Browsing by Author "Töyräs, Juha"
Now showing items 1-20 of 22
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Accurate Deep Learning-Based Sleep Staging in a Clinical Population with Suspected Obstructive Sleep Apnea
Korkalainen, Henri; Aakko, Juhani; Nikkonen, Sami; Kainulainen, Samu; Leino, Akseli; Duce, Brett; Afara, Isaac Oluwaseun; Myllymaa, Sami; Töyräs, Juha; Leppänen, Timo (Institute of Electrical and Electronics Engineers (IEEE), 2019)The identification of sleep stages is essential in the diagnostics of sleep disorders, among which obstructive sleep apnea (OSA) is one of the most prevalent. However, manual scoring of sleep stages is time-consuming, ...Tieteelliset aikakauslehtiartikkelit
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Bayesian Network Model to Evaluate the Effectiveness of Continuous Positive Airway Pressure Treatment of Sleep Apnea
Ryynänen, Olli-Pekka; Leppänen, Timo; Kekolahti, Pekka; Mervaala, Esa; Töyräs, Juha (The Korean Society of Medical Informatics (KAMJE), 2018)Objectives The association between obstructive sleep apnea (OSA) and mortality or serious cardiovascular events over a long period of time is not clearly understood. The aim of this observational study was to estimate the ...Tieteelliset aikakauslehtiartikkelit
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Comparison of the effect of weight change, simulated computational continuous positive airway pressure treatment and positional therapy on severity of sleep apnea
Kulkas, Antti; Duce, Brett; Töyräs, Juha; Seppä, Juha; Leppänen, Timo (Wiley, 2021)Weight loss, continuous positive airway pressure (CPAP) and positional therapy (PT) are important treatments in obstructive sleep apnea (OSA). Although all of these reduce the apnea–hypopnea index (AHI) effectively, the ...Tieteelliset aikakauslehtiartikkelit
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Contrast enhanced computed tomography for real-time quantification of glycosaminoglycans in cartilage tissue engineered constructs
Garcia, João P; Longoni, Alessia; Gawlitta, Debby; Rosenberg, Antoine J W P; Grinstaff, Mark W; Töyräs, Juha; Weinans, Harrie; Creemers, Laura B; Pouran, Behdad (Elsevier BV, 2019)Tissue engineering and regenerative medicine are two therapeutic strategies to treat, and to potentially cure, diseases affecting cartilaginous tissues, such as osteoarthritis and cartilage defects. Insights into the ...Tieteelliset aikakauslehtiartikkelit
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Diagnosis of Knee Osteochondral Lesions With Ultrasound
Penttilä, Pekko; Liukkonen, Jukka; Joukainen, Antti; Virén, Tuomas; Jurvelin, Jukka S; Töyräs, Juha; Kröger, Heikki (Elsevier BV, 2015)Evaluation of articular cartilage and subchondral bone is essential in the diagnosis of joint diseases and injuries. Interobserver and intraobserver reproducibilities of arthroscopic grading are only poor to moderate. Thus, ...info:eu-repo/semantics/article
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Discrete element and finite element methods provide similar estimations for hip joint contact mechanics during walking gait
Li, Mao; Venäläinen, Mikko S; Chandra, Shekhar S; Patel, Rushabh; Fripp, Jurgen; Engstrom, Craig; Korhonen, Rami K; Töyräs, Juha; Crozier, Stuart (Elsevier BV, 2020)Finite element analysis (FEA) provides a powerful approach for estimating the in-vivo loading characteristics of the hip joint during various locomotory and functional activities. However, time-consuming procedures, such ...Tieteelliset aikakauslehtiartikkelit
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Dual Contrast in Computed Tomography Allows Earlier Characterization of Articular Cartilage over Single Contrast
Bhattarai, Abhisek; Pouran, Behdad; Mäkelä, Janne T A; Shaikh, Rubina; Honkanen, Miitu K M; Prakash, Mithilesh; Kröger, Heikki; Grinstaff, Mark W; Weinans, Harrie; Jurvelin, Jukka S; Töyräs, Juha (Wiley, 2020)Cationic computed tomography contrast agents are more sensitive for detecting cartilage degeneration than anionic or non‐ionic agents. However, osteoarthritis‐related loss of proteoglycans and increase in water content ...Tieteelliset aikakauslehtiartikkelit
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Dual‐contrast micro‐CT enables cartilage lesion detection and tissue condition evaluation ex vivo
Honkanen, Miitu KM; Mohammadi, Ali; te Moller, Nikae CR; Ebrahimi, Mohammadhossein; Xu, Wujun; Plomp, Saskia; Pouran, Behdad; Lehto, Vesa-Pekka; Brommer, Harold; van Weeren, P René; Korhonen, Rami K; Töyräs, Juha; Mäkelä, Janne TA (John Wiley & Sons Ltd, 2022)Background Post-traumatic osteoarthritis is a frequent joint disease in the horse. Currently, equine medicine lacks effective methods to diagnose the severity of chondral defects after an injury. Objectives To investigate ...
