Francois R Herrmann | Université de Genève (original) (raw)

Papers by Francois R Herrmann

Information De La Societe Suisse De Gerontologie, 2006

Les personnes âgées qui se fracturent l'extrémité proximale du fémur dans des conditions banales ... more Les personnes âgées qui se fracturent l'extrémité proximale du fémur dans des conditions banales (chute de leur hauteur), souffrent de sous-alimentation dans près de 80% des cas. Cette sous-alimentation, par manque d'apports, est surtout protéoénergétique. Plus de la moitié des personnes âgées qui se fracturent vivent chez elles, à domicile, les autres en institutions. La sous-alimentation précède la chute et la fracture de l'os fragilisé. Nous proposons de retenir la fracture de l'extrémité proximale du fémur comme un indicateur de fragilité, de précarité et de carences nutritionnelles des personnes âgées. Pour intervenir auprès des personnes âgées dans nos communautés, il faut déterminer les régions ou les zones socio-sanitaires où il y a le plus grand nombre de fracturés vivant à domicile, où il y a la plus grande incidence et où la moyenne d'âge des fracturés est la plus basse : c'est l'objectif d'un observatoire des fractures de hanche, en particulier quand nos moyens d'intervention sont limités. Un observatoire des fractures de hanche permet aussi de mesurer l'effet des interventions de promotion de la santé, de prévention et de prise en soin ; nous devons pouvoir mesurer les effets sur le nombre, sur l'incidence et sur l'âge moyen des patientes et des patients fracturés. L'observatoire genevois de la fracture de la hanche, initié en 2001, couvre maintenant une décennie de données rétrospectives. Les premiers résultats issus de l'observatoire mettent en évidence, pour les personnes résidant dans leur domicile privé, un risque accru de fracture de la hanche et un âge de survenu de la fracture plus précoce en ville par rapport à la campagne. En affinant ce résultat, nous avons identifié des quartiers à Genève où l'incidence est plus forte et la moyenne d'âge des fracturés plus basse par rapport à d'autres quartiers (ceci avec contrôle des effets d'âge et de sexe). Ces différences s'expliquent en partie par le revenu médian des quartiers. L'observatoire

European Journal of Neurology, 2009

Journal of Bone and Mineral Research, 2010

The purpose of this study was to determine whether there was an association between serum 25hydro... more The purpose of this study was to determine whether there was an association between serum 25hydroxyvitamin D [25(OH)D] concentration and walking speed measured at usual and fast pace among older women. Usual-and fast-pace walking speeds and 25(OH)D concentrations were assessed in 739 randomized older women (mean age 80.2 ± 3.5 years) from the EPIDOS study. The following 25(OH)D thresholds were used: 10, 20, and 30 ng/mL. Walking speed was dichotomized on being in the worst quintile or not. Age, body mass index, number of chronic diseases, physical activity, quadriceps strength, cognition, use of psychoactive drugs, and serum parathyroid hormone were used as potential confounders. The results show that 90% of subjects had 25(OH)D insufficiency. Only fast-pace walking speed was significantly different between groups (p = .021) and decreased from normal serum 25(OH)D concentrations to severe insufficiency (trend p = .007). Serum 25(OH)D concentration was associated with walking speed at both usual and fast pace in the unadjusted linear regression (β = 0.16, p = .027 and β = 0.23, p = .009, respectively). This association remained significant only for fast-pace walking after adjustment (adjusted β = 0.18, p = .033) and was strengthened from a lower 25(OH)D value compared with usual pace [25(OH)D = 27.15 ng/mL for fast pace and 38.65 ng/mL for usual

Annales De Gerontologie, 2009

Journal of The American Geriatrics Society, 2005

Objectives: To compare the usefulness of procalcitonin (PCT) in detecting infection in elderly pa... more Objectives: To compare the usefulness of procalcitonin (PCT) in detecting infection in elderly patients with that of other clinical and biological markers.Design: Prospective observational study to compare PCT levels in infected and uninfected patients.Setting: Geriatric teaching hospital in Switzerland.Participants: Two hundred eighteen elderly patients aged 75 and older admitted to an acute geriatric care unit.Measurements: Demographic characteristics, comorbidities, Charlson index, general signs (respiratory rate, temperature, pulse rate, confusion, falls, shivering), presence of systemic inflammatory response syndrome (SIRS), sepsis, severe sepsis, septic shock, functional score (Functional Independence Measurement (FIM)) biological parameters (PCT, C-reactive protein (CRP), leukocytes, albumin), and definite diagnosis at admission were collected prospectively for each patient.Results: Long-term corticotherapy, chronic immune diseases, fever of 38°C or higher, white blood cell count, pulse rate, FIM, SIRS, sepsis, CRP of 3 mg/mL or higher, and PCT of 0.5 ng/mL or higher were associated with an infection at admission. In multivariate analysis, only sepsis and CRP of 3 mg/mL or higher were still associated with an infection; PCT levels do not show any significant association in the multivariate analysis. In addition, when PCT had good specificity (94%), it had low sensitivity (24%). False-negative PCT was related to lower severity of infection (lower inflammatory reaction and lower acute renal failure) than true-positive PCT. This finding may also be related to aging per se.Conclusion: PCT may be useful to identify severely ill elderly patients admitted to an acute geriatric ward but not to discriminate patients with infection from those without.

