Persistent fluctuations in stride intervals under fractal auditory stimulation

Copyright @ 2014 Marmelat et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Stride sequences of healthy gait are characterized by persistent long-range correlations, which become anti-persistent in the presence of an isochronous metronome. The latter phenomenon is of particular interest because auditory cueing is generally considered to reduce stride variability and may hence be beneficial for stabilizing gait. Complex systems tend to match their correlation structure when synchronizing. In gait training, can one capitalize on this tendency by using a fractal metronome rather than an isochronous one? We examined whether auditory cues with fractal variations in inter-beat intervals yield similar fractal inter-stride interval variability as isochronous auditory cueing in two complementary experiments. In Experiment 1, participants walked on a treadmill while being paced by either an isochronous or a fractal metronome with different variation strengths between beats in order to test whether participants managed to synchronize with a fractal metronome and to determine the necessary amount of variability for participants to switch from anti-persistent to persistent inter-stride intervals. Participants did synchronize with the metronome despite its fractal randomness. The corresponding coefficient of variation of inter-beat intervals was fixed in Experiment 2, in which participants walked on a treadmill while being paced by non-isochronous metronomes with different scaling exponents. As expected, inter-stride intervals showed persistent correlations similar to self-paced walking only when cueing contained persistent correlations. Our results open up a new window to optimize rhythmic auditory cueing for gait stabilization by integrating fractal fluctuations in the inter-beat intervals.Commission of the European Community and the Netherlands Organisation for Scientific Research

Humour processing in frontotemporal lobar degeneration: A behavioural and neuroanatomical analysis.

Humour is a complex cognitive and emotional construct that is vulnerable in neurodegenerative diseases, notably the frontotemporal lobar degenerations. However, humour processing in these diseases has been little studied. Here we assessed humour processing in patients with behavioural variant frontotemporal dementia (n = 22, mean age 67 years, four female) and semantic dementia (n = 11, mean age 67 years, five female) relative to healthy individuals (n = 21, mean age 66 years, 11 female), using a joint cognitive and neuroanatomical approach. We created a novel neuropsychological test requiring a decision about the humorous intent of nonverbal cartoons, in which we manipulated orthogonally humour content and familiarity of depicted scenarios. Structural neuroanatomical correlates of humour detection were assessed using voxel-based morphometry. Assessing performance in a signal detection framework and after adjusting for standard measures of cognitive function, both patient groups showed impaired accuracy of humour detection in familiar and novel scenarios relative to healthy older controls (p < .001). Patient groups showed similar overall performance profiles; however the behavioural variant frontotemporal dementia group alone showed a significant advantage for detection of humour in familiar relative to novel scenarios (p = .045), suggesting that the behavioural variant syndrome may lead to particular difficulty decoding novel situations for humour, while semantic dementia produces a more general deficit of humour detection that extends to stock comedic situations. Humour detection accuracy was associated with grey matter volume in a distributed network including temporo-parietal junctional and anterior superior temporal cortices, with predominantly left-sided correlates of processing humour in familiar scenarios and right-sided correlates of processing novel humour. The findings quantify deficits of core cognitive operations underpinning humour processing in frontotemporal lobar degenerations and suggest a candidate brain substrate in cortical hub regions processing incongruity and semantic associations. Humour is a promising candidate tool with which to assess complex social signal processing in neurodegenerative disease

Efficacy of Musical Interventions in Dementia: Methodological Requirements of Nonpharmacological Trials

The management of patients with Alzheimer\u27s disease is a significant public health problem given the limited effectiveness of pharmacological therapies combined with iatrogenic effects of drug treatments in dementia. Consequently, the development of nondrug care, such as musical interventions, has become a necessity. The experimental rigor of studies in this area, however, is often lacking. It is therefore difficult to determine the impact of musical interventions on patients with dementia. As part of a series of studies, we carried out randomized controlled trials to compare the effectiveness of musical activities to other pleasant activities on various functions in patients with severe Alzheimer\u27s disease. The data obtained in these trials are discussed in light of the methodological constraints and requirements specific to these clinical studies. Although the results demonstrate the power of music on the emotional and behavioral status of patients, they also suggest that other pleasant activities (e.g., cooking) are also effective, leaving open the question about the specific benefits of music in patients with dementia. All these findings highlight the promising potential for nonpharmacological treatments to improve the well-being of patients living in residential care and to reduce caregiver burden

Recognition of facial and musical emotions in Parkinson's disease

International audienceBackground and purpose: Patients with amygdala lesions were found to be impaired in recognizing the fear emotion both from face and from music. In patients with Parkinson's disease (PD), impairment in recognition of emotions from facial expressions was reported for disgust, fear, sadness and anger, but no studies had yet investigated this population for the recognition of emotions from both face and music. Methods: The ability to recognize basic universal emotions (fear, happiness and sadness) from both face and music was investigated in 24 medicated patients with PD and 24 healthy controls. The patient group was tested for language (verbal fluency tasks), memory (digit and spatial span), executive functions (Similarities and Picture Completion subtests of the WAIS III, Brixton and Stroop tests), visual attention (Bells test), and fulfilled self-assessment tests for anxiety and depression. Results: Results showed that the PD group was significantly impaired for recognition of both fear and sadness emotions from facial expressions, whereas their performance in recognition of emotions from musical excerpts was not different from that of the control group. The scores of fear and sadness recognition from faces were neither correlated to scores in tests for executive and cognitive functions, nor to scores in self-assessment scales. Conclusion: We attributed the observed dissociation to the modality (visual vs. auditory) of presentation and to the ecological value of the musical stimuli that we used. We discuss the relevance of our findings for the care of patients with PD

Efficacy of Musical Interventions in Dementia: Evidence from a Randomized Controlled Trial

Although musical interventions have recently gained popularity as a non-pharmacological treatment in dementia, there is still insufficient evidence of their effectiveness. To investigate this issue, a single-center randomized controlled trial was conducted with forty-eight patients with Alzheimer\u27s disease or mixed dementia to compare the effects of music versus cooking interventions in the emotional, cognitive, and behavioral domain, as well as on professional caregiver distress. Each intervention lasted four weeks (two one-hour sessions a week). Multi-component evaluations (with blind assessors) were conducted before, during, and after the interventions to assess their short and long-term effects (up to four weeks post interventions). Analyses revealed that both music and cooking interventions led to positive changes in the patients\u27 emotional state and decreased the severity of their behavioral disorders, as well as reduced caregiver distress. However, no benefit on the cognitive status of the patients was seen. While results did not demonstrate a specific benefit of music on any of the considered measures, the present study suggests the efficacy of two pleasant non-pharmacological treatments in patients with moderate to severe dementia. Our findings highlight the potential of such interventions in improving the well-being of patients living in residential care, as well as reducing caregiver distress