Y.P.T. Kamsma

Gait in ageing and associated dementias; its relationship with cognition.

The focus of this review is on the close relationship between gait and cognition in ageing and associated dementias. This close relationship is supported by epidemiological studies, clinical studies of older people with and without dementia that focused on the intensity of the physical activity, clinical studies with older persons without dementia examining a relationship between gait and specific cognitive processes, and human and animal experimental studies examining a neural basis for such a relationship. Despite these findings, most studies with patients with dementia focus exclusively on the relationship between cognition and dementia, with relatively few addressing the relationship between gait and dementia. However, subtle disturbances in gait can be observed in ageing and in (preclinical) subtypes of dementia that are not known for prominent motor disturbances, i.e. Mild Cognitive Impairment, Alzheimers Disease, vascular Cognitive Impairment No Dementia, Subcortical Ischaemic Vascular Dementia, Frontotemporal Mild Cognitive Impairment, and Frontotemporal Dementia, supporting a close relationship between gait and cognition. The relationship between gait and cognition is weakened by the few available intervention studies that examine the effects of walking on cognition in patients with (preclinical) dementia. These studies report equivocal results, which will be discussed. Finally, suggestions for future research will be made.

The effect of a home physiotherapy program for persons with Parkinson's disease

The purpose of this study was to evaluate the effect of a home physiotherapy program for persons with Parkinsons disease. Thirty-three patients took part in the study using a within-subject controlled design. Functional activities including walking and carrying out transfers were measured at home and in the hospital before and after a 6-week baseline period, after 6 weeks home physiotherapy and after 3 months follow-up. Spatiotemporal and plantar force variables of gait were determined with video and pododynography. Treatment provided by community physiotherapists consisted of teaching cueing and conscious movement control 3 times a week. The study revealed that patients had significantly higher scores on a functional activity scale after treatment in the home setting and to a lesser degree in hospital, a result, which was partly sustained at follow-up. However, duration of the transfer movements, spatiotemporal and plantar force variables were not significantly improved except for stride length. The results support application and development of the treatment concept and highlight that physiotherapy aimed at improving function in Parkinsons disease is best provided in the home situation.

Detection of walking periods and number of steps in older adults and patients with Parkinson's disease: accuracy of a pedometer and an accelerometry-based method

The aim of this study was to examine if walking periods and number of steps can accurately be detected by a single small body-fixed device in older adults and patients with Parkinsons disease (PD). Results of an accelerometry-based method (DynaPort MicroMod) and a pedometer (Yamax Digi-Walker SW-200) worn on each hip were evaluated against video observation. Twenty older adults and 32 PD patients walked straight-line trajectories at different speeds, of different lengths and while doing secondary tasks in an indoor hallway. Accuracy of the instruments was expressed as absolute percentage error (older adults versus PD patients). Based on the video observation, a total of 236.8 min of gait duration and 24,713 steps were assessed. The DynaPort method predominantly overestimated gait duration (10.7 versus 11.1%) and underestimated the number of steps (7.4 versus 6.9%). Accuracy decreased significantly as walking distance decreased. Number of steps were also mainly underestimated by the pedometers, the left Yamax (6.8 versus 11.1%) being more accurate than the right Yamax (11.1 versus 16.3%). Step counting of both pedometers was significantly less accurate for short trajectories (3 or 5 m) and as walking pace decreased. It is concluded that the Yamax pedometer can be reliably used for this study population when walking at sufficiently high gait speeds (>1.0 m/s). The accelerometry-based method is less speed-dependent and proved to be more appropriate in the PD patients for walking trajectories of 5 m or more.

Early phenotypic differences between Parkinson's disease patients with and without freezing of gait.

BACKGROUND Previous studies have associated freezing of gait in Parkinsons disease with the presence of specific phenotypic features such as mood disturbances, REM sleep behavior disorder and selective cognitive impairments. However, it is not clear whether these features are present in the earlier stages of disease or simply represent a more general pattern of progression. To investigate this issue, the current study evaluated motor, cognitive, affective and autonomic features as well as REM sleep behavior disorder in Parkinsons disease patients in the early stages of the condition. METHODS Thirty-eight freezers and fifty-three non-freezers with disease duration of less than five years and a Hoehn and Yahr stage of less than three were included in this study. The groups were matched on a number of key disease features including age, disease duration, motor severity and dopamine dose equivalence. Furthermore, patients were assessed on measures of motor, cognitive, affective and autonomic features, as well as REM sleep behavior disorder. RESULTS Compared to non-freezers, patients with freezing of gait had significantly more non-tremor symptoms and a selective impairment on executive functions, such as set-shifting ability and working memory. Freezers and non-freezers did not differ on measures of tremor, autonomic function, REM sleep behavior disorder, mood or more general cognition. CONCLUSION These results suggest the pathophysiological mechanisms underlying freezing of gait in the early clinical stages of Parkinsons disease are likely to be related to specific changes in the frontostriatal pathways rather than being due to brainstem or more diffuse neuropathology.

