The Gait Disorder in Downbeat Nystagmus Syndrome

Background: Downbeat nystagmus (DBN) is a common form of acquired fixation nystagmus with key symptoms of oscillopsia and gait disturbance. Gait disturbance could be a result of impaired visual feedback due to the involuntary ocular oscillations. Alternatively, a malfunction of cerebellar locomotor control might be involved, since DBN is considered a vestibulocerebellar disorder. Methods: Investigation of walking in 50 DBN patients (age 72 +/- 11 years, 23 females) and 50 healthy controls (HS) (age 70 +/- 11 years, 23 females) using a pressure sensitive carpet (GAITRite). The patient cohort comprised subjects with only ocular motor signs (DBN) and subjects with an additional limb ataxia (DBNCA). Gait investigation comprised different walking speeds and walking with eyes closed. Results: In DBN, gait velocity was reduced (p<0.001) with a reduced stride length (p<0.001),increased base of support (p<0.050),and increased double support (p<0.001). Walking with eyes closed led to significant gait changes in both HS and DBN. These changes were more pronounced in DBN patients (p<0.001). Speed-dependency of gait variability revealed significant differences between the subgroups of DBN and DBNCA (p<0.050). Conclusions: (I) Impaired visual control caused by involuntary ocular oscillations cannot sufficiently explain the gait disorder. (II) The gait of patients with DBN is impaired in a speed dependent manner. (III) Analysis of gait variability allows distinguishing DBN from DBNCA: Patients with pure DBN show a speed dependency of gait variability similar to that of patients with afferent vestibular deficits. In DBNCA, gait variability resembles the pattern found in cerebellar ataxia

Quantification of gait changes in subjects with visual height intolerance when exposed to heights

Introduction: Visual height intolerance (vHI) manifests as instability at heights with apprehension of losing balance or falling. We investigated contributions of visual feedback and attention on gait performance of subjects with vHI. Materials and Methods: Sixteen subjects with vHI walked over a gait mat (GAITRite (R)) on a 15-m-high balcony and at ground-level. Subjects walked at different speeds (slow, preferred, fast), during changes of the visual input (gaze straight/up/down;eyes open/closed), and while doing a cognitive task. An rmANOVA with the factors "height situation" and "gait condition" was performed. Subjects were also asked to estimate the height of the balcony over ground level. The individual estimates were used for correlations with the gait parameters. Results: Study participants walked slower at heights, with reduced cadence and stride length. The double support phases were increased (all p < 0.01),which correlated with the estimated height of the balcony (R-2 = 0.453, p < 0.05). These changes were still present when walking with upward gaze or closure of the eyes. Under the conditions walking and looking down to the floor of the balcony, during dual-task and fast walking, there were no differences between the gait performance on the balcony and at ground-level. Discussion: The found gait changes are features of a cautious gait control. Internal, cognitive models with anxiety play an important role for vHI; gait was similarly affected when the visual perception of the depth was prevented. Improvement by dual task at heights may be associated by a reduction of the anxiety level. Conclusion: It is conceivable that mental distraction by dual task or increasing the walking speed might be useful recommendations to reduce the imbalance during locomotion in subjects susceptible to vHI

Sabrina Cauchy, Les bouquetières-chapelières en fleurs à Paris sous l’Ancien Régime

Une bouquetière est une femme qui « fait ou agence des bouquets de fleurs naturelles », telle est la définition donnée par Hurtaut et Magny dans le Dictionnaire historique de la ville de Parisau XVIIIe siècle. Profession existant dès le Moyen Age sous une autre forme, les chapelières de fleurs, c’est un métier entièrement féminin déjà ancien, bien que peu connu. Travaillant probablement pour les jardiniers, les bouquetières se sont constituées progressivement d’elles-mêmes en communauté disti..

Sabrina Cauchy, Les bouquetières-chapelières en fleurs à Paris sous l’Ancien Régime

Une bouquetière est une femme qui « fait ou agence des bouquets de fleurs naturelles », telle est la définition donnée par Hurtaut et Magny dans le Dictionnaire historique de la ville de Parisau XVIIIe siècle. Profession existant dès le Moyen Age sous une autre forme, les chapelières de fleurs, c’est un métier entièrement féminin déjà ancien, bien que peu connu. Travaillant probablement pour les jardiniers, les bouquetières se sont constituées progressivement d’elles-mêmes en communauté disti..

