Fractal temporal organisation of motricity is altered in major depression

Aybek, Selma; Ionescu, Anisoara; Berney, Alexandre; Chocron, Oury; Aminian, Kamiar; Vingerhoets, François

doi:10.1016/j.psychres.2012.03.047

Cited by 18 publications

(19 citation statements)

References 42 publications

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“…How activity correlations at small time scales (<~1–2 hours) are altered in mood disorders is still unclear. Three recent studies provided seemingly discrepant results 4 12 13 . The study of Krane-Gartiser et al .…”

Section: Discussionmentioning

confidence: 95%

“…Three recent studies provided seemingly discrepant results41213. The study of Krane-Gartiser et al .…”

Section: Discussionmentioning

confidence: 99%

“…Human motor activity displays seemingly irregular fluctuations over a wide range of time scales from seconds to hours 4 5 . In healthy young individuals these fluctuations are not random but possess robust temporal correlations that are similar at different time scales and independent of mean activity levels 6 7 .…”

mentioning

confidence: 99%

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Progression of Dementia Assessed by Temporal Correlations of Physical Activity: Results From a 3.5-Year, Longitudinal Randomized Controlled Trial

Lek

Patxot

et al. 2016

Sci Rep

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Cross-sectional studies show that activity fluctuations in healthy young adults possess robust temporal correlations that become altered with aging, and in dementia and depression. This study was designed to test whether or not within-subject changes of activity correlations (i) track the clinical progression of dementia, (ii) reflect the alterations of depression symptoms in patients with dementia, and (iii) can be manipulated by clinical interventions aimed at stabilizing circadian rhythmicity and improving sleep in dementia, namely timed bright light therapy and melatonin supplementation. We examined 144 patients with dementia (70–96 years old) who were assigned to daily treatment with bright light, bedtime melatonin, both or placebos only in a 3.5-year double-blinded randomized clinical trial. We found that activity correlations at temporal scales <~2 hours significantly decreased over time and that light treatment attenuated the decrease by ~73%. Moreover, the decrease of temporal activity correlations positively correlated with the degrees of cognitive decline and worsening of mood though the associations were relatively weak. These results suggest a mechanistic link between multiscale activity regulation and circadian/sleep function in dementia patients. Whether temporal activity patterns allow unobtrusive, long-term monitoring of dementia progression and mood changes is worth further investigation.

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Section: Discussionmentioning

confidence: 95%

“…Three recent studies provided seemingly discrepant results41213. The study of Krane-Gartiser et al .…”

Section: Discussionmentioning

confidence: 99%

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Progression of Dementia Assessed by Temporal Correlations of Physical Activity: Results From a 3.5-Year, Longitudinal Randomized Controlled Trial

Lek

Patxot

et al. 2016

Sci Rep

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“…The altered correlation patterns in the shift work animal might be a combined effect of removing animals from their home cages and scheduled shift work during inactive phase. In human studies, it has been shown that depressed people had disrupted fractal activity patterns [4,12]. It is possible that the stress associated with the transition to a new environment disrupted long-range activity correlations in these animals before they fully adapted to the environment.…”

Section: Lack Of Stable Baselinementioning

confidence: 99%

“…Outputs from a wide variety of physiological systems, such as heart rate and motor activity, exhibit complex fluctuation patterns characterized by fractal/ scale-invariant structures with properties that remain invariant over a wide range of timescales [1][2][3][4][5][6][7][8][9]. These fractal patterns appear to be a hallmark of healthy physiology because they are robust in healthy physiological systems but are significantly disrupted or abolished in degraded systems that are more vulnerable to catastrophic events and less adaptable to perturbations [2,4,10 -13].…”

Section: Introductionmentioning

confidence: 99%

Simulated shift work in rats perturbs multiscale regulation of locomotor activity

Hsieh

Escobar

Yugay

et al. 2014

J. R. Soc. Interface.

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Motor activity possesses a multiscale regulation that is characterized by fractal activity fluctuations with similar structure across a wide range of timescales spanning minutes to hours. Fractal activity patterns are disturbed in animals after ablating the master circadian pacemaker (suprachiasmatic nucleus, SCN) and in humans with SCN dysfunction as occurs with aging and in dementia, suggesting the crucial role of the circadian system in the multiscale activity regulation. We hypothesized that the normal synchronization between behavioural cycles and the SCN-generated circadian rhythms is required for multiscale activity regulation. To test the hypothesis, we studied activity fluctuations of rats in a simulated shift work protocol that was designed to force animals to be active during the habitual resting phase of the circadian/daily cycle. We found that these animals had gradually decreased mean activity level and reduced 24-h activity rhythm amplitude, indicating disturbed circadian and behavioural cycles. Moreover, these animals had disrupted fractal activity patterns as characterized by more random activity fluctuations at multiple timescales from 4 to 12 h. Intriguingly, these activity disturbances exacerbated when the shift work schedule lasted longer and persisted even in the normal days (without forced activity) following the shift work. The disrupted circadian and fractal patterns resemble those of SCN-lesioned animals and of human patients with dementia, suggesting a detrimental impact of shift work on multiscale activity regulation.

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