Biomedical subjects

Katrin Neumann

Publications and source records attributed to Katrin Neumann.

11 recordsLinked to original sources

PubMed2006

Auditory status of persons with intellectual disability at the German Special Olympic Games.

Among persons with intellectual disability, the prevalence of hearing impairments is high. During the German Special Olympics Summer Games 2004, a hearing screening was conducted on 755 athletes with intellectual disabilities. Obligatory screening included ear inspection and recording of otoacoustic emissions, and optional screening included tympanometry and brief pure-tone audiometry. 38.0% of the athletes failed the screening. 53.0% needed ear wax removal. 56.1% of the fails indicated sensorineural hearing loss and 13.6% indicated mixed hearing loss. 12.5% of the fails were caused by unremovable ear wax, 1.4% by ear canal affections, and 16.4% by middle ear problems. Left ear fails were more frequent than right ear fails. A peripheral hearing disturbance can thus be expected in every third subject. The high failure rate, a considerable percentage of previously undetected profound hearing loss (1.1%), and the frequent need for ear wax removal, suggest that nearly half of persons with intellectual disabilities need regular otological or audiological consultations.

Acoustic Impedance Tests↗

PubMed2006

Effectiveness and efficiency of a universal newborn hearing screening in Germany.

The decision to mandate, finance, and implement a universal newborn hearing screening (UNHS) requires the evaluation of its therapy-directed benefit by comparing (1) a procedure employing a UNHS with (2) a targeted screening for at-risk babies for neonatal hearing disorders and (3) a procedure without systematic screening. In a cohort study the outcome of the UNHS program of Hessen in 2005 with 17,439 screened newborns was analyzed. Validity, effectiveness, and efficiency were evaluated and compared to a sample of 98 Hessian and 355 German children who were detected in 2005 as hearing-impaired but not by an UNHS. The UNHS group had a PASS rate of 97.0%. Forty-nine hearing-impaired children were diagnosed at a median age of 3.1 months and treated at a median age of 3.5 months. Corresponding values for the Hessian non-UNHS group were 17.8 and 21.0 months. For Germany the median age at diagnosis was 39.0 months. The age at therapy onset correlated negatively with parameters of speech/language and psychosocial development. A targeted screening would have resulted in a low sensitivity of 65.3%. Hence, a UNHS is the most effective way to an early therapy of neonatal hearing disorders with an optimal outcome.

Adolescent↗

PubMed2005

Cortical plasticity associated with stuttering therapy.

UNLABELLED: Neuroimaging studies have indicated that persistent developmental stuttering (PDS) may be associated both with an abnormality in white matter of left-hemispheric speech areas and a right-hemispheric hyperactivity. The latter may compensate for the deficient structural connectivity in the left hemisphere. To investigate the effects of stuttering therapy on brain activity nine male adults with PDS underwent functional magnetic resonance imaging (fMRI) before and within 12 weeks after fluency shaping therapy. Brain response differences during overt sentence reading before and after therapy were assessed by utilizing random effects analyses. After therapy, a more widespread activation was observed in frontal speech and language regions and temporal areas of both hemispheres, particularly and more pronounced on the left side. Interestingly, distinct posttreatment left-sided activation increases were located directly adjacent to a recently detected area of white matter anomaly [M. Sommer, M.A. Koch, W. Paulus, C. Weiller, C. Buchel (2002). Disconnection of speech-relevant brain areas in persistent developmental stuttering. The Lancet, 360, 380-383] suggesting that fluency shaping techniques reorganize neuronal communication between left-sided speech motor planning, motor execution, and temporal areas. Hence, a therapeutic mechanism can be assumed to remodel brain circuitry close to the source of the dysfunction instead of reinforcing compensation via homologous contralateral brain networks. EDUCATIONAL OBJECTIVES: The reader will learn about and be able to: (1) describe brain activation changes detected shortly after fluency-shaping therapy; (2) identify left-hemispheric regions where a (re)functionalization after fluency-shaping therapy seems to occur adjacent to a recently described abnormal white matter region in PDS subjects; and (3) discuss how an effective cerebral compensation mechanism for stuttering could work.

Adult↗

PubMed2005

Production of cyanophycin, a suitable source for the biodegradable polymer polyaspartate, in transgenic plants.

