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Mathematical Biosciences and... Feb 2022Serotonin, dopamine and norepinephrine are monoamine neurotransmitters that modulate our mood state. Hence, imbalances in the levels of these neurotransmitters have been...
Serotonin, dopamine and norepinephrine are monoamine neurotransmitters that modulate our mood state. Hence, imbalances in the levels of these neurotransmitters have been linked to the incidence of several psychiatric disorders. Here, a mathematical model written in terms of ordinary differential equations is proposed to represent the interaction of these three neurotransmitters. It is analytically and numerically shown that this model can experience a Hopf bifurcation. Thus, by varying a parameter value, the neurotransmitter levels can change from a steady state to an oscillatory behavior, which may be at least a partial explanation of the mood swings observed in depressed people.
Topics: Dopamine; Humans; Models, Theoretical; Neurotransmitter Agents; Serotonin; Systems Analysis
PubMed: 35341287
DOI: 10.3934/mbe.2022187 -
Cognitive, Affective & Behavioral... Aug 2021The right hemisphere is involved with the integrative processes necessary to achieve global coherence during reasoning and discourse processing. Specifically, the right...
The right hemisphere is involved with the integrative processes necessary to achieve global coherence during reasoning and discourse processing. Specifically, the right temporal lobe has been proven to facilitate the processing of distant associate relationships, such as generating novel ideas. Previous studies showed a specific swing of alpha and gamma oscillatory activity over the right parieto-occipital lobe and the right anterior temporal lobe respectively, when people solve semantic problems with a specific strategy, i.e., insight problem-solving. In this study, we investigated the specificity of the right parietal and temporal lobes for semantic integration using transcranial Random Noise Stimulation (tRNS). We administered a set of pure semantics (i.e., Compound Remote Associates [CRA]) and visuo-semantic problems (i.e., Rebus Puzzles) to a sample of 31 healthy volunteers. Behavioral results showed that tRNS stimulation over the right temporal lobe enhances CRA accuracy (+12%), while stimulation on the right parietal lobe causes a decrease of response time on the same task (-2,100 ms). No effects were detected for Rebus Puzzles. Our findings corroborate the involvement of the right temporal and parietal lobes when solving purely semantic problems but not when they involve visuo-semantic material, also providing causal evidence for their postulated different roles in the semantic integration process and promoting tRNS as a candidate tool to boost verbal reasoning in humans.
Topics: Humans; Parietal Lobe; Problem Solving; Semantics; Temporal Lobe; Transcranial Direct Current Stimulation
PubMed: 33796985
DOI: 10.3758/s13415-021-00885-x -
Der Nervenarzt Mar 2024Premenstrual syndrome and premenstrual dysphoric disorder become episodically manifest during the second half of the female menstrual cycle and are characterized by... (Review)
Review
Premenstrual syndrome and premenstrual dysphoric disorder become episodically manifest during the second half of the female menstrual cycle and are characterized by psychological and physical symptoms causing relevant functional and social impairments. Mood swings, depression and dysphoria are associated depressive symptoms. Therefore, affective disorders should be considered as a differential diagnosis. Of women in reproductive age 3-8% suffer from premenstrual syndrome and 2% of women are affected by premenstrual dysphoric disorder. Genetic and sociobiographical risk factors are discussed. Furthermore, genetic polymorphisms of specific hormone receptors are considered to be genetic risk factors. From a pathophysiological perspective premenstrual syndrome and premenstrual dysphoric disorder are caused by a complex interaction between cyclic changes of ovarian steroids and central neurotransmitters. An imbalance of estrogen and progesterone in the luteal phase is believed to cause the symptoms. Therefore, the first treatment approach consists of regulation of the menstrual cycle or luteal support with progesterone or synthetic progestins even if their effectiveness has not yet been proven in randomized controlled studies and meta-analyses. The administration of combined oral contraceptives is also an option. Especially treatment with selective serotonin reuptake inhibitors (SSRI) represent an evidence-based approach. In severe cases the administration of gonadotropin releasing hormone (GnRH) agonists with add back treatment can also be considered. In the field of affective disorders premenstrual syndromes represent clinically relevant differential diagnoses and comorbidities, which confront the treating physician with particular clinical challenges. Therefore, this literature review gives the readership a clinical orientation for dealing with these disorders.
Topics: Female; Humans; Child, Preschool; Premenstrual Dysphoric Disorder; Progesterone; Premenstrual Syndrome; Mood Disorders; Anxiety
PubMed: 38393358
DOI: 10.1007/s00115-024-01625-5 -
Journal of Neuroengineering and... Sep 2022Transfemoral prosthesis users' high fall rate is related to increased injury risk, medical costs, and fear of falling. Better understanding how stumble conditions (e.g.,...
