analyses. The six macroscopic features of these vocal fold polyps were morphologic type, location, position, shape, size, and the presence or absence of a reactive lesion on the contralateral vocal fold. Among our statistically significant findings were that gelatinous polyps tended to be broad-based; polyps located on the superior surface tended to be hemorrhagic; small polyps were mostly located on the middle one-third of the vocal fold, and most of them were broad-based; and all of the polyps that were accompanied by reactive lesions on the contralateral vocal fold were located on the free edge. Moreover, jitter was found to be low in small polyps. Finally, noise-to-harmonics ratios were significantly higher in patients with anterior polyps and in those with pedunculated polyps. We conclude that each of the six macroscopic features of vocal fold polyps affected vocal function to a certain degree. We believe that our study provides additional information to otolaryngologists and speech language pathologists who deal with vocal fold polyps.

The effects of surgical rapid maxillary expansion (SRME) on vowel formants.

The objective of this study was to investigate the effect of surgical rapid maxillary expansion (SRME) on vowel production. The subjects included 12 patients, whose speech were considered perceptually normal, that had undergone surgical RME for expansion of a narrow maxilla. They uttered the following Turkish vowels, ([a], [e], [dotless i], [i], [o], [oe], [u], [y]), in isolation before and after the maxillary expansion. These samples were recorded for acoustical analysis. The fundamental frequencies (F0) and the frequencies and bandwidths of the first two formants (F1 and F2) of the vowels were measured using the Multi-Speech programme (Kay Elemetrics). Statistical analysis revealed that the second formant frequency (F2) and bandwidth values in the vowel [i] and [oe] were lowered after maxillary expansion (p<.05). Surgical RME induced the decrease in the second formant of the [i] and [oe] vowels by affecting the size of the anterior oral cavity, however the influence was too small to cause any differences in the acoustic properties of the other vowels.

[Reliability and validity of the Turkish version of the Voice Handicap Index]. / Ses Handikap Endeksi (Voice Handicap Index) Türkçe versiyonunun güvenilirligi ve geçerliligi.

OBJECTIVES: We investigated the reliability and validity of the Turkish version of the Voice Handicap Index (VHI), and developed a short VHI form that would be more practical. PATIENTS AND METHODS: The original VHI was translated to Turkish by 10 otolaryngologists, then it was translated back to English by a linguist, and the final text was prepared by the evaluation committee composed of three members. The translated version was administered to a group of 220 subjects twice with 7-14 days intervals. Based on the responses, statistical analyses were performed to assess its reliability and validity. RESULTS: Internal consistency reliability was found to be highly significant (Cronbach's alpha=0.97). Test-retest correlation coefficient was 0.93 for the total score. Factor analysis yielded three factors explaining 64.8% of the total variance. The corrected item-total correlation coefficients ranged from 0.50 to 0.80. The 10 most robust VHI items, namely, E7, E9, P10, F11, F12, E15, F16, P18, P20 and E29, were selected using the corrected item-total correlation coefficients, and a shortened form of the Turkish VHI was developed. CONCLUSION: As some items are thought to be contentious in the Turkish VHI, the short form of the Turkish VHI is more suitable for use in clinics.

The effect of stimulus duration on perception of Turkish vowels in normal-hearing and hearing-impaired children.

The objective of the study was to examine the effects of stimulus duration on vowel perception in normal-hearing and hearing-impaired children. For this purpose, 80 semisynthetic vowel stimuli consisting of eight different Turkish vowels with ten different durations were presented to 14 normal-hearing and 15 hearing impaired children, and they were asked to identify the vowel they heard. Thirteen normal-hearing adults served as speaker subjects to get normative data on mean durations of the Turkish vowels. While there was no significant effect of duration on perception in normal-hearing children, perception errors for very short and very long vowels were observed in hearing-impaired children. The most frequent responses as a function of duration showed four different patterns: (1) three vowels were perceived correctly in all durations; (2) two were perceived correctly in middle and longer durations; (3) two were perceived correctly in middle duration; and (4) only one was perceived correctly in short duration. It was concluded that the effects of stimulus duration on vowel perception were determined by natural duration of the vowel in a given language, and unnaturally short and long vowels were misperceived by hearing impaired subjects.

The effects of vowels on voice perturbation measures.

This study examines voice perturbation parameters of the sustained [a] in English and of the eight vowels in Turkish to discover whether any difference exists between these languages, and whether a correlation exists between voice perturbation parameters and articulatory and acoustic properties of the Turkish vowels. Eight Turkish vowels uttered by 26 healthy nonsmoker volunteer males who are native Turkish speakers were compared with a voice database that includes samples of normal and disordered voices belonging to American English speakers. Fundamental frequencies, the first and second formants, and perturbation parameters, such as jitter percent, pitch perturbation quotient, shimmer percent, and amplitude perturbation quotient of the sustained vowels, were measured. Also, the first and second formants of the sustained [a] in English were measured, and other parameters have been obtained from the database. When the voice perturbation parameters in Turkish and English were compared, statistically significant differences were not found. However, when Turkish vowels compared with each other, statistically significant differences were found among perturbation values. Categorical comparisons of the Turkish vowels like high-low, rounded-unrounded, and front-back revealed significant differences in perturbation values. In correlation analysis, a weak linear inverse relation between jitter percent and the first formant (r=-0.260, p<0.05) was found.