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1.
  • Hafström, L., et al. (författare)
  • An exploration of Swedish companies' offshoring of R&D activities to China
  • 2010
  • Ingår i: 5th IEEE International Conference on Management of Innovation and Technology, ICMIT2010, Singapore; 2 June 2010 through 5 June 2010. - 9781424465675 ; , s. 306-311
  • Konferensbidrag (refereegranskat)abstract
    • A trend among manufacturing companies is offshoring of R & D. The aim of this study is to investigate Swedish companies' offshoring of R & D activities to China, utilizing both a survey and explorative case studies. The survey results show that 9% of the companies have offshored R & D to China, that performance in China is satisfactory, primarily in terms of costs, and that there is a need for strong integration mechanisms to handle coordination and information sharing. Based on the case studies, a categorization of firms offshoring R & D into Market- & Talent-driven firms and Low-cost & Supplydriven firms is proposed, as these have different challenges and require different managerial solutions. Finally, a dilemma concerning information sharing and innovation is identified and discussed. © 2010 IEEE.
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2.
  • Fransson, Per-Anders, et al. (författare)
  • Analysis of Postural Control Adaptation during Galvanic and Vibratory Stimulation
  • 2001
  • Ingår i: Proc. 23rd Annual EMBS International Conference (EMBC2001). ; , s. 1170-1173
  • Konferensbidrag (refereegranskat)abstract
    • The objective for this study was to investigate whether the postural control adaptation during galvanic stimulation of the vestibular nerve were similar to that found during vibration stimulation to the calf muscles. A method for adaptation analysis was used to analyze the evoked changes of posture, stimulus responses and the motion dynamics. The adaptive adjustments of postural control were similar during galvanic and vibratory stimulation, which suggests that the adaptation operate in the same way independent of the receptor systems affected by the disturbance. There was however a difference in the dynamic feedback properties of the measured responses.
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3.
  • Fransson, Per-Anders, et al. (författare)
  • Analysis of Short- and Long-Term Effects of Adaptation in Human Postural Control
  • 2002
  • Ingår i: Biological Cybernetics. - : Springer Science and Business Media LLC. - 1432-0770 .- 0340-1200. ; 86:5, s. 355-365
  • Tidskriftsartikel (refereegranskat)abstract
    • The short-term (i.e., days) and long-term (i.e., months) effects of adaptation to posturography examinations were investigated in 12 normal subjects who were repeatedly examined for five consecutive days and again after 90 days. The examinations were conducted both with eyes open and closed, and the perturbations were evoked by a pseudorandomly applied vibration stimulation to the calf muscles. The evoked anteroposterior responses were analyzed with a method considering adaptation in the slow changes in posture and in the stimulus-response relationship. Repetition of examinations on a daily basis revealed a gradual improvement of postural-control performance. The body sway induced by the stimulation was significantly reduced and the dynamical properties changed. Most of the improvements remained after 90 days, but some parameters such as the complexity of the control system used were increased to the initial level. The results confirm previous observations that postural control contains several partially independent adaptive processes, observed in terms of alteration of posture and as a progressive reduction of body sway induced by stimulation. The method used for the adaptation analysis in this study could be applied to analyze biological systems with multiple individual adaptive processes with different time courses or characteristics, or where the adaptation processes are related to multiple internal or external factors.
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4.
  • Fransson, Per-Anders, et al. (författare)
  • Balance Control and Adaptation during Vibratory Perturbations in Middle-Aged and Elderly Humans.
  • 2004
  • Ingår i: European Journal of Applied Physiology. - : Springer Science and Business Media LLC. - 1439-6327 .- 1439-6319. ; 91:5-6, s. 595-603
  • Tidskriftsartikel (refereegranskat)abstract
    • The objective was to investigate if healthy elderly people respond and adapt differently to postural disturbances compared to middle-aged people. Thirty middle-aged (mean age 37.8 years, range 24–56 years) and forty healthy elderly subjects (mean age 74.6 years, range 66–88 years) were tested with posturography. Body sway was evoked by applying pseudorandom vibratory stimulation to the belly of the gastrocnemius muscles of both legs simultaneously. The tests were performed both with eyes open and eyes closed. The anteroposterior body sway was measured with a force platform and analyzed with a method that considers the adaptive changes of posture and stimulation responses. The results showed that middle-aged people generally used a different postural control strategy as compared to the elderly. The elderly responded more rapidly to vibratory perturbation, used more high-frequency (>0.1 Hz) motions and the motion dynamics had a higher degree of complexity. Moreover, the elderly had diminished ability to use visual information to improve balance control. Altogether, despite having an effective postural control adaptation similar to that of middle-aged people, the elderly had more difficultly in withstanding balance perturbations. These findings suggest that the balance control deterioration associated with aging cannot be fully compensated for by postural control adaptation.
