Amarjargal Nyamaa

Dr. Amarjargal Nyamaa

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Research Focus & Metrics

Academic Career Length

19Years (2008-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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16 February 2022 in Brain Sciences
Verified
Journal Article
Open access
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Petra BrüggemannPetra Brüggemann
Petra Brüggemann
WMWilhelm Mebus
Wilhelm Mebus
BBBenjamin Boecking
Benjamin Boecking
ANAmarjargal Nyamaa
Amarjargal Nyamaa
Uli NiemannUli Niemann
Uli Niemann
Birgit MazurekBirgit Mazurek
Birgit Mazurek
Objectives: (1) To determine which psychosocial aspects predict tinnitus-related distress in a large self-reported dataset of patients with chronic tinnitus, and (2) to identify underlying constructs by means of factor analysis. Methods: A cohort of 1958 patients of the Charité Tinnitus Center, Berlin completed a large questionnaire battery that comprised sociodemographic data, tinnitus-related distress, general psychological stress experience, emotional symptoms, and somatic complaints. To identify a construct of “tinnitus-related distress”, significant predictive items were grouped using factor analysis. Results: For the prediction of tinnitus-related distress (linear regression model with R2 = 0.7), depressive fatigue symptoms (concentration, sleep, rumination, joy decreased), the experience of emotional strain, somatization tendencies (pain experience, doctor contacts), and age appeared to play a role. The factor analysis revealed five factors: “stress”, “pain experience”, “fatigue”, “autonomy”, and low “educational level”. Conclusions: Tinnitus-related distress is predicted by psychological and sociodemographic indices. Relevant factors seem to be depressive exhaustion with somatic expressions such as sleep and concentration problems, somatization, general psychological stress, and reduced activity, in addition to higher age.

1 January 2009 in Physiological Research
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Journal Article
Open access
ANAmarjargal Nyamaa
Amarjargal Nyamaa
NAN Andreeva
N Andreeva
JGJ Gross
J Gross
HHH Haupt
H Haupt
JFJulia Fuchs
Julia Fuchs
Birgit MazurekBirgit Mazurek
Birgit Mazurek
Ischemia can contribute to the inner ear pathology and hearing loss. To determine the susceptibility of inner and outer hair cells (IHCs/OHCs) to ischemic and post-ischemic period, we used organotypic cultures of the organ of Corti isolated from P3 rats as an in vitro model of inner ear ischemia (oxygen-glucose deprivation, OGD). We identified the hair cells (HCs) by phalloidin staining. The cells with damaged cellular membrane integrity were identified by propidium iodide (PI)-exclusion assay. The cells with fragmented chromosomal DNA were detected by TUNEL assay. Organotypic cultures were subjected to a mild (3 h duration) or severe (4 h duration) OGD, followed by a recovery period of 21 h and 20 h, respectively. Mild OGD induced a loss of 10-20 % HCs, whereas severe OGD induced loss of 35 % HCs. We confirmed that OHCs are less vulnerable to OGD than IHCs. Of all missing OHCs, 80-90 % was lost during the OGD period and 10-20 % during the recovery period. In contrast, the loss of IHCs was equal during both experimental periods. The OGD period was mainly associated with PI-positive nuclei. TUNELpositive nuclei were a minor fraction during the OGD period and increased during the recovery period, indicating the progression of DNA fragmentation. Our results implicate a differential susceptibility of IHCs and OHCs during and after ischemia-like insult, which may be of therapeutic consequence.

4 October 2022 in Journal of Clinical Medicine
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BBBenjamin Boecking
Benjamin Boecking
SPStamatina Psatha
Stamatina Psatha
ANAmarjargal Nyamaa
Amarjargal Nyamaa
Juliane Dettling-PapargyrisJuliane Dettling-Papargyris
Juliane Dettling-Papargyris
CFChristine Funk
Christine Funk
Birgit MazurekBirgit Mazurek
Birgit Mazurek
Background: Hearing aids (HAs) can improve tinnitus-related distress (TRD) and speech-comprehension (SC) in silence or at 55 dB noise-interference (SC_55 dB) in patients with chronic tinnitus and mild-to-moderate hearing loss. However, the role of HA use time in relation to psychological, audiological, or self-reported tinnitus characteristics is under-investigated. Methods: We examine 177 gender-stratified patients before (t1) and after an intervention comprising binaural DSLchild algorithm-based HA fitting and auditory training (t2) and at a 70-day follow up [t3]. HA use time was retrospectively retrieved (at t2) for the pre-post- and (at t3) post-follow up periods. General linear models investigated HA use time in relation to (1) general audiological, (2) tinnitus-related audiological, (3) tinnitus-related self-report, and (4) distress-related self-report indices before and after treatment, where applicable. Receiver operator characteristic analyses identified optimal HA use time for hereby-mediated treatment changes. Results: At t1 and t2, psychological, but not audiological indices causally influenced prospective HA use time—except for SC_55 dB at t1, which, however, correlated with patients’ anxiety, depressivity, and psychological distress levels. Correlations did not differ between patient subgroups defined by categorical tinnitus-related audiological or self-report indices. HA use time partly mediated treatment-related improvement in TRD, but not SC. Optimal use amounted to 9.5–10.5 h/day. Conclusions: An awareness of psychological influences may help clinicians facilitate HA use and, thereby, TRD improvement with hearing amplification.