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Effects of Human Articular Cartilage Constituents on Simultaneous Diffusion of Cationic and Non-ionic Contrast Agents
Bhattarai, Abhisek; Mäkelä, Janne T A; Pouran, Behdad; Kröger, Heikki; Weinans, Harrie; Grinstaff, Mark W; Töyräs, Juha; Turunen, Mikael J (Wiley, 2021)Contrast‐enhanced computed tomography is an emerging diagnostic technique for osteoarthritis. However, the effects of increased water content, as well as decreased collagen and proteoglycan concentrations due to cartilage ...Tieteelliset aikakauslehtiartikkelit
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Estimating daytime sleepiness with previous night EEG, EOG and EMG spectrograms in patients with suspected sleep apnea using a convolutional neural network
Nikkonen, Sami; Korkalainen, Henri; Kainulainen, Samu; Myllymaa, Sami; Leino, Akseli; Kalevo, Laura; Oksenberg, Arie; Leppänen, Timo; Töyräs, Juha (Oxford University Press (OUP), 2020)A common symptom of obstructive sleep apnea (OSA) is excessive daytime sleepiness (EDS). The gold standard test for EDS is the multiple sleep latency test (MSLT). However, due to its high cost, MSLT is not routinely conducted ...Tieteelliset aikakauslehtiartikkelit
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Estimating Mechanical Properties of Bovine Knee Ligaments and Tendons with Near Infrared Spectroscopy
Torniainen, Jari E; Ristaniemi, Aapo; Stenroth, Lauri; Töyräs, Juha (The Optical Society, 2018)In this study, mechanical properties of bovine knee ligament and tendon samples were estimated using near infrared spectroscopy (NIRS). Properties related to sample stress-relaxation characteristics were found to be suitable ...other
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Gamma Power of Electroencephalogram Arousal is Modulated by Respiratory Event Type and Severity in Obstructive Sleep Apnea
Pitkanen, Henna; Duce, Brett; Leppänen, Timo; Kainulainen, Samu; Kulkas, Antti; Myllymaa, Sami; Töyräs, Juha; Korkalainen, Henri (IEEE, 2022)Objective: We aimed to investigate the differences in electroencephalogram (EEG) gamma power (30–40 Hz) of respiratory arousals between varying types and severities of respiratory events, and in different sleep stages. ...