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5.
  • Fransson, Per-Anders, et al. (författare)
  • Methods for Evaluation of Postural Control Adaptation
  • 2000
  • Ingår i: Gait & Posture. - 1879-2219. ; 12:1, s. 14-24
  • Tidskriftsartikel (refereegranskat)abstract
    • New methods were developed to determine the dynamic changes of postural control during the initial exposure to large perturbances of stance. The adjustments of postural control over time in measured anteroposterior torque, were investigated in ten normal subjects. Perturbations of stance were evoked by two high intensity vibrators applying pseudorandom stimulation either to the calf muscles or the paravertebral muscles of the neck. The new methods use a system identification approach, which distinguishes between feedback control, adaptation of postural responses and adaptation to stimulus. This approach makes it possible to quantify motion dynamics and complexity, stimulus impact and adjustments of postural control. Quantification of the different adaptive responses could be useful for diagnostic purposes, in evaluating treatment efficacy and patient progress in rehabilitation programs.
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6.
  • Fransson, Per-Anders, et al. (författare)
  • Postural Control Adaptation during Galvanic Vestibular and Vibratory Proprioceptive Stimulation
  • 2003
  • Ingår i: IEEE Transactions on Biomedical Engineering. - 1558-2531. ; 50:12, s. 1310-1319
  • Tidskriftsartikel (refereegranskat)abstract
    • he objective for this study was to investigate whether the adaptation of postural control was similar during galvanic vestibular stimulation and during vibratory proprioceptivestimulation of the calf muscles. Healthy subjects were tested during erect stance with eyes open or closed. An analysis method designed to consider the adaptive adjustments was used to evaluate the motion dynamics and the evoked changes of posture and stimulation response.Galvanic vestibular stimulation induced primarily lateral body movements and vibratory proprioceptive stimulation induced anteroposterior movements. The lateral body sway generated by the galvanic stimulation was proportionally smaller and contained more high-frequency movements (0.1 Hz) than the anteroposterior body sway induced by the vibratory stimulation. The adaptive adjustments of the body sway to the stimulation had similar time course and magnitude during galvanic and vibratory stimulation. The perturbations induced by stimulation were gradually reduced within the same time range (15–20 s) and both kinds of stimulation induced a body leaning whose direction was dependent on stimulus. The similarities in the adjustmentpatterns suggest that postural control operates in the same way independent of the receptor systems affected by the disturbance and irrespective of whether the motion responses were induced in a lateral or anteroposterior direction.
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7.
  • Greiff, Lennart, et al. (författare)
  • Non-radical primary diagnostic biopsies affect survival in cutaneous head and neck melanoma
  • 2021
  • Ingår i: Acta Oto-Laryngologica. - : Informa UK Limited. - 0001-6489 .- 1651-2251. ; 141:3, s. 309-319
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: It is unclear if a non-radical diagnostic biopsy entails a higher risk for metastasis and poorer survival for patients with cutaneous head and neck melanoma (cHNM). Aims/objectives: To assess whether or not initial diagnostic biopsy modality and radicality (clear, positive, or narrow histopathological margins) influence recurrence and survival in patients with cHNM. Materials and methods: Histopathological radicality of initial diagnostic biopsies and outcome for 368 consecutive cHNM patients, clinically asymptomatic of metastatic disease and referred to a tertiary care academic center for sentinel lymph node staging from 2004 through 2018, were retrospectively analyzed. Results: Patients with positive (n = 133) or narrow (0.1–0.5 mm) (n = 34) histopathological margins had significantly worse loco-regional (p=.004) and distant control (p=.004) as well as lower overall (p=.017) and melanoma specific (p=.0002) survival than 201 patients with clear margins. Multivariate analysis indicated positive or narrow histopathological margins as independent negative prognostic factors for melanoma specific survival (HR 2.16, p=.015), together with deeper Breslow (HR 1.17, p=.00001) and ulceration (HR 2.49, p=.003). Conclusions and significance: Non-radical primary diagnostic biopsies increase the risk for metastatic disease and impair survival in cHNM. Accordingly, radical melanoma diagnostic procedures should be encouraged in the head and neck region when possible.
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8.
  • Hafström, Anna, et al. (författare)
  • Acute alcohol intoxication impairs segmental body alignment in upright standing.