The production of biodegradable polymers in transgenic plants in order to replace petrochemical compounds is an important challenge for plant biotechnology. Polyaspartate, a biodegradable substitute for polycarboxylates, is the backbone of the cyanobacterial storage material cyanophycin. Cyanophycin, a copolymer of l-aspartic acid and l-arginine, is produced via non-ribosomal polypeptide biosynthesis by the enzyme cyanophycin synthetase. A gene from Thermosynechococcus elongatus BP-1 encoding cyanophycin synthetase has been expressed constitutively in tobacco and potato. The presence of the transgene-encoded messenger RNA (mRNA) correlated with changes in leaf morphology and decelerated growth. Such transgenic plants were found to produce up to 1.1% dry weight of a polymer with cyanophycin-like properties. Aggregated material, able to bind a specific cyanophycin antibody, was detected in the cytoplasm and the nucleus of the transgenic plants.

Journal Article↗

PubMed2003

Alport syndrome with diffuse leiomyomatosis.

Alport syndrome (AS) is a hereditary nephropathy with hematuria progressing to end-stage renal failure (ESRF), sensorineural deafness, and specific eye signs (lenticonus, macular flecks, and congenital cataracts). Inheritance is X-linked in about 85% of the cases, caused by different mutations in the COL4A5 gene. Rarely AS is seen in combination with diffuse leiomyomatosis (DL). DL is a tumorous process involving smooth muscle cells, mostly of the esophagus, but also of the tracheobronchial tree and the female genital tract. Characteristically, the patients have deletions of the 5'-end of both the COL4A5 and the COL4A6 genes, respectively. We here present a 9-year-old boy who was admitted because of a newly diagnosed sensorineural deafness. He was born with cataracts and presented symptoms of dysphagia and bronchial irritation in the first year of life. Macroscopic hematuria was first noticed at 2 years during a febrile infection. Since early childhood the boy suffered from severe constipation. Taking together these symptoms, the diagnosis of Alport syndrome with diffuse leiomyomatosis (AS-DL) has to be considered. Genetic analysis demonstrated the predicted deletion of the COL4A5/COL4A6 genes.

Child↗

PubMed2003

The nature and treatment of stuttering as revealed by fMRI A within- and between-group comparison.

UNLABELLED: This article reviews some of our recent functional magnetic resonance imaging (fMRI) studies of stuttering. Using event-related fMRI experiments, we investigated brain activation during speech production. Results of three studies comparing persons who stutter (PWS) and persons who do not stutter (PWNS) are outlined. Their findings point to a region in the right frontal operculum (RFO) that was consistently implicated in stuttering. During overt reading and before fluency shaping therapy, PWS showed higher and more distributed neuronal activation than PWNS. Immediately after therapy differential activations were even more distributed and left sided. They extended to frontal, temporal, and parietal regions, anterior cingulate, insula, and putamen. These over-activations were slightly reduced and again more right sided two years after therapy. Left frontal deactivations remained stable over two years of observation, and therefore possibly indicate a dysfunction. After therapy, we noted higher activations in persons who stutter moderately than in those who stutter severely. These activations might reflect patterns of compensation. We discuss why these findings suggest that fluency-inducing techniques might synchronize a disturbed signal transmission between auditory, speech motor planning, and motor areas. EDUCATIONAL OBJECTIVES: The reader will learn about and be able to: (1) identify regions of brain activations and deactivations specific for PWS; (2) describe brain activation changes induced by fluency shaping therapy; and (3) discuss the correlation between stuttering severity and brain activation.

Adult↗

PubMed2003

A new method to record subglottal pressure waves: potential applications.

Rapid subglottal pressure changes related to the glottal cycles influence the aerodynamics of phonation. Various methods to measure these have been developed, but are not practical for routine phoniatric use. For that reason, a noninvasive measurement tool is necessary. This article presents a technique that uses a microphone positioned at the skin of the jugular fossa to record the signal which arises in the subglottal spaces and is transmitted through the soft tissue to the surface of the skin. Using the program Glottal Segmentation of Voice and Speech, jugular microphone recordings from two healthy subjects were compared with simultaneously recorded direct intratracheal measurements during the same phonation. A systematic error arising from the transmission properties of the microphone and the soft tissue leads to phase and amplitude deviations. These must be taken into account and require correction. This correction procedure leads to high correlations and a good agreement between the two signals. Even without this correction the jugular microphone measurements proved to be useful as a diagnostic and a therapeutic tool in cases where chest resonance specific processes appear affected. In addition, they offer material for research purposes. Although based on a small number of subjects, the new method shows a good validity; testing on a larger number of subjects will probably strengthen the validity.