22 March 2022 in Journal of Clinical Medicine
Verified
Journal Article
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BBBenjamin Boecking
Benjamin Boecking
LRLeonie Rausch
Leonie Rausch
SPStamatina Psatha
Stamatina Psatha
ANAmarjargal Nyamaa
Amarjargal Nyamaa
Juliane Dettling-PapargyrisJuliane Dettling-Papargyris
Juliane Dettling-Papargyris
Birgit MazurekBirgit Mazurek
Birgit Mazurek
Background: The psychological effects of hearing aids and auditory training are underinvestigated. Objective: To assess the short- and long-term effects of an industry-developed auditory training on tinnitus-related distress, perceived stress, and psychological epiphenomena in patients with chronic tinnitus and mild-to-moderate hearing loss. Method: One-hundred-seventy-seven gender-stratified patients were randomized to an immediate [IIG] or delayed [DIG] intervention group. Following binaural hearing aid fitting, participants completed a CD-enhanced 14-days self-study program. Applying a randomized-controlled cross-over design, psychological measures were obtained at four times: pre-treatment/wait [IIG: t1; DIG: wait], post-treatment/pre-treatment [IIG: t2; DIG: t1], follow-up/post-treatment [IIG: t3; DIG: t2], and follow-up [DIG: t3]. Between- and within-group analyses investigated treatment-related effects and their stability at a 70-day follow-up. Results: Overall, distress symptom severity was mild. Unlike the DIG, the IIG showed significant improvements in tinnitus-related distress. Some psychological epiphenomena, notably anxiety, slightly improved in both groups. Within-group analyses demonstrated the stability of the tinnitus-distress-related effects, alongside uncontrolled improvements of perceived stress and mood-related symptoms at follow-up. Conclusions: The investigated hearing therapy lastingly improves tinnitus-related distress in mildly distressed patients with chronic tinnitus and mild-to-moderate hearing loss. Beneficial psychological knock-on effects deserve further investigation.

28 May 2022 in Nutrients
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Journal Article
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BBBenjamin Boecking
Benjamin Boecking
SKSven Klasing
Sven Klasing
MWMichael Walter
Michael Walter
Petra BrüggemannPetra Brüggemann
Petra Brüggemann
ANAmarjargal Nyamaa
Amarjargal Nyamaa
Birgit MazurekBirgit Mazurek
Birgit Mazurek
Little is known about molecular correlates of chronic tinnitus. We examined interrelationships between vascular–metabolic risk factors, perceived stress, and other routine blood values in patients with chronic tinnitus. Two-hundred patients (51% female) were screened for 49 blood parameters pertaining to vascular–metabolic risk, immune function, and redox processes. They further completed perceived stress- and tinnitus-related distress questionnaires. Following descriptive analyses, gender-specific sets of age- and tinnitus-severity-adjusted regression models investigated associations between perceived stress and blood parameters. Patients reported mildly elevated levels of perceived stress. Elevated levels of total cholesterol (65% and 61% of female and male patients, respectively), non-HDL-c (43/50%), LDL-c (56/59%), and lipoprotein_a (28/14%) were accompanied by high rates of overweight (99/100%) and smoking (28/31%). A low-level inflammatory state was accompanied by reduced reactive oxygen species (ROS)-neutralizing capacity (reduced co-enzyme Q10 and SOD1 levels). Most vascular risk factors were not correlated with perceived stress, except for fibrinogen (ß = −0.34) as well as C-reactive protein (ß = −0.31, p < 0.05) in men, and MCV (ß = −0.26, p < 0.05) in women. Interrelations between blood parameters and stress levels need to be investigated within psychobehavioural frameworks across varying distress levels. Alongside psychological interventions, a low-level inflammatory state may be a route for pharmacological therapeutics.

5 September 2022 in Journal of Clinical Medicine
Verified
Journal Article
Open access
PDF file
BBBenjamin Boecking
Benjamin Boecking
LRLeonie Rausch
Leonie Rausch
SPStamatina Psatha
Stamatina Psatha
ANAmarjargal Nyamaa
Amarjargal Nyamaa
Juliane Dettling-PapargyrisJuliane Dettling-Papargyris
Juliane Dettling-Papargyris
Birgit MazurekBirgit Mazurek
Birgit Mazurek
Background: Patients with chronic tinnitus and mild-to-moderate hearing loss (HL) can experience difficulties with speech comprehension (SC). The present study investigated SC benefits of a two-component hearing therapy. Methods: One-hundred-seventy-seven gender-stratified patients underwent binaural DSLchild-algorithm-based hearing aid (HA) fitting and conducted auditory training exercises. SC was measured at four timepoints under three noise interference conditions each (0, 55, and 65 dB): after screening (t0; without HAs), HA- fitting (t1), additional auditory training (t2), and at 70-day follow-up (t3). Repeated-measure analyses of covariance investigated the effects of HAs (t0–t1), auditory training (t1–t2), and the stability of the combined effect (t2–t3) on SC per noise interference level and HL subgroup. Correlational analyses examined associations between SC, age, and psychological indices. Results: Patients showed mildly elevated tinnitus-related distress, which was negatively associated with SC in patients with mild but not moderate HL. At 0 dB, the intervention lastingly improved SC for patients with mild and moderate HL; at 55 dB, for patients with mild HL only. These effects were mainly driven by HAs. Conclusions: The here-investigated treatment demonstrates some SC-benefit under conditions of no or little noise interference. The auditory training component warrants further investigation regarding non-audiological treatment outcomes.