Comparative Analysis of Audio Processing Techniques on Doppler Radar Signature of Human Walking Motion Using CNN Models.

Artificial intelligence (AI) radar technology offers several advantages over other technologies, including low cost, privacy assurance, high accuracy, and environmental resilience. One challenge faced by AI radar technology is the high cost of equipment and the lack of radar datasets for deep-learning model training. Moreover, conventional radar signal processing methods have the obstacles of poor resolution or complex computation. Therefore, this paper discusses an innovative approach in the integration of radar technology and machine learning for effective surveillance systems that can surpass the aforementioned limitations. This approach is detailed into three steps: signal acquisition, signal processing, and feature-based classification. A hardware prototype of the signal acquisition circuitry was designed for a Continuous Wave (CW) K-24 GHz frequency band radar sensor. The collected radar motion data was categorized into non-human motion, human walking, and human walking without arm swing. Three signal processing techniques, namely short-time Fourier transform (STFT), mel spectrogram, and mel frequency cepstral coefficients (MFCCs), were employed. The latter two are typically used for audio processing, but in this study, they were proposed to obtain micro-Doppler spectrograms for all motion data. The obtained micro-Doppler spectrograms were then fed to a simplified 2D convolutional neural networks (CNNs) architecture for feature extraction and classification. Additionally, artificial neural networks (ANNs) and 1D CNN models were implemented for comparative analysis on various aspects. The experimental results demonstrated that the 2D CNN model trained on the MFCC feature outperformed the other two methods. The accuracy rate of the object classification models trained on micro-Doppler features was 97.93%, indicating the effectiveness of the proposed approach.

Distraction From Itch Shows Brainstem Activation Without Reduction in Experimental Itch Sensation.

The central processing of itch is not completely understood. This is the first study to use functional magnetic resonance imaging (fMRI) to examine the central modulation by distraction of experimentally induced itch. A total of 33 healthy volunteers were examined with fMRI. Periods of itch induction without distraction and itch with distraction by a Stroop task (psychological test, where the participants have to decide if the colour of the writing corresponds to the written word, for example if "red" is written in red or not) were counterbalanced during the scanning to examine task-specific changes in blood oxygenation level dependent-signal. The intensity of the subjects' itch sensation, desire to scratch and pain sensation were evaluated. Distraction by a Stroop task did not reduce itch intensity or urge to scratch. However, the Stroop task led to significantly higher activation of the left brainstem when it followed the "pure" itch sensation. Itch and pain seem to have similar inhibition pathways, particularly concerning brainstem activation during distraction. But as itch sensation, in contrast to pain, could not be sufficiently reduced by distraction, both entities might have different modulation systems.

Sex differences in itch perception and modulation by distraction--an FMRI pilot study in healthy volunteers.

BACKGROUND: Even though itch is a common syndrome of many diseases there is only little knowledge about sex and gender differences in pruritus, especially in central itch perception and modulation. To our knowledge, this is the first fMRI study examining sex differences in perception and its modulation by distraction. METHODS: Experimental itch was induced by application of histamine (0.1 mM) via microdialysis fibers twice at the left forearm and twice at the left lower leg in 33 healthy volunteers (17 females, 16 males). The brain activation patterns were assessed by fMRI during itch without and with distraction (Stroop task). Between the various conditions, subjects were asked to rate itch intensity, desire to scratch and pain intensity. In a second experiment in 10 of the 33 volunteers histamine was replaced by saline solution to serve as control for the 'Stroop' condition. RESULTS: Women generally presented higher itch intensities compared to men during itch over the course of the experiment. A more specific analysis revealed higher itch intensities and desire to scratch in women during experimental induced itch that can be reduced by distraction at the lower legs when itch is followed by 'Stroop'. In contrast, men depicted significant reduction of 'itch' by 'Stroop' at the forearms. Women depicted higher brain activation of structures responsible for integration of sensory, affective information and motor integration/planning during 'itch' and 'Stroop' condition when compared to men. No sex differences were seen in the saline control condition. CONCLUSION: Women and men exhibited localisation dependent differences in their itch perception with women presenting higher itch intensities and desire to scratch. Our findings parallel clinical observations of women reporting higher itch intensities depending on itch localisation and suffering more from itch as compared to men.

Evaluation of the antipruritic effects of topical pimecrolimus in non-atopic prurigo nodularis: results of a randomized, hydrocortisone-controlled, double-blind phase II trial.