Variability of Stepping during a Virtual Reality Paradigm in Parkinson's Disease Patients with and without Freezing of Gait

Background Freezing of gait is a common and debilitating symptom affecting many patients with advanced Parkinson’s disease. Although the pathophysiology of freezing of gait is not fully understood, a number of observations regarding the pattern of gait in patients with this symptom have been made. Increased ‘Stride Time Variability’ has been one of the most robust of these features. In this study we sought to identify whether patients with freezing of gait demonstrated similar fluctuations in their stepping rhythm whilst performing a seated virtual reality gait task that has recently been used to demonstrate the neural correlate of the freezing phenomenon. Methods Seventeen patients with freezing and eleven non-freezers performed the virtual reality task twice, once whilst ‘On’ their regular Parkinsonian medication and once in their practically defined ‘Off’ state. Results All patients displayed greater step time variability during their ‘Off’ state assessment compared to when medicated. Additionally, in the ‘Off’ state, patients with freezing of gait had greater step time variability compared to non-freezers. The five steps leading up to a freezing episode in the virtual reality environment showed a significant increase in step time variability although the final three steps preceding the freeze were not characterized by a progressive shortening of latency. Conclusions The results of this study suggest that characteristic features of gait disturbance observed in patients with freezing of gait can also be demonstrated with a virtual reality paradigm. These findings suggest that virtual reality may offer the potential to further explore the freezing phenomenon in Parkinson’s disease.

Daily physical activity in ankylosing spondylitis: validity and reliability of the IPAQ and SQUASH and the relation with clinical assessments.

IntroductionThe aim of this study was to investigate the construct validity and test-retest reliability of the International Physical Activity Questionnaire (IPAQ; long form) and the Short QUestionnaire to Assess Health-enhancing physical activity (SQUASH) and to investigate the relation between daily physical activity and clinical assessments in patients with ankylosing spondylitis (AS).MethodsFor validity, the self-report questionnaires IPAQ and SQUASH were compared with daily physical activity assessed with the ActiGraph accelerometer during 7 consecutive days in 63 AS outpatients. For reliability, the IPAQ and SQUASH were administered twice approximately 1 week apart in 52 AS outpatients. In all 115 patients, clinical assessments were performed at the outpatient clinic.ResultsIPAQ and SQUASH total scores correlated significantly with accelerometer outcome: ρ = 0.38 and r = 0.35, respectively. Intraclass correlation coefficients between first and second assessments of the IPAQ and SQUASH were 0.83 and 0.89, respectively. Bland-Altman analyses showed no systemic bias, but in particular for the IPAQ the 95% limits of agreement were wide. Daily physical activity assessed by accelerometer, IPAQ, and SQUASH correlated significantly with disease activity, physical activity, and quality of life. A relation with spinal mobility was found only for the accelerometer and SQUASH. The direction of these correlations indicates that higher daily physical activity is related to lower disease activity and better physical function, spinal mobility and quality of life.ConclusionsBoth physical activity questionnaires showed modest construct validity. The SQUASH showed good test-retest reliability, superior to the IPAQ. These results indicate that the SQUASH is more suitable than the IPAQ to assess daily physical activity in AS population studies. However, it is desirable to add questions on AS-specific physical activity. Further studies are needed to investigate the causality of the relation between daily physical activity and clinical assessments.

Older adults can improve compensatory stepping with repeated postural perturbations

The ability to respond quickly and accurately to an external perturbation with a stepping response is critical to avoid falls and this ability is impaired in older, compared to young adults. However, little is known about whether young and older adults improve compensatory stepping responses similarly with practice. This study compares the extent to which young and older adults can improve, retain, and generalize postural compensatory steps in response to external perturbations. Centre of mass displacement, step characteristics and lower leg muscle activation latencies were measured during one training session of compensatory stepping in response to large surface translations in 13 young and 12 older adults. Retention was tested 24 h later. Older adults decreased their center of mass displacements over repeated exposure to large surface translations in both the anterior and posterior directions and retained these improvements. In contrast, young adults only showed adaptation and retention of forward stepping responses. Neither group was able to generalize improvements in stepping responses across directions. These results suggest step training may be beneficial for older adults, however additional, multidirectional training may be necessary to facilitate generalization of postural stepping responses for any direction of a slip or trip.