  • 2014
  • Ingår i: Journal of Vestibular Research. - 1878-6464. ; 24:4, s. 297-304
  • Tidskriftsartikel (refereegranskat)abstract
    • Balance control when standing upright is a complex process requiring input from several partly independent mechanisms such as coordination, feedback and feedforward control, and adaptation. Acute alcohol intoxication from ethanol is recognized as a major contributor to accidental falls requiring medical care. This study aimed to investigate if intoxication at 0.06 and 0.10% blood alcohol concentration affected body alignment. Mean angular positions of the head, shoulder, hip, and knee were measured with 3D-motion analysis and compared with the ankle position in 25 healthy adults during standing with or without perturbations, and with eyes open or closed. Alcohol intoxication had significant effects on body alignment during perturbed and unperturbed stance, and on adaptation to perturbations. It induced a significantly more posterior alignment of the knees and shoulders, and a tendency for a more posterior and left deviated head alignment in perturbed stance than when sober. The impact of alcohol intoxication was most apparent on the knee alignment, where availability of visual information deteriorated the adaptation to perturbations. Thus, acute alcohol intoxication resulted in inadequate balance control strategies with increased postural rigidity and impaired adaptation to perturbations. These factors probably contribute to the increased risk of falling when intoxicated with alcohol.
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9.
  • Hafström, Anna, et al. (författare)
  • Effectuation of adaptive stability and postural alignment strategies are decreased by alcohol intoxication.
  • 2014
  • Ingår i: Human Movement Science. - : Elsevier BV. - 1872-7646 .- 0167-9457. ; 35:Apr 29, s. 30-49
  • Tidskriftsartikel (refereegranskat)abstract
    • Human stability control is a complex process comprising contributions from several partly independent mechanisms such as coordination, feedback and feed-forward control, and adaptation. Acute alcohol intoxication impairs these functions and is recognized as a major contributor to fall traumas. The study aimed to investigate how alcohol intoxication at .06% and .10% blood alcohol concentration (BAC) affected the movement spans and control of posture alignment. The angular positions of the head, shoulder, hip and knees relative to the ankles were measured with a 3D motion analysis system in 25 healthy adults during standing with eyes open or closed and with or without vibratory balance perturbations. Alcohol intoxication significantly increased the movement spans of the head, shoulders, hip and knees in anteroposterior and lateral directions during quiet stance (p⩽.047 and p⩽.003) and balance perturbations (p<.001, both directions). Alcohol intoxication also decreased the ability to reduce the movement spans through adaptation in both anteroposterior (p⩽.011) and lateral (p⩽.004) directions. When sober and submitted to balance perturbations, the subjects aligned the head, shoulders, hip and knees more forward relative to the ankle joint (p<.001), hence adopting a more resilient posture increasing the safety margin for backward falls. Alcohol intoxication significantly delayed this forward realignment (p⩽.022). Alcohol intoxication did not cause any significant posture realignment in the lateral direction. Thus, initiation of adaptive posture realignments to alcohol or other disruptions might be context dependent and associated with reaching a certain level of stability threats.
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  • Hafström, Anna, et al. (författare)
  • Improved Balance Confidence and Stability for Elderly After 6 Weeks of a Multimodal Self-Administered Balance-Enhancing Exercise Program : A Randomized Single Arm Crossover Study
  • 2016
  • Ingår i: Gerontology and Geriatric Medicine. - : SAGE Publications. - 2333-7214. ; 2, s. 1-13
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective: To develop and assess the efficacy of a multimodal balance-enhancing exercise program (BEEP) designed to be regularly self-administered by community-dwelling elderly. The program aims to promote sensory reweighting, facilitate motor control, improve gaze stabilization, and stimulate continuous improvement by being constantly challenging. Method: Forty participants aged 60 to 80 years performed 6 weeks of BEEP training, on average for 16 min four times weekly, in a randomized one-arm crossover design. Results: One-leg standing time improved 32% with eyes open (EO), 206% with eyes closed (EC) on solid surface, and 54% EO on compliant surface (p < .001). Posturography confirmed balance improvements when perturbed on solid and compliant surfaces with EO and EC (p ≤ .033). Walking, step stool, and Timed Up and Go speeds increased (p ≤ .001), as did scores in Berg Balance and balance confidence scales (p ≤ .018). Discussion: Multimodal balance exercises offer an efficient, cost-effective way to improve balance control and confidence in elderly.