BACKGROUND: In the treatment of atopic dermatitis, pimecrolimus has high antipruritic effects. OBJECTIVE: To investigate the efficacy of 1% pimecrolimus cream in comparison to 1% hydrocortisone cream in non-atopic prurigo nodularis (PN). METHODS: A randomized, controlled, double-blind study with intraindividual randomization was done in 30 patients (17 females, 13 males; mean age 58.5 years) with PN. RESULTS: Pruritus intensity decreased significantly (p < 0.001) on both treated sides as early as after 10 days of treatment; scratch lesions improved (p < 0.001). Quality of life as assessed by the Dermatology Life Quality Index improved significantly. However, a significant advantage of pimecrolimus over hydrocortisone was not found. CONCLUSION: The results suggest that the non-steroid pimecrolimus is an effective alternative for PN treatment.

Pruritus assessment in clinical trials: consensus recommendations from the International Forum for the Study of Itch (IFSI) Special Interest Group Scoring Itch in Clinical Trials.

Chronic pruritus is a common symptom and there is an urgent need to test new anti-pruritic substances in high-quality clinical trials. However, no widely accepted standardized and validated method for objectively measuring pruritus is yet available. A special interest group of the International Forum for the Study of Itch has been established to assess scoring methods and questionnaires for use in clinical trials. This paper presents our current recommendations. The set of measures we recommend includes pruritus intensity scales, instruments for assessment of scratch lesions, chronic pruritus course, quality of life and patient benefits.

Cholestatic pruritus: a retrospective analysis on clinical characteristics and treatment response.

BACKGROUND: Chronic cholestatic pruritus (ChP) is caused by various hepatobiliary disorders. This retrospective study describes the distribution of underlying diseases, clinical characteristics and treatment efficacy in a consecutive collective of patients with ChP. PATIENTS AND METHODS: Extensive data from 60 patients with ChP (30 women, 30 men; mean age: 58.0 ± 17.0 years) were retrospectively statistically analyzed concerning demographic data, pruritus characteristics, and response to therapy. RESULTS: In this study population, 40.0% of the patients suffered from hepatitis B or C. Regarding the overall population, pruritus started in 50% of patients after diagnosis of the underlying hepatobiliary disorder. Only in patients with immune-mediated liver diseases did pruritus more often occur before diagnosis (p < 0.05). Only 23.3% of the patients reported an initial palmoplantar pruritus. Along with other drugs, anticonvulsants proved to be an effective treatment regime. CONCLUSIONS: In this study, viral pathogenesis was the most common cause of ChP. Other underlying diseases were represented to a lower extent in the total study population. Overall, the collected clinical parameters in each group were comparable. Thus, it was difficult to draw conclusions on the pathogenesis.

Systemic kappa opioid receptor agonists in the treatment of chronic pruritus: a literature review.

Chronic pruritus is frequently refractory to currently available treatments. Studies suggest that pruritus may arise from an imbalance of the mu- and kappa-opioid receptor system activity in either the skin or the central nervous system. Stimulation of kappa-opioid receptors by their agonists inhibits pruritus in both animals and humans. The antipruritic effect of kappa-opioid receptors agonists can currently be assumed to be related to their binding to kappa-opioid receptors on keratinocytes and cutaneous and/or central itch neurones. To date, several case reports and 2 controlled trials have demonstrated a beneficial effect of systemic kappa-opioid receptor agonists in the treatment of uraemic pruritus, prurigo nodularis, paraneoplastic and cholestatic pruritus. Nalfurafine hydrochloride (Remitch(®)), a selective kappa-opioid receptor agonist, is approved for the treatment of chronic pruritus in Japan. The aim of this review is to provide an overview of the promising role of kappa- opioid receptors and their agonist in the pathophysiology and treatment of pruritus.

Notalgia paraesthetica: a descriptive two-cohort study of 65 patients from Brazil and Germany.

Notalgia paraesthetica is a neuropathic pruritus on the back. The aim of this retrospective study was to examine patient characteristics in a consecutive cohort from Brazil and Germany. A total of 65 patients (49 women, 16 men; age range 25-80 years, mean 56.2 ± 12.7 years; median 57.0 years) were investigated in order to determine the spinal or peripheral origin of notalgia paraesthetica. Protein gene product 9.5-positive intraepidermal nerve fibers were significantly reduced in the pruritic compared with the non-lesional area (p < 0.05). In 32.3% of patients, radiological examinations showed a stenosis and in 47.7% a degeneration. A correlation between the radiological findings and the exact dermatomal localization of notalgia paraesthetica was found in 15.7% of the involved areas. The significant reduction in intraepidermal nerve fiber density suggests that damage to the peripheral nerves is a more important aetiological factor than spinal changes in notalgia paraesthetica.

