Time-Frequency Analysis of Motor Imagery During Plantar and Dorsal Flexion Movements Using a Low-Cost Ankle Exoskeleton

Sensor technology plays a fundamental role in neuro-motor rehabilitation by enabling precise movement analysis and control. This study explores the integration of brain–machine interfaces (BMIs) and wearable sensors to enhance motor recovery in individuals with neuro-motor impairments. Specifically,...

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Detalles Bibliográficos
Autores: Polo Hortigüela, Cristina, Ortiz, Mario, Soriano Segura, Paula, Iáñez, Eduardo, Azorín, José M.
Tipo de recurso: artículo
Fecha de publicación:2025
País:España
Institución:Universidad Miguel Hernández de Elche
Repositorio:REDIUMH. Depósito Digital de la UMH
OAI Identifier:oai:dnet:rediumh_____::0b5245a9ebb92be2e61764f48eb22ea5
Acceso en línea:https://hdl.handle.net/11000/39637
Access Level:acceso abierto
Palabra clave:electroencephalography (EEG)
brain–machine interface (BMI)
time-frequency transforms
motor imagery
low-cost exoskeleton
neurorehabilitation
inertial measurement units (IMUs)
CDU::6 - Ciencias aplicadas::62 - Ingeniería. Tecnología
CDU::6 - Ciencias aplicadas::61 - Medicina::612 - Fisiología
CDU::0 - Generalidades.::04 - Ciencia y tecnología de los ordenadores. Informática.
Descripción
Sumario:Sensor technology plays a fundamental role in neuro-motor rehabilitation by enabling precise movement analysis and control. This study explores the integration of brain–machine interfaces (BMIs) and wearable sensors to enhance motor recovery in individuals with neuro-motor impairments. Specifically, different time-frequency transforms are evaluated to analyze the correlation between electroencephalographic (EEG) activity and ankle position, measured by using inertial measurement units (IMUs). A low-cost ankle exoskeleton was designed to conduct the experimental trials. Six subjects performed plantar and dorsal flexion movements while the EEG and IMU signals were recorded. The correlation between brain activity and foot kinematics was analyzed using the Short-Time Fourier Transform (STFT), Stockwell (ST), Hilbert–Huang (HHT), and Chirplet (CT) methods. The 8–20 Hz frequency band exhibited the highest correlation values. For motor imagery classification, the STFT achieved the highest accuracy (92.9%) using an EEGNet-based classifier and a state-machine approach. This study presents a dual approach: the analysis of EEG-movement correlation in different cognitive states, and the systematic comparison of four time-frequency transforms for both correlation and classification performance. The results support the potential of combining EEG and IMU data for BMI applications and highlight the importance of cognitive state in motion analysis for accessible neurorehabilitation technologies.