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  • Hafström, Anna, et al. (författare)
  • Increased visual dependence and otolith dysfunction with alcohol intoxication
  • 2007
  • Ingår i: NeuroReport. - 1473-558X. ; 18:4, s. 391-394
  • Tidskriftsartikel (refereegranskat)abstract
    • dAlcohol intoxication affects the vestibular system and balance control in many ways. We have investigated how acute, moderate (blood alcohol concentrations of 0.06 +/- 0.01%), and high (0.10 +0.02%) alcohol intoxication affects the ability to perceive the visual horizontal and vertical and the visual field dependence measured with the rod and frame tests in 24 healthy participants. Alcohol ingestion impaired the ability to use gravitational vestibular cues when determining the visual vertical and horizontal, and caused increased visual field dependence. With conflicting gravitational and visual information, alcohol seems to promote a reweighting in balance control from a vestibular to a more visual dependency. Furthermore, the results indicate that alcohol intoxication at these levels start instigating a decompensation of minute subdinical vestibular asymmetries.
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14.
  • Hafström, Anna, et al. (författare)
  • Outcome for sinonasal malignancies : a population-based survey
  • 2022
  • Ingår i: European Archives of Oto-Rhino-Laryngology. - : Springer Science and Business Media LLC. - 0937-4477 .- 1434-4726. ; 279:5, s. 2611-2622
  • Tidskriftsartikel (refereegranskat)abstract
    • Purpose: Sinonasal malignancies (SNM) represent a rare and complex group of cancers that includes a wide range of histopathological subtypes. Data from population-based cohorts are scarce but warranted as a basis for randomized controlled treatment trials (RCTs). Our aim was to assess overall and histology subset-specific outcomes for SNM patients treated at a tertiary referral centre. Methods: A retrospective, population-based, consecutive cohort of patients with SNMs diagnosed from 2001 through 2019 was examined. Outcome was analysed in relation to age, gender, site, stage, histopathology, and treatment. Results: Two-hundred and twenty-six patients were identified, whereof 61% presented with stage IV disease. 80% completed treatment with curative intent, which comprised surgery with neoadjuvant (29%) or adjuvant (37%) radiotherapy, monotherapy with surgery (22%), definitive chemoradiotherapy (7%), or radiotherapy (5%). Median follow-up was 106 months. The 5- and 10-year overall survival rates were 57% and 35%, respectively. Median overall survival was 76 months (esthesioneuroblastoma: 147 months; adenocarcinoma: 117; salivary carcinoma: 88; mucosal melanoma: 69; squamous cell carcinoma: 51, undifferentiated carcinoma: 42; neuroendocrine carcinoma: 9; and NUT-carcinoma 5). The 5- and 10-year disease-free survival rates were 63% and 54%, respectively, and disease-specific survival 83% and 66%. Increasing age, stage IVB, melanoma histopathology, and treatment with definitive chemoradiotherapy emerged as significant independent prognostic risk factors for disease-specific mortality (p ≤ 0.001). Conclusion: The results indicate a seemingly good outcome in comparison to previous reports, particularly for mucosal melanoma, adenocarcinoma, and undifferentiated carcinoma. The study provides additional background for future RCTs focusing on histology subset-specific treatment for SNM.
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15.
  • Hafström, Anna, et al. (författare)
  • Patients with cutaneous head and neck melanoma, particularly elderly with more advanced primary tumors, seem to benefit from initial CT staging before considering a sentinel lymph node biopsy
  • 2020
  • Ingår i: Acta Oto-Laryngologica. - : Informa UK Limited. - 0001-6489 .- 1651-2251. ; 140:9, s. 795-802
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: The role of CT scanning at the time of diagnosis for patients with primary cutaneous head and neck melanoma (cHNM) clinically asymptomatic for metastatic disease remains unclear. Aim: To determine the positive yield of initial CT scanning before considering sentinel lymph node biopsy (SLNB) staging. Materials and methods: A retrospective review was performed on 170 consecutive patients with cHNM referred to a tertiary head and neck academic center for SLNBs from 2014 through 2018. Results: Initial CTs identified occult melanoma metastases in 7.1% and other advanced malignancies in 4.7%. The overall CT yield for patients >65 years (n = 115) was 13.9%, and 5.5% for patients <65 (only occult melanoma metastases). The SLNB yield did not differ between older (11.5%) and younger patients (10.2%). Patients with more advanced primary tumors were upstaged more often by both staging procedures. Multivariate analysis indicated a true-positive CT finding as the strongest prognostic factor for OS (p<.001). Conclusions and significance: The CT yield was >11% and higher for older than for younger patients. The findings suggest that CT imaging may be considered before SLNB staging, potentially identifying metastatic melanoma disease as well as other occult malignancies, enabling especially older patients to bypass the SLNB procedure.
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16.