Psychometric Properties of the PAT: An Assessment Tool for ADL Performance of Older People Living in Residential Homes

Background: As the world population ages, the number of people with diminished performance on the Activities of Daily Living (ADL) increases. A reliable and valid measure needs to be developed to determine the effects of interventions focused at increasing self-care abilities. We developed the Performance ADL Test (PAT) for this purpose. Objective: The aim of this study was to investigate the reliability and validity of the PAT in older people living in residential homes. Methods: The PAT contains 16 test items, covering the entire range of Basic ADL and Instrumental ADL performance in elderly people. For this assessment, 40 older people (mean age of 85 ± 7.5 years) participated. All 40 subjects lived in residential institutions in the Netherlands, were able to walk at least 10 m, could understand instructions spoken in Dutch, and had no cognitive impairment. During the first test session, subjects completed the PAT, the Groningen Activity Restriction Scale (GARS), and performance-based physical fitness tests. Two weeks later, subjects were retested on the PAT. Results: Factor analysis revealed three subscales: Organization of Performance, Gross Motor Function, and Fine Motor Function. Internal consistency (Cronbach’s α) of all scales and subscales ranged from 0.731 to 0.881. Test-retest reliability (intraclass correlation) ranged from 0.316 to 0.950. Paired sample t-tests revealed no significant differences between subject performance obtained during the two test periods. Pearson’s correlations between the PAT and the GARS ranged from 0.490 to 0.831, and between the PAT and the fitness tests from 0.317 to 0.781. Conclusion: Although the number of participants was limited (n = 40), the PAT seems to be a useful instrument for assessing ADL performance in older people living in residential homes. In general, internal consistency, test-retest reliability, and validity were satisfactory.

Rehearsal strategies during motor-sequence learning in old age: Execution vs motor imagery

Motor imagery and action-based rehearsal were compared during motor sequence-learning by young adults (M = 25 yr., SD = 3) and aged adults (M = 63 yr., SD = 7). General accuracy of aged adults was lower than that of young adults (F1,28 = 7.37, p = .01) even though working-memory capacity was equivalent in the two groups. Motor imagery and rehearsal by action increased accuracy in both age groups, compared with minimization of opportunity for rehearsal (F1,28 = 30.95, p < .001), but no interaction was found with age group, which suggests that young and aged adults were equally capable of motor imagery and action-based rehearsal. It was assumed that differences in performance between young and aged participants related to the formation of mental representations of sequences and integration of new elements into these representations rather than the capacity for motor imagery or rehearsal by action per se. The current study was exploratory and involved a relatively small sample of 15 participants per age group. Caution must be taken when considering the results.

Heiner Maier, Jutta Gampe, Bernard Jeune, Jean-Marie Robine, James W. Vaupel (eds): Supercentenarians . Springer, Dordrecht, 2010

Meslé et al. show that life expectancy at 110 years in France is close to 2 years and how it is difficult to estimate life expectancy and mortality rates at these ages. Jutta Gampe shows that mortality rates after 100 years of age do not increase with age but, rather, that they are close to 0.5. This conclusion is of the utmost importance, as Jim Vaupel and his colleagues forecast that median longevity could exceed 100 years in 2100 in developed countries [1– 4] ; however, they did not really study what could be the consequences regarding maximal longevity. Some years ago, Vallin and Caselli [5] published survival curves: with a life expectancy of 105 years, the oldest survivors would die at more than 140 years of age. By contrast, assuming mortality rates are close to 0.5, as shown by Jutta Gampe in her chapter, a simple computation shows that if one half of the approx. 800,000 persons of the 2007 French birth cohort reached 104 years of age, as expected by Christensen et al. [3] , there would be no survivor of this cohort beyond 122–123 years of age. This has provoked a debate on the value of mortality rates at very old ages. This debate is not futile because with the same median longevity of 105 years (if it were indeed possible), the maximal longevity could vary between ca. 120 and 140 years. The first value seems to be compatible with what has been observed for several decades, while the latter implies that we are far from approaching the limit of human life. One may regret that this book on supercentenarians did not go beyond the beginning of this debate on maximal longevity. Despite this imperfection, this book is an invaluable source of information on supercentenarians, as this information is sometimes distorted by wrong claims of superlongevity in countries often loaded with a less than perfect registration system. It shows that the time for knowing the exact maximal longevity of human beings has come and that the era of wrong claims is over. This is good news. Éric Le Bourg , Toulouse Heiner Maier, Jutta Gampe, Bernard Jeune, Jean-Marie Robine, James W. Vaupel (eds)