Aging Clinical and Experimental Research, 2005

Background and aims: Data from the literature reveal the contrasting influences of family members... more Background and aims: Data from the literature reveal the contrasting influences of family members and friends on the survival of old adults. On one hand, numerous studies have reported a positive association between social relationships and survival. On the other, ties with children may be associated with an increased risk of disability, whereas ties with friends or other relatives tend to improve survival. A five-year prospective, population-based study of 295 Swiss octogenarians tested the hypothesis that having a spouse, siblings or close friends, and regular contacts with relatives or friends are associated with longer survival, even at a very old age. Methods: Data were collected through individual interviews, and a Cox regression model was applied to assess the effects of kinship and friendship networks on survival, after adjusting for socio-demographic and health-related variables. Results: Our analyses indicate that the presence of a spouse in the household is not significantly related to survival, whereas the presence of siblings at baseline improves the oldest old's chances of surviving five years later. Moreover, the existence of close friends is a central component in the patterns of social relationships of oldest adults, and one which is significantly associated with survival. Overall, the protective effect of social relationships on survival is more related to the quality of those relationships (close friends) than to the frequency of relationships (regular contacts). Conclusions: We hypothesize that the existence of siblings or close friends may beneficially affect survival, due to the potential influence on the attitudes of octogenarians regarding health practices and adaptive strategies. (Aging Clin Exp Res 2005; 17: 419-425)

Age and Ageing, 2007

To establish whether changes in a spoken verbal task performance while walking compared with bein... more To establish whether changes in a spoken verbal task performance while walking compared with being at rest could predict falls among older adults. Prospective cohort study of 12 months' duration. Twenty-seven senior housing facilities. Sample of 187 subjects aged 75-100 (mean age 84.8 +/- 5.2). During enrollment, participants were asked to count aloud backward from 50, both at rest and while walking and were divided into two groups according to their counting performance. Information on incident falls during the follow-up year was monthly collected. The number of enumerated figures while sitting on a chair and while walking, and the first fall that occurred during the follow up year. The number of enumerated figures under dual-task as compared to single task increased among 31.5% of the tested subjects (n = 59) and was associated with lower scores in MMSE (P = 0.034), and higher scores in Geriatric Depression Scale (P = 0.007) and Timed Up & Go (P = 0.005). During the 12 months follow-up, 54 subjects (28.9%) fell. After adjusting for these variables, the increase in counting performance was significantly associated with falls (adjusted OR = 53.3, P < 0.0001). Kaplan-Meier distributions of falls differed significantly between subjects who either increased or decreased their counting performance (P < 0.0001). Faster counting while walking was strongly associated with falls, suggesting that better performance in an additional verbal counting task while walking might represent a new way to predict falls among older adults.

Aging Clinical and Experimental Research, 2005

Gait changes in dual-task conditions have been associated with an increased risk of falling in ol... more Gait changes in dual-task conditions have been associated with an increased risk of falling in older adults, and become more important in increasingly frail older adults. We studied the relationship between commonly known intrinsic risk factors for falls and dual-task related gait changes among transitional frail older adults. Walking time and number of steps were measured while walking alone and while walking with counting backward on a 10-m walkway in 66 transitional frail older adults (mean age 83.6+/-6.1, 84.9% women). Uni- and multiple linear regression analyses were performed to explore the relationship between dual-task related gait changes (walking time and number of steps) and age over 85 years, polymedication, psychoactive drugs, poor distance vision, abnormal mobility and cognitive impairment. Compared with walking alone, both walking time and number of steps increased significantly while counting backward (p<0.001). Polymedication and abnormal mobility were associated with a significant increase of walking time and number of steps (p<0.01 for unadjusted change, p<0.05 for adjusted change). Dual-task related gait changes were closely correlated with polymedication and impaired mobility in our sample of transitional frail older adults. These findings give some insight into the complexity of performing attention-demanding tasks while walking and accentuate the need for multi-factorial, personalized intervention strategies, to prevent decline in dual-task performance in this fall-prone population.

Human Movement Science, 2006

Dual-task related gait changes have been previously reported for healthy older adults, suggesting... more Dual-task related gait changes have been previously reported for healthy older adults, suggesting that gait control requires attention. Compared to balance control, the involvement of attention in the control of the rhythmic stepping mechanism, as reflected by stride time variability, is not well known. In particular, under dual-task, the relative contributions of a second, attention-demanding task and changes in walking speed remain unclear. Thus, the aims of this study were (1) to assess whether walking with a slow-selected speed or walking while performing an attention-demanding task affected stride time variability in a sample of healthy older participants, and (2) to establish whether stride time variability under dual-task conditions is related either to the decrease of walking speed or the simultaneous attention-demanding task, or to both. Forty-five healthy older participants performed four experimental conditions: (1) walking at a normal self-selected speed, (2) walking at a slow self-selected speed, (3) performing a verbal fluency task when sitting on a chair, and (4) performing the verbal fluency task while walking at self-selected walking speed. Gait parameters were recorded across 15 meters, using Physilog Ò . Results showed a significant dual-task related decrease 0167-9457/$ -see front matter Ó in mean values of stride velocity, as well as a significant increase in mean values and coefficients of variation of stride time. These dual-task related changes in stride time were explained by the simultaneous performance of the verbal fluency task, the decrease of gait speed and the variability between participants. Although a relationship exists between decreased walking speed and increased stride time variability, the dual-task related increase of stride time variability was also significantly associated with the attention-demanding task, suggesting some attentional control for the rhythmic stepping mechanism of walking in healthy older adults.

