Cortical Changes After Upper Limb Immobilization Measured by Electroencephalography

Effects of Upper Limb Immobilization on Sensorimotor Cortical Activity and Function Measured by EEG: A Prospective Observational Study

This study aims to investigate how temporary immobilization of the upper limb after injury affects brain activity and functional recovery.

Participants with fractures or soft tissue injuries of the upper limb who require immobilization will be evaluated at three time points: at the beginning of immobilization, after removal of the immobilization, and four weeks later.

Brain activity will be measured using electroencephalography (EEG), a non-invasive and painless technique that records electrical signals from the scalp. Functional outcomes such as pain, mobility, strength, and daily activity performance will also be assessed using validated questionnaires and clinical tests.

The purpose of this study is to better understand how immobilization influences the brain and physical recovery, in order to improve rehabilitation strategies for patients with upper limb injuries.

Participation is voluntary, and all participants will provide written informed consent.

Upper limb immobilization is commonly required after fractures and soft tissue injuries to promote healing. However, prolonged immobilization can lead to muscle weakness, sensory deficits, and changes in brain activity related to motor control.

Previous research has shown that even short periods of limb disuse can induce neuroplastic changes in the sensorimotor cortex. These changes may contribute to persistent functional limitations after immobilization is removed.

This prospective observational study aims to describe and quantify changes in sensorimotor cortical activity and functional outcomes associated with clinical immobilization of the upper limb.

Adult patients requiring immobilization for upper limb fractures or soft tissue injuries will be recruited. Eligible participants will be evaluated at three time points: baseline (within five days of immobilization), post-immobilization (within 24-48 hours after removal), and follow-up (four weeks after post-immobilization).

Brain activity will be recorded using a portable wireless electroencephalography (EEG) system following the international 10-20 electrode placement system. Resting-state and task-related recordings will be obtained. Spectral power in standard frequency bands and functional connectivity measures will be analyzed.

Clinical and functional outcomes will include patient-reported questionnaires (PRWE, QuickDASH, MHQ, SPADI, TSK-11, PCS), range of motion, grip strength, and joint position sense.

Statistical analyses will focus on longitudinal changes across time points using repeated-measures analysis of variance or mixed-effects models, depending on data distribution. Effect sizes and confidence intervals will be reported.

This study has been approved by the local ethics committee, and all participants will provide written informed consent prior to participation.

The results are expected to contribute to a better understanding of brain plasticity during immobilization and support the development of more effective rehabilitation strategies.

Inclusion Criteria:

• Adults aged 18 years or older.
• Radiologically confirmed upper limb fracture (distal radius, proximal humerus, metacarpals, phalanges, or carpal bones) or soft tissue injury (e.g., tendinopathy, triangular fibrocartilage complex injury).
• Requirement of orthopedic immobilization of the wrist/hand extending to the proximal two-thirds of the forearm for a minimum of 2 weeks and a maximum of 8 weeks.
• Ability to understand study procedures and follow instructions.
• Provision of written informed consent.

Exclusion Criteria:

• History of neurological disorders (e.g., stroke, epilepsy, traumatic brain injury).
• Current use of psychoactive or anticonvulsant medication.
• Bilateral upper limb injuries.
• Wrist fractures requiring elbow immobilization.
• Previous upper limb fracture or instability within the last 2 years.
• Cognitive impairment preventing adequate participation.