BACKGROUND
Transfemoral prosthesis users' high fall rate is related to increased injury risk, medical costs, and fear of falling. Better understanding how stumble conditions (e.g., participant age, prosthesis type, side tripped, and swing phase of perturbation) affect transfemoral prosthesis users could provide insight into response deficiencies and inform fall prevention interventions.
METHODS
Six unilateral transfemoral prosthesis users experienced obstacle perturbations to their sound limb in early, mid, and late swing phase. Fall outcome, recovery strategy, and kinematics of each response were recorded to characterize (1) recoveries versus falls for transfemoral prosthesis users and (2) prosthesis user recoveries versus healthy adult recoveries.
RESULTS
Out of 26 stumbles, 15 resulted in falls with five of six transfemoral prosthesis users falling at least once. By contrast, in a previously published study of seven healthy adults comprising 214 stumbles using the same experimental apparatus, no participants fell. The two oldest prosthesis users fell after every stumble, stumbles in mid swing resulted in the most falls, and prosthesis type was not related to strategy/fall outcomes. Prosthesis users who recovered used the elevating strategy in early swing, lowering strategy in late swing, and elevating or lowering/delayed lowering with hopping in mid swing, but exhibited increased contralateral (prosthetic-side) thigh abduction and trunk flexion relative to healthy controls. Falls occurred if the tripped (sound) limb did not reach ample thigh/knee flexion to sufficiently clear the obstacle in the elevating step, or if the prosthetic limb did not facilitate a successful step response after the initial sound-side elevating or lowering step. Such responses generally led to smaller step lengths, less anterior foot positioning, and more forward trunk flexion/flexion velocity in the resulting foot-strikes.
CONCLUSIONS
Introducing training (e.g., muscle strength or task-specific motor skill) and/or modifying assistive devices (e.g., lower-limb prostheses or exoskeletons) may improve responses for transfemoral prosthesis users. Specifically, training or exoskeleton assistance could help facilitate sufficient thigh/knee flexion for elevating; training or prosthesis assistance could provide support-limb counteracting torques to aid in elevating; and training or prosthesis assistance could help initiate and safely complete prosthetic swing.
Topics: Adult; Artificial Limbs; Biomechanical Phenomena; Fear; Gait; Humans; Walking
PubMed: 36151561
DOI: 10.1186/s12984-022-01070-y -
Life (Basel, Switzerland) Jun 2024Menopausal women experience changes in ovarian activity and fluctuating hormone levels. The aim of this study was to detect ongoing sleep and nutritional problems in...
Menopausal women experience changes in ovarian activity and fluctuating hormone levels. The aim of this study was to detect ongoing sleep and nutritional problems in postmenopausal women. This study was conducted with 62 postmenopausal women who had been diagnosed with major depressive disorder, were aged 42-64, were not dieting for at least 1 month, and had been using antidepressants for at least 6 months. The Pittsburgh Sleep Quality Index and Depression Anxiety Stress Scale-42 were used. Anthropometric measurements were taken and body composition analysis was performed. The prevalence of obesity and overweight were 12.9% and 71%, respectively. Hot flashes, night sweats, and mood swing were more common in those who had been through menopause for <5 years. Also, the PSQI, Depression, and Stress scores of those women were higher. Women who had been menopausal for ≥5 years had a higher BMI, waist/hip ratio, and fat mass and better sleep quality and lower daytime dysfunction according to the PSQI. Energy and fat intake were higher, while protein, vitamin C, and calcium intakes were lower in women who had been menopausal for ≥5 years. It is crucial for healthcare professionals to review approaches for early and late menopausal periods and to individualize treatment options, especially in patients whose symptoms persist.
PubMed: 38929757
DOI: 10.3390/life14060775 -
Frontiers in Endocrinology 2020Exogenous glucocorticoids are widely used in the clinic for the treatment of inflammatory disorders and hematological cancers. Unfortunately, their use is associated... (Review)
Review
Exogenous glucocorticoids are widely used in the clinic for the treatment of inflammatory disorders and hematological cancers. Unfortunately, their use is associated with debilitating side effects, including hyperglycemia, osteoporosis, mood swings, and weight gain. Despite the continued efforts of pharma as well as academia, the search for so-called selective glucocorticoid receptor modulators (SEGRMs), compounds with strong anti-inflammatory or anti-cancer properties but a reduced number or level of side effects, has had limited success so far. Although monoclonal antibody therapies have been successfully introduced for the treatment of certain disorders (such as anti-TNF for rheumatoid arthritis), glucocorticoids remain the first-in-line option for many other chronic diseases including asthma, multiple sclerosis, and multiple myeloma. This perspective offers our opinion on why a continued search for SEGRMs remains highly relevant in an era where small molecules are sometimes unrightfully considered old-fashioned. Besides a discussion on which bottlenecks and pitfalls might have been overlooked in the past, we elaborate on potential solutions and recent developments that may push future research in the right direction.