European Journal of Neurology, 2009

The objective of this study was to systematically review all published articles examining the rel... more The objective of this study was to systematically review all published articles examining the relationship between the occurrence of falls and changes in gait and attention-demanding task performance whilst dual tasking amongst older adults. An English and French Medline and Cochrane library search ranging from 1997 to 2008 indexed under Ôaccidental fallsÕ, Ôaged OR aged, 80 and overÕ, Ôdual taskÕ, Ôdual taskingÕ, ÔgaitÕ, ÔwalkingÕ, ÔfallÕ and ÔfallingÕ was performed. Of 121 selected studies, fifteen met the selection criteria and were included in the final analysis. The fall rate ranged from 11.1% to 50.0% in retrospective studies and from 21.3% to 42.3% in prospective ones. Amongst the three retrospective and eight prospective studies, two and six studies, respectively, showed a significant relationship between changes in gait performance under dual task and history of falls. The predictive value for falling was particularly efficient amongst frail older adults compared with healthy subjects. Two prospective studies challenged the usefulness of the dual-task paradigm as a significant predictor compared to single task performance and three studies even reported that gait changes whilst dual tasking did not predict falls. The pooled odds ratio for falling was 5.3 (95% CI, 3.1-9.1) when subjects had changes in gait or attention-demanding task performance whilst dual tasking. Despite conflicting early reports, changes in performance whilst dual tasking were significantly associated with an increased risk for falling amongst older adults and frail older adults in particular. Description of health status, standardization of test methodology, increase of sample size and longer follow-up intervals will certainly improve the predictive value of dual-task-based fall risk assessment tests.

Gait & Posture, 2007

Gait disorders caused by dementia have been associated with frontal lobe dysfunction. Dual-taskin... more Gait disorders caused by dementia have been associated with frontal lobe dysfunction. Dual-tasking is used to explore the involvement of cortical level in gait control. It has been shown that dual-task induced gait changes that could be related to (1) the efficiency of executive function, (2) the level of difficulty involved in the walking-associated task, or (3) the articulo-motor components comprised in the walking-associated task. A better understanding of dual-task related changes in demented subjects with frontal lobe dysfunction could help us to clarify the role of the frontal lobe in motor gait control. To assess and compare the effects of two mental arithmetic tasks involving similar articulo-motor components but different level of difficulty on the mean values and coefficient of variation (CV) of stride time among demented older adults with impaired executive function. The mean values and coefficients of variation of stride time were measured using a GAITRite-System among 16 demented older adults with impaired executive function while walking with and without forward counting (FC) and backward counting (BC). The mean values and CV of stride time were significantly higher under both dual-task conditions than during a simple walking task (p<0.05). The change in CV of stride time during BC was significantly higher when compared with the change during FC (p=0.015), whereas the change in mean value was not significant (p=0.056). There was no difference between the dual-task and single task condition as far the number of enumerated figures were concerned (p=0.678 for FC and p=0.069 for BC), but significantly fewer figures were enumerated while BC compared with FC (p<0.001). BC provoked more changes in gait parameters than FC with major modification in gait variability related to an inappropriate focusing of attention. These findings suggest that the CV may be a suitable criterion for the assessment of gait control.

Journal of Psychosomatic Research, 2015

Clinical Oral Implants Research, 2015

This in vitro study evaluated the influence of implant angulations on the retentive behavior of t... more This in vitro study evaluated the influence of implant angulations on the retentive behavior of two overdenture attachments during cyclic dislodging. Models simulating a two-implant overdenture situation were fabricated. They were divided into five groups based on their simulated implant angulations (Groups: 1 = 0°; 2 = 20°; 3 = 30°; 4 = 40°; and 5 = 60°; n = 90). Each group was further divided into two subgroups based on its attachment system (control attachment: LOCATOR(®) ; test attachment: SFI-Anchor(®) ) except for group 5 which had no LOCATOR(®) group. All models underwent 10,000 insertion-removal cycles in a wet environment. Mean retentive forces were recorded. ANOVA and linear regression models were used for statistical analyses, and the level of significance was at P < 0.05. The ANOVA model revealed an effect of dislodging cycles for both attachments (P = 0.0070). The linear regression model with repeated measures revealed a significant effect of angulation within the LOCATOR(®) groups (0° vs. 20°: P < 0.0001; 0° vs. 30°: P < 0.0001; 0° vs. 40°: P < 0.0001), but was insignificant within the SFI-Anchor(®) groups (0° vs. 20°: P = 0.544; 0° vs. 30°: P = 0.134; 0° vs. 40°: P = 0.254; 0° vs. 60°: P = 0.979). It further revealed a significant increase in the retentive force between the LOCATOR(®) and the SFI-Anchor(®) (20°: P = 0.041; 30°: P < 0.0001; 40°: P < 0.0001), although there was no significant difference between the attachments at 0° (P = 0.623). This study confirms that the retentive behavior of SFI-Anchor(®) is not influenced by implant axial inclination even at angulations of up to 60°. The SFI-Anchor(®) may therefore be particularly indicated for clinical situations with marked implant axial discrepancies.