  • Hafström, Anna (författare)
  • Perceived and functional balance control is negatively affected by diminished touch and vibration sensitivity in relatively healthy older adults and elderly
  • 2018
  • Ingår i: Gerontology and Geriatric Medicine. - : SAGE Publications. - 2333-7214. ; 4, s. 1-10
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Severe diminished foot somatosensation, for example, caused by neuropathies and advanced aging, contributes to balance deficits and increased fall risk. However, little is known about somatosensory impairment and functional and subjective balance problems in relatively healthy elderly. Method: Vibration perception thresholds (VPTs) were assessed with a biothesiometer and tactile pressure sensation thresholds (TPSTs) with 20 monofilaments in 34 relatively healthy community-dwelling older adults (M = 69.4 years). Balance was evaluated with functional balance tests and questionnaires. A stepwise regression analysis was performed to determine the extent to which VPTs, TPSTs, and age could explain balance impairments. Results: High VPTs had negative effects on Berg Balance Scale and Dizziness Handicap Inventory scores (p ≤ .011), as did high TPSTs on walking speed and Figure-8 test (p ≤ .001). With visual information available, one-leg standing time (OLST) was significantly affected by ipsilateral VPTs on solid and TPSTs on compliant surface (p ≤ .002). Without visual information, age was the only factor with a main effect on OLST (p < .001). Age had no significant correlations with TPSTs or VPTs. Discussion: Somatosensation appears to be very important for perceived as well as functional balance control in older adults. Our findings have important clinical implications when assessing balance impairment and impending fall risk.
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17.
  • Hafström, Anna, et al. (författare)
  • Predictors of survival in advanced oral cancers after salvage surgery with free tissue flap reconstruction
  • 2023
  • Ingår i: European Archives of Oto-Rhino-Laryngology. - : Springer Science and Business Media LLC. - 0937-4477 .- 1434-4726. ; 280:6, s. 2953-2964
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective: To identify prognostic factors for patients with advanced persistent, recurrent, or 2nd primary oral cavity squamous cell carcinoma (OCSCC) potentially unsuitable for salvage surgery with free tissue flap (FTF) reconstruction. Materials and methods: A population-based cohort of 83 consecutive patients with advanced OCSCC who underwent salvage surgery with FTF reconstruction at a tertiary referral centre between 1990 and 2017. Retrospective uni- and multivariable analyses were performed to identify factors affecting all-cause mortality (ACM), i.e., overall survival (OS), as well as disease-specific mortality (DSM), i.e., disease-specific survival (DSS) after salvage surgery. Results: Median disease-free interval until recurrence was 15 months with recurrent stage I/II in 31% and III/IV in 69%. Median age at salvage surgery was 67 years (range 31–87) and the median follow-up (alive patients) 126 months. At 2, 5, and 10 years after salvage surgery, respectively, DSS rates were 61%, 44%, and 37% and OS rates 52%, 30%, and 22%. Median DSS was 26 and OS 43 months. Multivariable analysis identified recurrent clinical regional (cN-plus) disease [HR 3.57; p <.001] and elevated gamma-glutamyl transferase (GGT) [HR 3.30; p =.003] as independent pre-salvage predictors for poor OS after salvage, whereas initial cN-plus [HR 2.07; p =.039] and recurrent cN-plus disease [HR 5.14; p <.001] predicted poor DSS. Among post-salvage factors, extranodal extension according to histopathology [HR ACM 6.11; HR DSM 9.99; p <.001] as well as positive [HR ACM 4.98; DSM 7.51; p < 0.001] and narrow surgical margins [HR ACM 2.12; DSM HR 2.80; p < 0.01] emerged as independent factors for poor survival. Conclusion: While salvage surgery with FTF reconstruction is the primary curative option for patients with advanced recurrent OCSCC, the present findings may help guide discussions with patients who have advanced recurrent regional disease and high GGT preoperatively, especially if there is a small chance of reaching surgical radicality.
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18.
  • Hafström, Anna, et al. (författare)
  • Sentinel lymph node biopsy staging for cutaneous malignant melanoma of the head and neck.
  • 2016
  • Ingår i: Acta Oto-Laryngologica. - : Informa UK Limited. - 1651-2251 .- 0001-6489. ; 136:3
  • Tidskriftsartikel (refereegranskat)abstract
    • Conclusion Sentinel lymph node biopsies (SLNBs) can be performed safely and with reasonable accuracy in HNM patients. The outcome provides important prognostic information concerning DFS and further treatment. However, one must recognize that SLNB is a multidisciplinary procedure with a learning curve for all. Objectives To evaluate efficacy of performing SLNBs in a series of consecutive patients with cutaneous head and neck melanoma (HNM) ≥ T1b from introduction of the procedure and 10 years onward. Method End-points comprised of SLNB outcome, disease-free survival (DFS), and overall survival (OS). Results SNs were harvested in 128 of 160 patients (median Breslow = 2.0 mm, 29% ulcerated); success rate = 80.0%, or 92.1% if excluding patients where SLNBs were omitted due to non-localization on pre-operative imaging or because of SN-location in the parotid basin. Ten patients (7.8%) had positive SLNBs and were offered early completion neck dissections. Of the 146 patients available for follow-up (median = 27 months), 15.8% had recurrent disease. The risk of a regional nodal recurrence after a negative SLNB was 7.5%. SN-negative patients had improved DFS c.f. SN-positive patients (p < 0.001). A positive SLNB was the most important prognostic predictor of decreased DFS (hazard ratio = 5.70; p < 0.005), but had no significant impact on OS.