Topics: Animals; Anti-Inflammatory Agents; Antineoplastic Agents; Arthritis, Rheumatoid; Drug Discovery; Glucocorticoids; Humans; Ligands; Osteoporosis; Receptors, Glucocorticoid; Tumor Necrosis Factor-alpha
PubMed: 33071974
DOI: 10.3389/fendo.2020.559673 -
Journal of Patient-reported Outcomes Feb 2023Patient-reported outcome (PRO) measures are important to consider when evaluating treatments, yet there are no PRO measures for patients with acromegaly that have been...
BACKGROUND
Patient-reported outcome (PRO) measures are important to consider when evaluating treatments, yet there are no PRO measures for patients with acromegaly that have been developed in accordance with US Food and Drug Administration guidance. Acromegaly is a rare, chronic condition caused by hypersecretion of growth hormone. Disease activity is monitored by measurement in serum of growth hormone and insulin-like growth factor-I. The objectives of this research were to develop the Acromegaly Symptom Diary (ASD), establish a scoring algorithm, and evaluate the psychometric measurement properties of the ASD.
METHODS
Semistructured interviews consisting of concept elicitation and cognitive debriefing components were conducted with 16 adult participants with acromegaly. The concept elicitation component identified symptoms important to individuals with acromegaly. The cognitive debriefing component gathered information about the participants' experience with each proposed item of the ASD, their thought process for answering each question, and their interpretation of the items. The psychometric properties of the draft ASD were then evaluated using data from the ACROBAT Evolve (NCT03792555; n = 13) and ACROBAT Edge (NCT03789656; n = 47) clinical trials.
RESULTS
The 16 participants from the interviews described ongoing symptoms, with the most frequently reported being joint pain (n = 13) and fatigue (n = 12), followed by swelling (n = 8), headache (n = 7), and mood swings (n = 6), and were able to interpret and understand the ASD items and had no issues with the 24-hour recall period. From data collected in the clinical studies, the psychometric properties of internal consistency (0.91 - 0.80), test-retest reliability with item-level and total ASD scores (> 0.70), baseline construct validity (r ≥ |0.38|) across scales, and responsiveness to change (r = 0.52-0.56) were supported for the ASD. The proposed preliminary threshold range to characterize a meaningful change from the patients' perspective for the ASD total is a 4- to 6-point change for improvement or worsening out of a total score of 70.
CONCLUSION
These findings provide qualitative and quantitative evidence to support the ASD as fit for the purpose of evaluating the symptom experience of patients with acromegaly in clinical trials.
Topics: Adult; Humans; Acromegaly; Reproducibility of Results; Surveys and Questionnaires; Mental Recall; Growth Hormone
PubMed: 36792844
DOI: 10.1186/s41687-023-00541-7 -
Journal of Biomechanics Jan 2022Motor variability is a fundamental feature of gait. Altered arm swing and lower limb asymmetry (LLA) may be contributing factors having been shown to affect the...
Motor variability is a fundamental feature of gait. Altered arm swing and lower limb asymmetry (LLA) may be contributing factors having been shown to affect the magnitude and dynamics of variability in spatiotemporal and trunk motion. However, the effects on lower limb joints remain unclear. Full-body kinematics of 15 healthy young adults were recorded during treadmill walking using the Computer-Assisted Rehabilitation Environment system. Participants completed six trials, combining three arm swing (AS) amplitude (normal, active, held) and two LLA (symmetrical, asymmetrical) conditions. The mean standard deviation (meanSD), maximum Lyapunov exponent (λ), detrended fluctuation analysis scaling exponent of range of motion (DFAα), and sample entropy (SaEn) were computed for tridimensional trunk, pelvis, and lower limb joint angles, and compared using repeated-measures ANOVAs. Relative to normal AS, active AS increased meanSD of all joint angles, λ of frontal plane hip and ankle angles, and SaEn of sagittal plane ankle angles. Active AS, however, did not affect λ or SaEn of trunk or pelvis angles. LLA increased meanSD of sagittal plane joint angles, λ of Euclidean norm trunk angle and of lower limb joint angles, and SaEn of ankle dorsiflexion/ plantarflexion, but decreased SaEn of tridimensional trunk angles and hip rotation in the slower moving leg. Alterations in lower limb variability with active AS and LLA suggest that young adults actively exploit their lower limb redundancies to maintain gait. This appears to preserve trunk stability and regularity during active AS but not during LLA.