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Increased nocturnal arterial pulsation frequencies of obstructive sleep apnoea patients is associated with an increased number of lapses in a psychomotor vigilance task
Kainulainen, Samu; Duce, Brett; Korkalainen, Henri; Leino, Akseli; Huttunen, Riku; Kalevo, Laura; Arnardottir, Erna S; Kulkas, Antti; Myllymaa, Sami; Töyräs, Juha; Leppänen, Timo (European Respiratory Society (ERS), 2020)Objectives Besides hypoxaemia severity, heart rate variability has been linked to cognitive decline in obstructive sleep apnoea (OSA) patients. Thus, our aim was to examine whether the frequency domain features of a ...Tieteelliset aikakauslehtiartikkelit
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Longer apneas and hypopneas are associated with greater ultra-short-term HRV in obstructive sleep apnea
Hietakoste, Salla; Korkalainen, Henri; Kainulainen, Samu; Sillanmäki, Saara; Nikkonen, Sami; Myllymaa, Sami; Duce, Brett; Töyräs, Juha; Leppänen, Timo (Springer Science and Business Media LLC, 2020)Low long-term heart rate variability (HRV), often observed in obstructive sleep apnea (OSA) patients, is a known risk factor for cardiovascular diseases. However, it is unclear how the type or duration of individual ...Tieteelliset aikakauslehtiartikkelit
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Longer duration electroencephalogram arousals have a better relationship with impaired vigilance and health status in obstructive sleep apnoea
Duce, Brett; Kulkas, Antti; Töyräs, Juha; Terrill, Philip; Hukins, Craig (Springer Science and Business Media LLC, 2020)Purpose Obstructive sleep apnoea (OSA) is a prevalent sleep disorder with significant health consequences. Sleep fragmentation is a feature of OSA and is often determined by the arousal index (ArI), a metric based on the ...Tieteelliset aikakauslehtiartikkelit
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Machine learning augmented near-infrared spectroscopy: In vivo follow-up of cartilage defects
Sarin, Jaakko K; Te Moller, Nikae Cr; Mohammadi, Ali; Prakash, Mithilesh; Torniainen, Jari; Brommer, Harold; Nippolainen, Ervin; Shaikh, Rubina; Mäkelä, Janne Ta; Korhonen, Rami K; René van Weeren, P; Afara, Isaac O; Töyräs, Juha (Elsevier BV, 2021)Objective To assess the potential of near-infrared spectroscopy (NIRS) for in vivo arthroscopic monitoring of cartilage defects. Method Sharp and blunt cartilage grooves were induced in the radiocarpal and intercarpal ...Tieteelliset aikakauslehtiartikkelit
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Method for Segmentation of Knee Articular Cartilages Based on Contrast-Enhanced CT Images
Myller, Katariina AH; Honkanen, Juuso TJ; Jurvelin, Jukka S; Saarakkala, Simo; Töyräs, Juha; Väänänen, Sami P (Springer Nature America, Inc, 2018)Segmentation of contrast-enhanced computed tomography (CECT) images enables quantitative evaluation of morphology of articular cartilage as well as the significance of the lesions. Unfortunately, automatic segmentation ...Tieteelliset aikakauslehtiartikkelit
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Near Infrared Spectroscopy Enables Differentiation of Mechanically and Enzymatically Induced Cartilage Injuries
Nippolainen, Ervin; Shaikh, Rubina; Virtanen, Vesa; Rieppo, Lassi; Saarakkala, Simo; Töyräs, Juha; Afara, Isaac (Springer Science and Business Media LLC, 2020)This study evaluates the feasibility of near infrared (NIR) spectroscopy to distinguish between different cartilage injury types associated with post-traumatic osteoarthritis and idiopathic osteoarthritis (OA) induced by ...Tieteelliset aikakauslehtiartikkelit
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Power spectral densities of nocturnal pulse oximetry signals differ in OSA patients with and without daytime sleepiness
Kainulainen, Samu; Töyräs, Juha; Oksenberg, Arie; Korkalainen, Henri; Afara, Isaac O; Leino, Akseli; Kalevo, Laura; Nikkonen, Sami; Gadoth, Natan; Kulkas, Antti; Myllymaa, Sami; Leppänen, Timo (Elsevier BV, 2020)Background As nocturnal hypoxemia and heart rate variability are associated with excessive daytime sleepiness (EDS) related to OSA, we hypothesize that the power spectral densities (PSD) of nocturnal pulse oximetry signals ...Tieteelliset aikakauslehtiartikkelit
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Quantitative dual contrast photon-counting computed tomography for assessment of articular cartilage health
Paakkari, Petri; Inkinen, Satu I; Honkanen, Miitu KM; Prakash, Mithilesh; Shaikh, Rubina; Nieminen, Miika T; Grinstaff, Mark W; Mäkelä, Janne TA; Töyräs, Juha; Honkanen, Juuso TJ (Springer Science and Business Media LLC, 2021)Photon-counting detector computed tomography (PCD-CT) is a modern spectral imaging technique utilizing photon-counting detectors (PCDs). PCDs detect individual photons and classify them into fixed energy bins, thus enabling ...Tieteelliset aikakauslehtiartikkelit