Assessment of pruritus intensity: prospective study on validity and reliability of the visual analogue scale, numerical rating scale and verbal rating scale in 471 patients with chronic pruritus.

The most commonly used tool for self-report of pruritus intensity is the visual analogue scale (VAS). Similar tools are the numerical rating scale (NRS) and verbal rating scale (VRS). In the present study, initiated by the International Forum for the Study of Itch assessing reliability of these tools, 471 randomly selected patients with chronic itch (200 males, 271 females, mean age 58.44 years) recorded their pruritus intensity on VAS (100-mm line), NRS (0-10) and VRS (four-point) scales. Re-test reliability was analysed in a subgroup of 250 patients after one hour. Statistical analysis showed a high reliability and concurrent validity (r>0.8; p<0.01) for all tools. Mean values of all scales showed a high correlation. In conclusion, high reliability and concurrent validity was found for VAS, NRS and VRS. On re-test, higher correlation and less missing values were observed. A training session before starting a clinical trial is recommended.

Visual analogue scale: evaluation of the instrument for the assessment of pruritus.

The aim of this study was to evaluate the visual analogue scale (VAS) as a method of pruritus assessment. A total of 310 subjects with pruritic dermatoses (148 Caucasian subjects and 162 Asian subjects) were recruited. The patients assessed pruritus intensity using the horizontal and vertical VAS, numeric rating scale (NRS) and verbal rating scale (VRS). All scales showed very good reproducibility (intraclass coefficient (ICC) > 0.8). No significant differences were found between the horizontal and vertical VAS (5.3 ± 2.9 vs. 5.3 ± 3.0 points, p = 0.34). Using NRS, patients rated their pruritus significantly higher than with VAS (5.7 ± 2.6 points, p < 0.01). VRS showed the highest correlation with NRS (R = 0.82, p < 0.001), followed by horizontal (R = 0.75, p < 0.001) and vertical VAS (R=0.74, p < 0.001). Based on detailed analysis following VAS categories were proposed: 0 = no pruritus, > 0-< 4 points = mild pruritus, ≥ 4-< 7 points = moderate pruritus, ≥ 7-< 9 points = severe pruritus, and ≥ 9 points = very severe pruritus. In conclusion, the VAS is a valuable method of pruritus measurement.

Brachioradial pruritus as a result of cervical spine pathology: the results of a magnetic resonance tomography study.

BACKGROUND: Brachioradial pruritus (BRP) describes a rare form of itching occurring at the dorsolateral part of the forearms. Recent case reports suggest that BRP may be attributed to cervical lesions or spine neoplasms. OBJECTIVE: We sought to determine the incidence of cervical spine changes in BRP and to correlate the localization of spinal lesions with the dermatomal presence of pruritus. METHODS: Magnetic resonance tomography (MRT) of the cervical spinal cord, a chest x-ray, and a skin biopsy were performed in 41 patients (28 female, 13 male; 59.0 ± 10.6 years) with BRP. Patients completed an itch questionnaire (NeuroDerm Questionnaire) that included a dermatome chart and the Northwick Park Neck Pain Questionnaire. RESULTS: The patients marked the locations C5 (90.2%) and C6 (100%) on the dermatome chart. All patients had detectable MRT changes. In 80.5% of the patients, stenosis of the intervertebral foramen or protrusions of the cervical disk led to nerve compression. The location of the nerve compression lesions correlated significantly with the dermatomal localization of the pruritus (Spearman correlation coefficient 0.893; P < .01). No spinal neoplasm was observed, and 19.5% of the patients had degenerative changes without significant correlation to the dermatomal localization of pruritus. LIMITATION: No healthy control group without pruritus was investigated. CONCLUSION: BRP may result from cervical nerve compression, and rarely, it may also stem from degenerative changes. Our findings suggest that even slight cervical changes detected on MRT may alter itch afferents and lead to BRP. Spinal cord tumors are rare and should be ruled out by a cervical spine MRT.

Aquagenic pruritus: associated diseases and clinical pruritus characteristics.