Topics: Ankle Joint; Biomechanical Phenomena; Gait; Humans; Lower Extremity; Walking; Young Adult
PubMed: 34749161
DOI: 10.1016/j.jbiomech.2021.110855 -
Orthopaedic Surgery Sep 2022To determine whether unilateral chronic ankle instability (CAI) affects the kinematics of the uninjured contralateral ankle.
OBJECTIVE
To determine whether unilateral chronic ankle instability (CAI) affects the kinematics of the uninjured contralateral ankle.
METHODS
In this case-control study, 15 adult patients with unilateral CAI and 15 healthy controls were studied. Both the unstable and uninjured ankles in patients with unilateral CAI (CAI group, n = 15) were compared with that of healthy individuals (control group, n = 15). Applying body photo-reflective markers, the participant's motion during gait was measured. Biomechanical variables including overall ankle-toe angle, linear velocity, linear acceleration, angular velocity, angular acceleration, range of motion (RoM) in dorsiplantar flexion, and inversion-eversion at initial contact, loading response, mid-stance, terminal stance, pre-swing, and swing phase of the gait were measured.
RESULTS
In patients with CAI, the injured and uninjured ankles were significantly different regarding angle-toe angle, inversion-eversion RoM, dorsiplantar flexion in mid-stance, inversion-eversion at initial contact and terminal stance as well as the pre-swing and swing phases (p < 0.01). The uninjured ankles of patients showed lower ankle-toe velocity (p = 0.01) and acceleration (p = 0.01) compared to both the left and right ankles of the controls. In addition, the uninjured ankles of the patients showed decreased ankle dorsiflexion and increased inversion during initial contact, loading response, mid-stance, terminal stance, pre-swing, and swing compared to the control group (p < 0.017).
CONCLUSION
The results suggest that unilateral CAI can affect gait biomechanics in the contralateral uninjured ankle. Left unaddressed, unilateral CAI may lead to increased morbidity to the contralateral uninjured side. When surgery is not preferred for the management of unilateral CAI, rehabilitation protocols should focus on both sides.
Topics: Adult; Ankle; Ankle Joint; Biomechanical Phenomena; Case-Control Studies; Chronic Disease; Gait; Humans; Joint Instability
PubMed: 35852096
DOI: 10.1111/os.13307 -
BMC Sports Science, Medicine &... Nov 2023The effect of listening to audiobooks, podcasts, and other audio files while walking on gait performance has not been well studied. Although the number of audio users is...
BACKGROUND
The effect of listening to audiobooks, podcasts, and other audio files while walking on gait performance has not been well studied. Although the number of audio users is growing annually. Evidence suggests that a posture-first strategy contributes to gait stability in healthy individuals during dual-task conditions, but this effect may be diminished when the cognitive task is consciously prioritized.
OBJECTIVES
To study the effect of listening to an audiobook while walking, as a daily life-like dual-task, on spatiotemporal gait parameters.
METHODS
Forty young healthy (24.05 ± 3.66) subjects participated in the study. Spatiotemporal gait parameters were measured for 5 min on a treadmill once without (single-task) and once while listening to an audiobook through over-ear headphones (dual-task). Measured parameters included spatiotemporal parameters, gait phases, maximum pressure, and dual-task cost. Data were statistically analyzed using SPSS software.
RESULTS
There were no significant differences in any of the studied parameters between the single- and dual-task conditions, even though the subjective cognitive load of listening to audiobooks while walking was high. However, participants with different habits had significant differences in gait phases and maximum pressure. Rare listeners had a shorter stance phase, a longer swing phase, and a higher maximum pressure on the dominant heel. They also had significant differences in dual-task costs.
CONCLUSION
No differences in the spatiotemporal gait parameters for walking with and without listening to audiobooks, as a daily life-like dual-task, were observed. However, the difference between participants who listened rarely and participants who listened often may confirm the "posture first" strategy in young healthy people.
TRIAL REGISTRATION
DRKS00025837, retrospectively registered on 23.11.2021.
PubMed: 38001528
DOI: 10.1186/s13102-023-00773-6