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  • Hafström, Anna, et al. (författare)
  • Visual influence on postural control, with and without visual motion feedback.
  • 2002
  • Ingår i: Acta Oto-Laryngologica. - : Informa UK Limited. - 1651-2251 .- 0001-6489. ; 122:4, s. 392-397
  • Tidskriftsartikel (refereegranskat)abstract
    • Body sway was investigated in 20 healthy subjects to determine whether visual input must contain motion feedback information from the surroundings in order to influence postural control. Posturography was used to record body sway under the following visual conditions: eyes open with or without a restricted visual field; eyes open in ganzfield white light; eyes open in darkness with a head-fixed visual target; eyes open in darkness; and eyes closed in darkness. Stance was perturbed by means of a pseudorandomly applied vibratory stimulation to the calf muscles. Least sway was found with eyes open in an unrestricted visual field but increased in a restricted visual field. Greatest sway was found without visual motion feedback, i.e. under the following conditions: eyes closed; eyes open in darkness; eyes open in ganzfield white light; and with a head-mounted fixation point. Sway was significantly (p < 0.05) greater with eyes open in darkness compared with eyes closed during the initial 50 s with perturbations. After 150 s, sway was almost identical under the four test conditions without visual motion feedback. Standing with eyes open in darkness was initially a disadvantage compared with having the eyes closed. The postural control system may be programmed to expect visual feedback information when the eyes are open, which may delay changes in postural strategy.
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23.
  • Hafström, Anna (författare)
  • Visual influences on vestibular compensation and postural control
  • 2007
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • This thesis aimed to investigate visual-vestibular interactions in healthy subjects and in patients with a well defined unilateral vestibular lesion (vestibular schwannoma before and six months after translabyrinthine surgery). Visual information is particularly important for balance control during perturbed stance. The physical act of having the eyes open or closed affects motion strategy in postural control. Standing with eyes open in darkness during balance perturbations is initially of disadvantage compared to standing with eyes closed. The postural control system appears to expect visual feedback information when eyes are open, which delays a re-weighting to vestibular and proprioceptive information. A pathologic deviation of the subjective visual horizontal (SVH) and vertical (SVV) toward the lesioned side is still present six months after unilateral vestibular deafferentation. There is great SVH and SVV variability between patients which proposes an idiosyncrasy in the compensation of graviceptive vestibular tone imbalance. Postural sway is not related to the deviation of the SVH and SVV which indicates that utriculo-ocular compensation is not related to postural compensation. Patients with a unilateral vestibular schwannoma are not more visually field dependent than healthy subjects are, but have an increased ipsilesional deviation in the rod and frame test. This suggests asymmetric visual field dependence, and that the rod and frame test can reveal a hidden vestibular imbalance. Older patients with a vestibular schwannoma have increased visual dependency and decreased compensation of the SVH and SVV compared to younger patients. Alcohol intoxication impairs the ability to use gravitational vestibular cues in SVH and SVV tests, and increases visual field dependence. Visual dependence and visual-vestibular interactions are important factors to consider when investigating and rehabilitating patients with balance disorders. With conflicting gravitational and visual information a re-weighting from a vestibular to a more visual dependency in balance control might increase the risk of misinterpreting the visual information and thus increase the risk of accidents. It is important with good lighting conditions to provide patients with adequate sway referencing visual information.
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24.