Results of the two-way ANOVA model (DBN vs. HS).

<p>F-Values and p-values are indicated for a 2-way ANOVA (factor “group”: HS, DBN; factor “condition”: walking with slow, preferred and maximal speed, walking with eyes closed).</p><p>Abbreviations: HS - healthy subjects. DBN - downbeat nystagmus syndrome. CV - coefficient of variation.</p

Results of the two-way ANOVA model (DBN subgroups).

<p>F-Values and p-values are indicated for a 2-way ANOVA (factor “group”: DBN/DBN+BVF/DBN+PNP/DBNCA; factor “condition”: walking with slow, preferred and maximal speed, walking with eyes closed).</p><p>Abbreviations: HS - healthy subjects. DBN - downbeat nystagmus syndrome. BVF - bilateral vestibular failure. PNP - sensory neuropathy. CA - cerebellar ataxia. CV - coefficient of variation.</p

Effect of absent visual control on gait variables in DBN and HS.

<p>Box plots of the individual Variation Rates with median, sample minimum and maximum, lower and upper quartile for healthy subjects (grey) and patients with DBN (black). Gait variables were grouped in spatial (A), temporal (B), and variability (C) gait parameters. Conventional spatiotemporal gait parameters were worse in patients with DBN under walking with closed eyes, indicating a higher stabilizing effect of vision on balance control, despite the ocular oscillations in DBN. Note the scale enlargement in the section C of the figure. * indicates p<0.050, ** indicates p<0.010, *** indicates p<0.001 of the two-way ANOVA (factor “group”: HS, DBN; factor “condition”: eyes opened, eyes closed) with Bonferroni posthoc analysis of the interaction effect “group×condition” Abbreviations: HS - healthy subjects. DBN - downbeat nystagmus syndrome. EO - eyes opened. EC - eyes closed.</p

Relative gait changes during walking with eyes opened and eyes closed.

<p>Mean values and standard deviation of the Variation Rates for the different gait variables under walking with eyes closed in respect to walking with eyes opened. F-Values and p-values are indicated for a one-way ANOVA (factor “group”: HS, DBN).</p><p>Abbreviations: HS - healthy subjects. DBN - downbeat nystagmus syndrome. VR - Variation Rates.</p

Quantification of gait changes in subjects with visual height intolerance when exposed to heights

Introduction: Visual height intolerance (vHI) manifests as instability at heights with apprehension of losing balance or falling. We investigated contributions of visual feedback and attention on gait performance of subjects with vHI. Material and Methods: Sixteen subjects with vHI walked over a gait mat (GAITRite®) on a 15-m-high balcony and at ground-level. Subjects walked at different speeds (slow, preferred, fast), during changes of the visual input (gaze straight/ up/ down; eyes open /closed), and while doing a cognitive task. An rmANOVA with the factors height situation and gait condition was performed. Subjects were also asked to estimate the height of the balcony over ground level. The individual estimates were used for correlations with the gait parameters.Results: Study participants walked slower at heights, with reduced cadence and stride length. The double support phases were increased (all p<0.01), which correlated with the estimated height of the balcony (R2=0.453, p<0.05). ). These changes were still present when walking with upward gaze or closure of the eyes. Under the conditions walking and looking down to the floor of the balcony, during dual-task and fast walking, there were no differences between the gait performance on the balcony and at ground-level. Discussion: The found gait changes are features of a cautious gait control. Internal, cognitive models with anxiety play an important role for vHI; gait was similarly affected when the visual perception of the depth was prevented. . Improvement by dual task at heights may be associated by a reduction of the anxiety level.Conclusion: It is conceivable that mental distraction by dual task or increasing the walking speed might be useful recommendations to reduce the imbalance during locomotion in subjects susceptible to vHI

Speed-dependent temporal gait variability.

<p>Boxplots with median, sample minimum and maximum, lower and upper quartile for DBN patients (gray) and HS (black) * indicates p<0.05 of the two-way ANOVA (factor “group”: DBN, HS; factor “speed condition” slow, preferred, maximally fast speed) with posthoc Bonferroni posthoc analysis of the interaction effect “group×condition”. Abbreviations: HS - healthy subjects. DBN - downbeat nystagmus syndrome.</p