Osteoporosis International, 2011

In this prospective, 10-year study in communitydwelling elderly aged 50 years and over, hip fract... more In this prospective, 10-year study in communitydwelling elderly aged 50 years and over, hip fracture incidence and accordingly age at hip fracture were inversely associated with the area-level income, independently of the geographical area. Age at hip fracture also depended of marital status but in a gender-specific way.

Osteoporosis International, 2008

In this prospective 10-year study in elderly aged 60 years and over, there was a 1.3% per year re... more In this prospective 10-year study in elderly aged 60 years and over, there was a 1.3% per year reduction in the standardized incidence of hip fracture in women but not in men. This decrease was mainly due to changes in the standardized incidence of hip fracture in institutiondwelling women.

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Revue médicale suisse, Jan 13, 2007

Hip fractures are a major cause of burden associated with osteoporosis in terms of mortality, dis... more Hip fractures are a major cause of burden associated with osteoporosis in terms of mortality, disability, and costs. Many studies reveal an increase of the age-adjusted hip fracture incidence but long-term data on secular changes in women and men within a well-defined community are still rare. From 1991 to 2000, 4115 hip fractures were recorded in Geneva in 2981 women and 822 men 50 years and older. Over this 10-year period, the age-adjusted incidence of hip fractures, standardized to the 2000 Geneva population, decreased significantly by 1.4%/year in women (p = 0.021), but remained stable in men (+0.5%/year, p = 0.66), suggesting a reversal of the previously observed secular trend.

To examine whether older people with markedly dual task-related decreases in walking speed - a ma... more To examine whether older people with markedly dual task-related decreases in walking speed - a marker of disturbed higher-level gait control and falls - have a larger discrepancy between real and imagined Timed Up and Go (TUG) test times than those with less dual task-related decreases in walking speed. Based on a prospective cross-sectional study, 193 older adults (mean age 77.4 ± 5.9 years; 44.0 % women) referred to and consecutively assessed at a Swiss university clinic for a gait analysis to assess either gait disorders, fall risk or memory disorders were included. For all participants, walking speed was measured using a GAITRite(®) electronic walkway system during usual walking at self-selected pace and while dual tasking (i.e., usual walking and simultaneously counting backwards out loud). In addition, real Timed Up and Go (TUGr) and imagined Timed Up and Go (TUGi) (i.e., the time needed to imagine performing the TUGr) times were measured with a stopwatch. Differences between both walking conditions for walking speed (delta of walking speed) and both TUG conditions (delta of TUG time) were calculated. Age, gender, height, total number drugs taken per day, daily use of psychoactive drugs, use of walking aid, history of falls, Mini-Mental State Examination score, near vision and education level were used as covariables in this analysis. Participants were categorized into two groups based on being in the lowest tertian (i.e., <33 %: group A corresponding to participants undisturbed by dual task) or not (i.e., ≥33 %: group B corresponding to participants disturbed by dual task) of the delta of walking speed. In both groups, TUGr and TUGi times were similar (P = .169 and P = .839). In both groups, TUGi was faster than TUGr (P < .001). Delta of TUG time was significantly greater in group B compared to group A (P < .001). After adjustment for all covariables, only the delta of walking speed was significantly associated with the delta of TUG time (P = <.001). Stepwise backward regression showed that polypharmacy (P = .017) and delta of walking speed (P = <.001) were associated with an increase in delta of TUG time, whereas an increased MMSE score (P = .030) was associated with a decrease in delta of TUG time. These findings show that a large discrepancy between real and imagined TUG performances is significantly correlated with a decrease in walking speed while dual tasking, and thus may also be a surrogate marker of disturbed higher-level gait control. The quickly and easily performed TUG tests may represent a feasible, practical screening tool for early detection of higher-level gait disorders in older adults.

FEBS Letters, 2006

To understand the role of the superoxide-generating NADPH oxidase NOX1 in the vascular system, we... more To understand the role of the superoxide-generating NADPH oxidase NOX1 in the vascular system, we have generated NOX1-deficient mice. NOX1-deficient mice had a moderately decreased basal blood pressure. In response to angiotensin II they showed an almost complete loss of the sustained blood pressure response, while the initial increase was conserved. NOX1-deficient mice showed a marked reduction in aortic media hypertrophy. Angiotensin II-induced smooth muscle cell proliferation was conserved, but there was a marked decrease in extracellular matrix accumulation. Our results establish a role for NOX1 in blood pressure regulation and vascular angiotensin II response.