  • Helkkula, Teo, et al. (författare)
  • BioMEL : a translational research biobank of melanocytic lesions and melanoma
  • 2024
  • Ingår i: BMJ Open. - 2044-6055. ; 14:2
  • Tidskriftsartikel (refereegranskat)abstract
    • Introduction Diagnosing invasive cutaneous melanoma (CM) can be challenging due to subjectivity in distinguishing equivocal nevi, melanoma in situ and thin CMs. The underlying molecular mechanisms of progression from nevus to melanoma must be better understood. Identifying biomarkers for treatment response, diagnostics and prognostics is crucial. Using biomedical data from biobanks and population-based healthcare data, translational research can improve patient care by implementing evidence-based findings. The BioMEL biobank is a prospective, multicentre, large-scale biomedical database on equivocal nevi and all stages of primary melanoma to metastases. Its purpose is to serve as a translational resource, enabling researchers to uncover objective molecular, genotypic, phenotypic and structural differences in nevi and all stages of melanoma. The main objective is to leverage BioMEL to significantly improve diagnostics, prognostics and therapy outcomes of patients with melanoma. Methods and analysis The BioMEL biobank contains biological samples, epidemiological information and medical data from adult patients who receive routine care for melanoma. BioMEL is focused on primary and metastatic melanoma, but equivocal pigmented lesions such as clinically atypical nevi and melanoma in situ are also included. BioMEL data are gathered by questionnaires, blood sampling, tumour imaging, tissue sampling, medical records and histopathological reports. Ethics and dissemination The BioMEL biobank project is approved by the national Swedish Ethical Review Authority (Dnr. 2013/101, 2013/339, 2020/00469, 2021/01432 and 2022/02421-02). The datasets generated are not publicly available due to regulations related to the ethical review authority. Trial registration number NCT05446155.
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  • Ledin, Torbjörn, 1962-, et al. (författare)
  • Influence of neck proprioception on vibration-induced postural sway
  • 2003
  • Ingår i: Acta Oto-Laryngologica. - : Informa UK Limited. - 1651-2251 .- 0001-6489. ; 123:5, s. 594-599
  • Tidskriftsartikel (refereegranskat)abstract
    • Objective-Several reports have shown that the direction of the postural responses induced by vestibular stimulation is affected by the positions of the neck and torso. The aim of this study was to investigate whether the postural responses to vibratory proprioceptive stimulation of the calf muscles are affected by the position of the head and thus by proprioceptive and vestibular information from the neck and head. Material and Methods-Ten normal subjects were exposed to vibratory proprioceptive stimulation of the calf muscles when the head was maintained in five different positions: in a neutral position facing forwards, with the head turned to the right or left sides or with the head tilted backwards or forwards. Body movements were evaluated by analyzing the anteroposterior and lateral torques induced towards the supporting surface. Results-The analysis showed that only the anteroposterior body sway was significantly affected by the position of the head. The anteroposterior postural responses were primarily increased during the tests with the head tilted backwards or forwards, whereas the postural responses were unaffected by head torsion towards the sides. The lateral responses were primarily affected by vision and not by the position of the head. Conclusions-The findings suggest that the responses evoked by vibratory proprioceptive stimulation of the calf muscles may be affected by different mechanisms, either by purely proprioceptive information or by an interaction between proprioceptive and vestibular information. Moreover, the increasing difference between the test conditions over time suggests that fatigue of the neck muscles may be one of the factors affecting the responses induced by the perturbations.
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  • Malmström, Eva Maj, et al. (författare)
  • Co-morbidities to Vestibular Impairments—Some Concomitant Disorders in Young and Older Adults
  • 2021
  • Ingår i: Frontiers in Neurology. - : Frontiers Media SA. - 1664-2295. ; 11
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: Dizziness and pain are common complaints that often appear concomitantly, with or without a causal relationship. However, these symptoms might maintain and exacerbate each other and other co-morbidities. Therefore, adequate rehabilitation may have to include an expanded focus on other deficits and preconditions, especially in older adults and in patients. Objective: To understand how frequently vestibular dysfunction coincided with medical conditions and aging, we studied two categories: Study 1: patients referred to a vestibular unit and Study 2: senior members in a fitness association. Method: Study 1: 49 patients [34 females/15 males; mean age 52 years (SEM 2.0)] seeking health care for balance disorders and vestibular deficits were asked in questionnaires about their perception of dizziness and pain, and emotional and functional strains. Study 2: 101 senior members in a fitness association [91 females/10 males; mean age 75 years (SEM 0.6)], were assessed for vestibular and balance deficits and for any co-morbidities. The participants were monitored for falls for 12 months after the initial assessments. Result: Study 1: Co-morbidity often existed between dizziness and pain (65%). The patients reported high emotional and functional strain related to their dizziness and pain. Patients older than 60 years reported longer durations of pain (p ≤ 0.028) but less emotional strain (p = 0.036), compared to younger patients. Study 2: 84% of the participants had a vestibular impairment, often without noticing any symptoms. Furthermore, 40% reported cardiovascular illnesses, 12% musculoskeletal disorders, and 63% reported other medical conditions. Forty-two percent experienced falls within 1 year after the initial assessments (thereof 42% in the group with vestibular deficits and 38% in the group without vestibular deficits). Conclusion: To enhance and preserve postural control, both in patients with vestibular deficits and in older adults, we suggest an expanded clinical perspective. Hence, we recommend detailed examinations of the vestibular system but simultaneously probing for possible co-morbidities. Since aging often entails deterioration of multimodal processes related to maintained mobility and postural stability, our results add focus on the importance of addressing balance disorders together with additional medical conditions.
