On multifractals: A non-linear study of actigraphy data

  title={On multifractals: A non-linear study of actigraphy data},
  author={Lucas Gabriel Souza Francca and Pedro Montoya and Jos{\'e} Garcia Vivas Miranda},
  journal={Physica A-statistical Mechanics and Its Applications},
Abstract The healthcare process generates a vast quantity of data. Exploitation and analysis of such material might lead discoveries and potentially improve the clinical activity. Over the last years, several studies focused on the non-linear features exhibited by physiological signals and medical data. In general, the complex features of these signals have been demonstrated in some studies, ranging from heartbeat time intervals to neuron spikes series. Some works employed fractal and… Expand

Figures and Tables from this paper

Assessment of Fractal Characteristics of Locomotor Activity of Geriatric In-Patients With Alzheimer’s Dementia
Actigraphic signal characteristics and especially their (deviations from) fractal scaling may be a useful tool for aiding diagnosis, characterization, and monitoring of dementia, however, results may, besides contextual aspects, also substantially depend on specific methodological choices. Expand
Fractal and Multifractal Properties of Electrographic Recordings of Human Brain Activity: Toward Its Use as a Signal Feature for Machine Learning in Clinical Applications
Some of the practical challenges of applying fractal geometry to brain dynamics—and as a putative feature for machine learning applications, are highlighted and solutions to enable its wider use in neuroscience are proposed. Expand


Identifying Multifractality Structure on Postural Sway
The degree of multifractality extracted from the data is revealed, and the application of this computational technique attempts to describe the multiple strategies utilized by the motor control in response to static, yet swaying, human body posture. Expand
PhysioBank, PhysioToolkit, and PhysioNet: components of a new research resource for complex physiologic signals.
The newly inaugurated Research Resource for Complex Physiologic Signals, which was created under the auspices of the National Center for Research Resources, is intended to stimulate current research and new investigations in the study of cardiovascular and other complex biomedical signals. Expand
Statistical physics and physiology: monofractal and multifractal approaches.
This work focuses on interbeat interval variability as an important quantity to help elucidate possibly non-homeostatic physiologic variability because (i) the heart rate is under direct neuroautonomic control, and (ii) analysis of these heart rate dynamics may provide important practical diagnostic and prognostic information not obtainable with current approaches. Expand
Multifractality in human heartbeat dynamics
This work reports oneidence for multifractality in a biological dynamical system, the healthy human heartbeat, and shows that the multifractal character and nonlinear properties of the healthy heart rate are encoded in the Fourier phases. Expand
Quantification of scaling exponents and crossover phenomena in nonstationary heartbeat time series.
A new method--detrended fluctuation analysis (DFA)--for quantifying this correlation property in non-stationary physiological time series is described and application of this technique shows evidence for a crossover phenomenon associated with a change in short and long-range scaling exponents. Expand
The role of actigraphy in sleep medicine.
The validity, reliability and limitations of actigraphy for documenting sleep-wake patterns have been addressed and the use of computer scoring algorithms without controlling for potential artifacts can lead to inaccurate and misleading results. Expand
Nonlinear analysis of EEG signals at different mental states
The results show that EEG to become less complex relative to the normal state with a confidence level of more than 85% due to stimulation, which suggests that when the subjects are under sound or reflexologic stimuli, the number of parallel functional processes active in the brain is less and the brain goes to a more relaxed state. Expand
Altered Functional Performance in Patients with Fibromyalgia
The data revealed that both gait and balance were severely impaired in FM, and that subjective complaints associated with FM could contribute to functional disability in these patients, suggesting that optimal rehabilitation and fall prevention in fibromyalgia require a comprehensive assessment. Expand
Actigraphy validation with insomnia.
Actigraphy proved to be a satisfactory objective measure of sleep on 4 of 5 sleep parameters, but these results are specific to this particular instrument using this particular algorithm and should not be construed as a blanket endorsement of actigraphy for measuring insomnia. Expand
Use of actigraphy for monitoring sleep and activity levels in patients with fibromyalgia and depression.
Actigraphy is a useful means of studying activity levels and sleep patterns in fibromyalgia patients and demonstrated significant differences between FM patients with and without comorbid depression. Expand