BACKGROUND: Aquagenic pruritus (AP) can be induced by systemic diseases. The distribution of underlying diseases in a representative patient collective has not been investigated. This retrospective study aimed to determine the frequency and pruritus-specific parameter of systemic diseases in a series of patients. PATIENTS AND METHODS: Data of 39 patients with AP (24 f, 15 m; mean age: f: 51.3 ± 20.1, m: 57.2 ± 15.0 years) were obtained and statistically evaluated as follows: demographic data, pruritus characteristics, underlying diseases, family history. RESULTS: 30.8 % of patients exhibited polycythemia vera or myelofibrosis (Group 1: G1), in 69.2 % (G2) no underlying disease was found. 25.6 % had lactose intolerance as possible contributing factor. Women were significantly more common in G2 (p < 0.01), with a lower mean age (p < 0.01) and longer duration of AP (18.9 years, p < 0.01). CONCLUSIONS: AP occurs frequently with polycythemia vera. Other underlying diseases are rare; in over half of the patients no cause can be detected. In 25 % lactose intolerance is present which possibly acts as co-factor. Demographic parameters (age, gender) allow estimation of the possible underlying disease in AP. Pruritus characteristics are similar in all groups and not helpful in determining the origin of AP.

Antipruritic treatment with systemic µ-opioid receptor antagonists: a review.

During the past two decades, systemic µ-opioid receptor antagonists (MORA) have been used in the treatment of various forms of chronic pruritus. In a number of case reports, case series, and controlled trials, treatment with MORA has demonstrated considerable antipruritic effects. In double-blind controlled studies, significant antipruritic relief has been achieved by MORA in cholestatic pruritus, chronic urticaria, and atopic dermatitis. In case reports and case series, antipruritic efficacy of MORA has been reported in prurigo nodularis, mycosis fungoides, postburn pruritus, aquagenic pruritus, hydroxyethyl starch-induced pruritus, and pruritus of unknown origin. However, most of the evidence remains anecdotal, the design of these trials varies, and comparison of results is difficult. In this review we aim to present an overview of these reports and to assess the evidence for the antipruritic action of the drugs naloxone, nalmefene, and naltrexone, which are currently in use for the treatment of chronic pruritus of different origins. We will also evaluate recommendations for the use of MORA in daily medical practice.

Low density of sympathetic nerve fibers relative to substance P-positive nerve fibers in lesional skin of chronic pruritus and prurigo nodularis.

BACKGROUND: In prurigo nodularis (PN), an increase in the density of dermal substance P-positive (SP+) sensory nerve fibers has been demonstrated. In addition, the density of sympathetic nerve fibers is unchanged. OBJECTIVE: We aimed to investigate the density and balance of sensory and sympathetic dermal nerves in pruritus on normally appearing skin in comparison to PN. METHODS: In a parallel investigation in lesional and non-lesional skin routine histological and immunofluorescence staining against SP and tyrosine hydroxylase (TH) were performed. RESULTS: We found an increased density of dermal SP+ nerve fibers in PN and also in pruritus relative to sympathetic nerve fibers in affected areas compared to the unaffected site. The density of SP+ and TH+ nerves did not correlate with clinical parameters such as itch quality, duration or intensity. Sparse lymphocytic infiltration as found in affected pruritus skin may be a source of nerve growth factor and explain the hyperinnervation. CONCLUSION: Similar to the situation in PN, chronic pruritus lesions also demonstrate a preponderance of SP+ sensory nerve fibers relative to sympathetic nerve fibers, which probably acts as a causal pro-inflammatory signal in development of pruritus. These findings suggest new therapeutic approaches in patients with chronic pruritus.

Adjuvant topical therapy with a cannabinoid receptor agonist in facial postherpetic neuralgia.

BACKGROUND: Postherpetic neuralgia is a frequent adverse event in herpes zoster patients and difficult to treat. Conventional analgetic therapy often fails to reduce the burning pain transmitted by unmyelinated nerve fibers. These nerves express cannabinoid receptors which exert a role in modulation of nociceptive symptoms. Therefore, topical therapy with cannabinoid receptor agonist seems likely to suppress local burning pain. PATIENTS AND METHODS: In an open-labeled trial, 8 patients with facial postherpetic neuralgia received a cream containing the cannabinoid receptor agonist N-palmitoylethanolamine. The course of symptoms was scored with the visual analog scale. RESULTS: 5 of 8 patients (62.5 %) experienced a mean pain reduction of 87.8 %. Therapy was tolerated by all patients. No unpleasant sensations or adverse events occurred. CONCLUSIONS: Topical cannabinoid receptor agonists are an effective and well-tolerated adjuvant therapy option in postherpetic neuralgia.