Information De La Societe Suisse De Gerontologie, 2006

Les personnes âgées qui se fracturent l'extrémité proximale du fémur dans des conditions banales ... more Les personnes âgées qui se fracturent l'extrémité proximale du fémur dans des conditions banales (chute de leur hauteur), souffrent de sous-alimentation dans près de 80% des cas. Cette sous-alimentation, par manque d'apports, est surtout protéoénergétique. Plus de la moitié des personnes âgées qui se fracturent vivent chez elles, à domicile, les autres en institutions. La sous-alimentation précède la chute et la fracture de l'os fragilisé. Nous proposons de retenir la fracture de l'extrémité proximale du fémur comme un indicateur de fragilité, de précarité et de carences nutritionnelles des personnes âgées. Pour intervenir auprès des personnes âgées dans nos communautés, il faut déterminer les régions ou les zones socio-sanitaires où il y a le plus grand nombre de fracturés vivant à domicile, où il y a la plus grande incidence et où la moyenne d'âge des fracturés est la plus basse : c'est l'objectif d'un observatoire des fractures de hanche, en particulier quand nos moyens d'intervention sont limités. Un observatoire des fractures de hanche permet aussi de mesurer l'effet des interventions de promotion de la santé, de prévention et de prise en soin ; nous devons pouvoir mesurer les effets sur le nombre, sur l'incidence et sur l'âge moyen des patientes et des patients fracturés. L'observatoire genevois de la fracture de la hanche, initié en 2001, couvre maintenant une décennie de données rétrospectives. Les premiers résultats issus de l'observatoire mettent en évidence, pour les personnes résidant dans leur domicile privé, un risque accru de fracture de la hanche et un âge de survenu de la fracture plus précoce en ville par rapport à la campagne. En affinant ce résultat, nous avons identifié des quartiers à Genève où l'incidence est plus forte et la moyenne d'âge des fracturés plus basse par rapport à d'autres quartiers (ceci avec contrôle des effets d'âge et de sexe). Ces différences s'expliquent en partie par le revenu médian des quartiers. L'observatoire

European Journal of Neurology, 2009

Journal of Bone and Mineral Research, 2010

The purpose of this study was to determine whether there was an association between serum 25hydro... more The purpose of this study was to determine whether there was an association between serum 25hydroxyvitamin D [25(OH)D] concentration and walking speed measured at usual and fast pace among older women. Usual-and fast-pace walking speeds and 25(OH)D concentrations were assessed in 739 randomized older women (mean age 80.2 ± 3.5 years) from the EPIDOS study. The following 25(OH)D thresholds were used: 10, 20, and 30 ng/mL. Walking speed was dichotomized on being in the worst quintile or not. Age, body mass index, number of chronic diseases, physical activity, quadriceps strength, cognition, use of psychoactive drugs, and serum parathyroid hormone were used as potential confounders. The results show that 90% of subjects had 25(OH)D insufficiency. Only fast-pace walking speed was significantly different between groups (p = .021) and decreased from normal serum 25(OH)D concentrations to severe insufficiency (trend p = .007). Serum 25(OH)D concentration was associated with walking speed at both usual and fast pace in the unadjusted linear regression (β = 0.16, p = .027 and β = 0.23, p = .009, respectively). This association remained significant only for fast-pace walking after adjustment (adjusted β = 0.18, p = .033) and was strengthened from a lower 25(OH)D value compared with usual pace [25(OH)D = 27.15 ng/mL for fast pace and 38.65 ng/mL for usual

Annales De Gerontologie, 2009

Journal of The American Geriatrics Society, 2005

Objectives: To compare the usefulness of procalcitonin (PCT) in detecting infection in elderly pa... more Objectives: To compare the usefulness of procalcitonin (PCT) in detecting infection in elderly patients with that of other clinical and biological markers.Design: Prospective observational study to compare PCT levels in infected and uninfected patients.Setting: Geriatric teaching hospital in Switzerland.Participants: Two hundred eighteen elderly patients aged 75 and older admitted to an acute geriatric care unit.Measurements: Demographic characteristics, comorbidities, Charlson index, general signs (respiratory rate, temperature, pulse rate, confusion, falls, shivering), presence of systemic inflammatory response syndrome (SIRS), sepsis, severe sepsis, septic shock, functional score (Functional Independence Measurement (FIM)) biological parameters (PCT, C-reactive protein (CRP), leukocytes, albumin), and definite diagnosis at admission were collected prospectively for each patient.Results: Long-term corticotherapy, chronic immune diseases, fever of 38°C or higher, white blood cell count, pulse rate, FIM, SIRS, sepsis, CRP of 3 mg/mL or higher, and PCT of 0.5 ng/mL or higher were associated with an infection at admission. In multivariate analysis, only sepsis and CRP of 3 mg/mL or higher were still associated with an infection; PCT levels do not show any significant association in the multivariate analysis. In addition, when PCT had good specificity (94%), it had low sensitivity (24%). False-negative PCT was related to lower severity of infection (lower inflammatory reaction and lower acute renal failure) than true-positive PCT. This finding may also be related to aging per se.Conclusion: PCT may be useful to identify severely ill elderly patients admitted to an acute geriatric ward but not to discriminate patients with infection from those without.