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29.
  • Mobargha, Nathalie, et al. (författare)
  • Scapular osseous free flap in head and neck reconstruction : An assessment of the postoperative function of the donor site
  • 2022
  • Ingår i: Journal of Plastic, Reconstructive and Aesthetic Surgery. - : Elsevier BV. - 1748-6815. ; 75:2, s. 753-760
  • Tidskriftsartikel (refereegranskat)abstract
    • Background: The scapular osseous free flap (SOFF) has become an important reconstructive option for complex head and neck defects. Postoperative donor site function is, however, an important consideration. The objective of this study was to prospectively investigate SOFF donor site morbidity and to relate the findings to hand dominance and neck dissection. Methods: Objective assessment included bilateral measurement of shoulder, elbow, and hand range of motion (ROM), hand strength, and distal nerve function in consecutive patients with head and neck cancer SOFF reconstruction at a tertiary referral center in Sweden between 2016 and 2019. The subjective function was assessed by the Disability of the Arm, Shoulder and Hand (DASH) questionnaire. Results: Sixteen of 20 consecutive patients were evaluated (median follow-up 10 months [range 3–17]). Significant side differences in shoulder range of motion (ROM) (flexion, abduction, external and internal rotation) were observed for patients where the SOFF had been harvested from the same side as their dominant hand (n = 9; Ps ≤ 0.04). For patients where the SOFF was harvested from the non-dominant hand side, no significant shoulder ROM side differences were observed (n = 7; Ps ≥ 0.08). There were significant side differences in shoulder ROM for patients who underwent neck dissections (n = 12; Ps ≤ 0.03), not for the other four patients. Patients reported low but varying DASH scores (median 2.5, range 0–57). Conclusion: Postoperative donor site morbidity seems to be quite acceptable after SOFF surgery. The results indicate possible benefits of choosing the non-dominant hand side for the SOFF and that a neck dissection affects postoperative shoulder outcome. Further studies are however needed.
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30.
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31.
  • Silfverschiöld, Maria, et al. (författare)
  • Cost of Illness of Head and Neck Cancer in Sweden
  • Ingår i: Value in Health. - 1098-3015.
  • Tidskriftsartikel (refereegranskat)abstract
    • OBJECTIVES: Head and neck cancer (HNC) is the sixth most common cancer worldwide. The condition and its treatment often lead to marked morbidities and, for some patients, premature death. Inferentially, HNC imposes a significant economic burden on society. This study aims to provide a comprehensive and detailed estimation of the cost of illness of HNC for Sweden in 2019.METHODS: This is a prevalence-based cost of illness study. Resource utilization and related costs are quantified using national registry data. A societal perspective is applied, including (1) direct costs for healthcare utilization, (2) costs for informal care from family and friends, and (3) costs for productivity loss due to morbidity and premature death. The human capital approach is used when estimating productivity losses.RESULTS: The societal cost of HNC for Sweden in 2019 was estimated at €92 million, of which the direct costs, costs for informal care, and costs for productivity loss represented 34%, 2%, and 64%, respectively. Oral cavity cancer was the costliest HNC, followed by oropharyngeal cancer, whereas nasopharyngeal cancer was the costliest per person. The cost of premature mortality comprised 60% of the total cost of productivity loss. Males accounted for 65% of direct costs and 67% of costs for productivity loss.CONCLUSIONS: The societal cost of HNC is substantial and constitutes a considerable burden to Swedish society. The results of the present study may be used by policymakers for planning and allocation of resources. Furthermore, the information may be used for future cost-effectiveness analyses.
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32.
  • Tjernström, Fredrik, et al. (författare)
  • Adaptation of postural control to perturbations-a process that initiates long-term motor memory.
  • 2002
  • Ingår i: Gait & Posture. - 1879-2219. ; 15:1, s. 75-82
  • Tidskriftsartikel (refereegranskat)abstract
    • The objective was to investigate postural control adaptation during daily repeated posturography with vibratory calf stimulation. The posturography was performed with eyes open and closed daily for 5 days and after 90 days on 12 healthy subjects. The postural control adaptation could be described as two separate processes, a rapid adaptation during the test progress and a long-term habituation between consecutive test days. The adaptive improvements gained during the 5 days consecutive testing, largely remained 90 days later but seemed restricted to the same test situation. The findings suggest that balance rehabilitation should include a variety of repeated exercises, which are sufficiently long to induce habituation.
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