Adult↗

PubMed2003

Event-related fMRI for the suppression of speech-associated artifacts in stuttering.

The purpose of this study was to establish functional magnetic resonance imaging (fMRI) for the investigation of brain function during overt speech production in stuttering. Up to now this technique has rarely been used for the investigation of speech production paradigms because artifacts related to overt speaking largely impair the sensitivity toward task-related activation. Recently, the temporal delay of the hemodynamic response has been exploited to achieve a suppression of speech-related artifacts. By the limitation to very short utterances (one word), a temporal segregation of the respective effects was accomplished by means of an event-related experimental design. However, the investigation of speech production in persons who stutter requires a more extensive speaking situation. Since longer and more complex utterances evoke more symptoms of stuttering than reading of single words, a useful task should at least include the reading of full sentences. In this study we performed simulations to investigate the correlation of speech-related artifacts with the respective hemodynamic response in dependency on speech duration and rate of data sampling. Furthermore, we show that prolonged stimulus durations and repetition times of 3 s still allow an effective suppression of speech-related artifacts in fluent as well as in nonfluent speakers. Not only were obvious false activations at high contrast cerebrospinal fluid tissue borders widely eliminated, subjects also displayed consistent activation in speech-related and motor areas. As these results widely resemble those obtained by earlier neuroimaging studies on language production, event-related fMRI seems to be capable of recording neurophysiological correlates of overt speech production.

Adult↗

PubMed2003

Evidence for compensation for stuttering by the right frontal operculum.

There is recent evidence of focal alteration in fibre tracts underlying the left sensorimotor cortex in persistent developmental stuttering (PDS) [Lancet 360 (2002) 380]. If, as proposed, this anatomical abnormality is the cause of PDS, then overactivation in the right hemisphere seen with functional neuroimaging in stutterers may reflect a compensatory mechanism. To investigate this hypothesis, we performed two functional magnetic resonance imaging (fMRI) experiments. The first showed systematic activation of a single focus in the right frontal operculum (RFO) in PDS subjects during reading, which was not observed in controls. Responses in this region were negatively correlated with the severity of stuttering, suggesting compensation rather than primary dysfunction. Negative correlation was also observed during the baseline task that consisted in passive viewing of meaningless signs, indicating that RFO compensation acts independently of specific demands on motor speech output. The second experiment, that involved a covert semantic decision task, confirmed that RFO activation does not require overt utterances or motor output. In combination these findings suggest that the RFO serves a nonspecific compensatory role rather than one restricted to the final stages of speech production.

Adult↗

PubMed2003

Click-evoked ABR at high stimulus repetition rates for neonatal hearing screening.

A new, fast screening algorithm based on auditory brainstem response (ABR) recorded at a high click repetition rate is proposed. Response detection is carried out in the frequency domain by a statistical test procedure which includes the fundamental frequency and the harmonics below 800 Hz. First, the method was tested in 25 young adults. ABRs were recorded in the repetition rate range 20/s to 400/s. With a mean response detection time of 31 s, a click repetition rate of 140/s was found to be the optimum rate among the adult group. The method was then tested using a group of 114 neonates in whom the repetition rate range 60/s to 200/s was examined. At the repetition rate 90/s, which was found to be the optimum rate in neonates, the mean detection time was 24.6 s. In addition to the fast ABR detection, the proposed screening algorithm also allows simultaneous hearing screening of both ears using a one-channel data recording.

Acoustic Stimulation↗

PubMedDate not supplied

The interplay between glottis and vocal tract during the male passaggio.

The transition between 'chest' and 'head' register is essential for male opera singers in order to reach the higher pitches. The 'passaggio', which is a scale passage where this transition takes place, but also a maneuver of register equalization, is typically difficult to learn. Studies on parameters for a definition of this transition are restricted to a small number of singers so far. Audio, electroglottographic, and equivalent subglottic pressure signals of 11 male opera singers were recorded while singing scales on open back vowels and passing the register transition. A spectrum analysis of the audio signal revealed that the second harmonic (H2) dominates in 'chest', resonated by the first formant (F1), together with the fourth harmonic (H4), supported by the second formant (F2). During the passaggio, H2 level decreases because it loses the resonance of F1, while the third harmonic (H3) gains the resonance of F2. At this point the H4 level drops because that harmonic is no longer supported by F2. The transition from 'chest' to 'head' register is marked by characteristic changes in the amplitude patterns of the partials H2, H3, and H4, and the frequency progressions of the first two formants, defining an objective distinction between the two registers.

Adult↗