Aging Clinical and Experimental Research, 2005

Background and aims: Data from the literature reveal the contrasting influences of family members... more Background and aims: Data from the literature reveal the contrasting influences of family members and friends on the survival of old adults. On one hand, numerous studies have reported a positive association between social relationships and survival. On the other, ties with children may be associated with an increased risk of disability, whereas ties with friends or other relatives tend to improve survival. A five-year prospective, population-based study of 295 Swiss octogenarians tested the hypothesis that having a spouse, siblings or close friends, and regular contacts with relatives or friends are associated with longer survival, even at a very old age. Methods: Data were collected through individual interviews, and a Cox regression model was applied to assess the effects of kinship and friendship networks on survival, after adjusting for socio-demographic and health-related variables. Results: Our analyses indicate that the presence of a spouse in the household is not significantly related to survival, whereas the presence of siblings at baseline improves the oldest old's chances of surviving five years later. Moreover, the existence of close friends is a central component in the patterns of social relationships of oldest adults, and one which is significantly associated with survival. Overall, the protective effect of social relationships on survival is more related to the quality of those relationships (close friends) than to the frequency of relationships (regular contacts). Conclusions: We hypothesize that the existence of siblings or close friends may beneficially affect survival, due to the potential influence on the attitudes of octogenarians regarding health practices and adaptive strategies. (Aging Clin Exp Res 2005; 17: 419-425)

Age and Ageing, 2007

To establish whether changes in a spoken verbal task performance while walking compared with bein... more To establish whether changes in a spoken verbal task performance while walking compared with being at rest could predict falls among older adults. Prospective cohort study of 12 months' duration. Twenty-seven senior housing facilities. Sample of 187 subjects aged 75-100 (mean age 84.8 +/- 5.2). During enrollment, participants were asked to count aloud backward from 50, both at rest and while walking and were divided into two groups according to their counting performance. Information on incident falls during the follow-up year was monthly collected. The number of enumerated figures while sitting on a chair and while walking, and the first fall that occurred during the follow up year. The number of enumerated figures under dual-task as compared to single task increased among 31.5% of the tested subjects (n = 59) and was associated with lower scores in MMSE (P = 0.034), and higher scores in Geriatric Depression Scale (P = 0.007) and Timed Up & Go (P = 0.005). During the 12 months follow-up, 54 subjects (28.9%) fell. After adjusting for these variables, the increase in counting performance was significantly associated with falls (adjusted OR = 53.3, P < 0.0001). Kaplan-Meier distributions of falls differed significantly between subjects who either increased or decreased their counting performance (P < 0.0001). Faster counting while walking was strongly associated with falls, suggesting that better performance in an additional verbal counting task while walking might represent a new way to predict falls among older adults.

Aging Clinical and Experimental Research, 2005

Gait changes in dual-task conditions have been associated with an increased risk of falling in ol... more Gait changes in dual-task conditions have been associated with an increased risk of falling in older adults, and become more important in increasingly frail older adults. We studied the relationship between commonly known intrinsic risk factors for falls and dual-task related gait changes among transitional frail older adults. Walking time and number of steps were measured while walking alone and while walking with counting backward on a 10-m walkway in 66 transitional frail older adults (mean age 83.6+/-6.1, 84.9% women). Uni- and multiple linear regression analyses were performed to explore the relationship between dual-task related gait changes (walking time and number of steps) and age over 85 years, polymedication, psychoactive drugs, poor distance vision, abnormal mobility and cognitive impairment. Compared with walking alone, both walking time and number of steps increased significantly while counting backward (p<0.001). Polymedication and abnormal mobility were associated with a significant increase of walking time and number of steps (p<0.01 for unadjusted change, p<0.05 for adjusted change). Dual-task related gait changes were closely correlated with polymedication and impaired mobility in our sample of transitional frail older adults. These findings give some insight into the complexity of performing attention-demanding tasks while walking and accentuate the need for multi-factorial, personalized intervention strategies, to prevent decline in dual-task performance in this fall-prone population.

Human Movement Science, 2006

Dual-task related gait changes have been previously reported for healthy older adults, suggesting... more Dual-task related gait changes have been previously reported for healthy older adults, suggesting that gait control requires attention. Compared to balance control, the involvement of attention in the control of the rhythmic stepping mechanism, as reflected by stride time variability, is not well known. In particular, under dual-task, the relative contributions of a second, attention-demanding task and changes in walking speed remain unclear. Thus, the aims of this study were (1) to assess whether walking with a slow-selected speed or walking while performing an attention-demanding task affected stride time variability in a sample of healthy older participants, and (2) to establish whether stride time variability under dual-task conditions is related either to the decrease of walking speed or the simultaneous attention-demanding task, or to both. Forty-five healthy older participants performed four experimental conditions: (1) walking at a normal self-selected speed, (2) walking at a slow self-selected speed, (3) performing a verbal fluency task when sitting on a chair, and (4) performing the verbal fluency task while walking at self-selected walking speed. Gait parameters were recorded across 15 meters, using Physilog Ò . Results showed a significant dual-task related decrease 0167-9457/$ -see front matter Ó in mean values of stride velocity, as well as a significant increase in mean values and coefficients of variation of stride time. These dual-task related changes in stride time were explained by the simultaneous performance of the verbal fluency task, the decrease of gait speed and the variability between participants. Although a relationship exists between decreased walking speed and increased stride time variability, the dual-task related increase of stride time variability was also significantly associated with the attention-demanding task, suggesting some attentional control for the rhythmic stepping mechanism of walking in healthy older adults.

European Journal of Neurology, 2009

The objective of this study was to systematically review all published articles examining the rel... more The objective of this study was to systematically review all published articles examining the relationship between the occurrence of falls and changes in gait and attention-demanding task performance whilst dual tasking amongst older adults. An English and French Medline and Cochrane library search ranging from 1997 to 2008 indexed under Ôaccidental fallsÕ, Ôaged OR aged, 80 and overÕ, Ôdual taskÕ, Ôdual taskingÕ, ÔgaitÕ, ÔwalkingÕ, ÔfallÕ and ÔfallingÕ was performed. Of 121 selected studies, fifteen met the selection criteria and were included in the final analysis. The fall rate ranged from 11.1% to 50.0% in retrospective studies and from 21.3% to 42.3% in prospective ones. Amongst the three retrospective and eight prospective studies, two and six studies, respectively, showed a significant relationship between changes in gait performance under dual task and history of falls. The predictive value for falling was particularly efficient amongst frail older adults compared with healthy subjects. Two prospective studies challenged the usefulness of the dual-task paradigm as a significant predictor compared to single task performance and three studies even reported that gait changes whilst dual tasking did not predict falls. The pooled odds ratio for falling was 5.3 (95% CI, 3.1-9.1) when subjects had changes in gait or attention-demanding task performance whilst dual tasking. Despite conflicting early reports, changes in performance whilst dual tasking were significantly associated with an increased risk for falling amongst older adults and frail older adults in particular. Description of health status, standardization of test methodology, increase of sample size and longer follow-up intervals will certainly improve the predictive value of dual-task-based fall risk assessment tests.

Gait & Posture, 2007

Gait disorders caused by dementia have been associated with frontal lobe dysfunction. Dual-taskin... more Gait disorders caused by dementia have been associated with frontal lobe dysfunction. Dual-tasking is used to explore the involvement of cortical level in gait control. It has been shown that dual-task induced gait changes that could be related to (1) the efficiency of executive function, (2) the level of difficulty involved in the walking-associated task, or (3) the articulo-motor components comprised in the walking-associated task. A better understanding of dual-task related changes in demented subjects with frontal lobe dysfunction could help us to clarify the role of the frontal lobe in motor gait control. To assess and compare the effects of two mental arithmetic tasks involving similar articulo-motor components but different level of difficulty on the mean values and coefficient of variation (CV) of stride time among demented older adults with impaired executive function. The mean values and coefficients of variation of stride time were measured using a GAITRite-System among 16 demented older adults with impaired executive function while walking with and without forward counting (FC) and backward counting (BC). The mean values and CV of stride time were significantly higher under both dual-task conditions than during a simple walking task (p<0.05). The change in CV of stride time during BC was significantly higher when compared with the change during FC (p=0.015), whereas the change in mean value was not significant (p=0.056). There was no difference between the dual-task and single task condition as far the number of enumerated figures were concerned (p=0.678 for FC and p=0.069 for BC), but significantly fewer figures were enumerated while BC compared with FC (p<0.001). BC provoked more changes in gait parameters than FC with major modification in gait variability related to an inappropriate focusing of attention. These findings suggest that the CV may be a suitable criterion for the assessment of gait control.

Journal of Psychosomatic Research, 2015

Clinical Oral Implants Research, 2015

This in vitro study evaluated the influence of implant angulations on the retentive behavior of t... more This in vitro study evaluated the influence of implant angulations on the retentive behavior of two overdenture attachments during cyclic dislodging. Models simulating a two-implant overdenture situation were fabricated. They were divided into five groups based on their simulated implant angulations (Groups: 1 = 0°; 2 = 20°; 3 = 30°; 4 = 40°; and 5 = 60°; n = 90). Each group was further divided into two subgroups based on its attachment system (control attachment: LOCATOR(®) ; test attachment: SFI-Anchor(®) ) except for group 5 which had no LOCATOR(®) group. All models underwent 10,000 insertion-removal cycles in a wet environment. Mean retentive forces were recorded. ANOVA and linear regression models were used for statistical analyses, and the level of significance was at P < 0.05. The ANOVA model revealed an effect of dislodging cycles for both attachments (P = 0.0070). The linear regression model with repeated measures revealed a significant effect of angulation within the LOCATOR(®) groups (0° vs. 20°: P < 0.0001; 0° vs. 30°: P < 0.0001; 0° vs. 40°: P < 0.0001), but was insignificant within the SFI-Anchor(®) groups (0° vs. 20°: P = 0.544; 0° vs. 30°: P = 0.134; 0° vs. 40°: P = 0.254; 0° vs. 60°: P = 0.979). It further revealed a significant increase in the retentive force between the LOCATOR(®) and the SFI-Anchor(®) (20°: P = 0.041; 30°: P < 0.0001; 40°: P < 0.0001), although there was no significant difference between the attachments at 0° (P = 0.623). This study confirms that the retentive behavior of SFI-Anchor(®) is not influenced by implant axial inclination even at angulations of up to 60°. The SFI-Anchor(®) may therefore be particularly indicated for clinical situations with marked implant axial discrepancies.

Osteoporosis International, 2011

In this prospective, 10-year study in communitydwelling elderly aged 50 years and over, hip fract... more In this prospective, 10-year study in communitydwelling elderly aged 50 years and over, hip fracture incidence and accordingly age at hip fracture were inversely associated with the area-level income, independently of the geographical area. Age at hip fracture also depended of marital status but in a gender-specific way.

Osteoporosis International, 2008

In this prospective 10-year study in elderly aged 60 years and over, there was a 1.3% per year re... more In this prospective 10-year study in elderly aged 60 years and over, there was a 1.3% per year reduction in the standardized incidence of hip fracture in women but not in men. This decrease was mainly due to changes in the standardized incidence of hip fracture in institutiondwelling women.

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Revue médicale suisse, Jan 13, 2007

Hip fractures are a major cause of burden associated with osteoporosis in terms of mortality, dis... more Hip fractures are a major cause of burden associated with osteoporosis in terms of mortality, disability, and costs. Many studies reveal an increase of the age-adjusted hip fracture incidence but long-term data on secular changes in women and men within a well-defined community are still rare. From 1991 to 2000, 4115 hip fractures were recorded in Geneva in 2981 women and 822 men 50 years and older. Over this 10-year period, the age-adjusted incidence of hip fractures, standardized to the 2000 Geneva population, decreased significantly by 1.4%/year in women (p = 0.021), but remained stable in men (+0.5%/year, p = 0.66), suggesting a reversal of the previously observed secular trend.

To examine whether older people with markedly dual task-related decreases in walking speed - a ma... more To examine whether older people with markedly dual task-related decreases in walking speed - a marker of disturbed higher-level gait control and falls - have a larger discrepancy between real and imagined Timed Up and Go (TUG) test times than those with less dual task-related decreases in walking speed. Based on a prospective cross-sectional study, 193 older adults (mean age 77.4 ± 5.9 years; 44.0 % women) referred to and consecutively assessed at a Swiss university clinic for a gait analysis to assess either gait disorders, fall risk or memory disorders were included. For all participants, walking speed was measured using a GAITRite(®) electronic walkway system during usual walking at self-selected pace and while dual tasking (i.e., usual walking and simultaneously counting backwards out loud). In addition, real Timed Up and Go (TUGr) and imagined Timed Up and Go (TUGi) (i.e., the time needed to imagine performing the TUGr) times were measured with a stopwatch. Differences between both walking conditions for walking speed (delta of walking speed) and both TUG conditions (delta of TUG time) were calculated. Age, gender, height, total number drugs taken per day, daily use of psychoactive drugs, use of walking aid, history of falls, Mini-Mental State Examination score, near vision and education level were used as covariables in this analysis. Participants were categorized into two groups based on being in the lowest tertian (i.e., <33 %: group A corresponding to participants undisturbed by dual task) or not (i.e., ≥33 %: group B corresponding to participants disturbed by dual task) of the delta of walking speed. In both groups, TUGr and TUGi times were similar (P = .169 and P = .839). In both groups, TUGi was faster than TUGr (P < .001). Delta of TUG time was significantly greater in group B compared to group A (P < .001). After adjustment for all covariables, only the delta of walking speed was significantly associated with the delta of TUG time (P = <.001). Stepwise backward regression showed that polypharmacy (P = .017) and delta of walking speed (P = <.001) were associated with an increase in delta of TUG time, whereas an increased MMSE score (P = .030) was associated with a decrease in delta of TUG time. These findings show that a large discrepancy between real and imagined TUG performances is significantly correlated with a decrease in walking speed while dual tasking, and thus may also be a surrogate marker of disturbed higher-level gait control. The quickly and easily performed TUG tests may represent a feasible, practical screening tool for early detection of higher-level gait disorders in older adults.

FEBS Letters, 2006

To understand the role of the superoxide-generating NADPH oxidase NOX1 in the vascular system, we... more To understand the role of the superoxide-generating NADPH oxidase NOX1 in the vascular system, we have generated NOX1-deficient mice. NOX1-deficient mice had a moderately decreased basal blood pressure. In response to angiotensin II they showed an almost complete loss of the sustained blood pressure response, while the initial increase was conserved. NOX1-deficient mice showed a marked reduction in aortic media hypertrophy. Angiotensin II-induced smooth muscle cell proliferation was conserved, but there was a marked decrease in extracellular matrix accumulation. Our results establish a role for NOX1 in blood pressure regulation and vascular angiotensin II response.