Stroke, Hemiplegic Shoulder Pain, Chronic Stroke Survivors
Conditions
Keywords
Focal vibration Therapy, stroke, pain, Hemiplegic Shoulder Pain
Brief summary
Hemiplegic Shoulder Pain (HSP) is a common and disabling complication after stroke, negatively affecting upper limb function, participation in rehabilitation, and quality of life. Despite the widespread use of conservative and physical therapies, evidence supporting the efficacy of specific non-invasive neuromodulation techniques remains limited. Focal Vibration Therapy (FVT) is a non-invasive physical modality that delivers localized mechanical vibration to targeted muscles or tendons and may modulate pain, muscle tone, and proprioception through frequency-dependent mechanisms. This randomized controlled trial aims to evaluate the efficacy of a multimodal FVT protocol, in addition to standard rehabilitation, compared with a sham intervention plus standard rehabilitation, in reducing pain in patients with chronic post-stroke Hemiplegic Shoulder Pain.
Detailed description
Hemiplegic Shoulder Pain (HSP) is a frequent and disabling sequela of stroke, with reported incidence rates ranging from 30% to 65% within the first six months after stroke onset. This variability reflects differences in diagnostic definitions and heterogeneity among studied populations. The underlying pathophysiology of HSP is multifactorial, involving musculoskeletal alterations (e.g., glenohumeral subluxation), abnormal nociceptive processing and central sensitization, and spasticity-related impairments, particularly affecting shoulder adductor and internal rotator muscles. HSP significantly interferes with post-stroke recovery by reducing upper limb motor performance and functional use, impairing participation in rehabilitation programs, and worsening quality of life. Although early and multidisciplinary management is recommended, available therapeutic approaches remain heterogeneous and include positioning strategies, manual therapy, pharmacological treatments, nerve blocks, botulinum toxin injections, dry needling, robotic-assisted therapy, and neuromodulation techniques. Physical therapeutic modalities are commonly used in rehabilitation settings due to their non-invasive nature and potential analgesic and functional benefits. However, evidence regarding their specific effectiveness in the treatment of HSP is inconsistent, and existing reviews often include heterogeneous interventions or focus on invasive approaches, leaving uncertainty about the role of targeted physical neuromodulation. Focal Vibration Therapy (FVT) is an emerging physical modality that applies localized mechano-sonic stimulation to muscle bellies or tendon insertions. Its effects are frequency-dependent and include modulation of nociceptive input through spinal gate control mechanisms at low-to-medium frequencies (approximately 35-50 Hz), modulation of muscle tone and proprioception through stimulation of Ia afferent fibers and induction of the tonic vibration reflex at intermediate frequencies (around 100 Hz), and modulation of deep pain perception through activation of Pacinian corpuscles at higher frequencies (approximately 200 Hz). Given the multifactorial nature of HSP and the limitations of current conservative treatments, there is a need to investigate structured intervention protocols integrating advanced physical modalities with standard rehabilitation. This randomized controlled trial will compare a multimodal FVT protocol, delivered in addition to standard rehabilitation, with a sham intervention plus standard rehabilitation in patients with chronic post-stroke HSP. The study will assess changes in pain intensity as the primary outcome, along with secondary outcomes related to shoulder function, range of motion, spasticity, quality of life, persistence of treatment effects, and safety of the intervention.
Interventions
DEVICEMultimodal Focal Vibration Therapy (FVT)
Participants in the experimental group will receive multimodal Focal Vibration Therapy (FVT) delivered using a medical vibration device, in addition to standard post-stroke shoulder rehabilitation. FVT will be applied to selected peri-scapular and shoulder muscles involved in pain generation and motor impairment, according to a standardized protocol. Each treatment session consists of two integrated phases. Physiokinesitherapy Phase (30 minutes): Participants will undergo a standardized rehabilitation protocol targeting recovery of the hemiplegic shoulder. Focal Vibration Therapy Phase (25 minutes): Four dome-shaped transducers will be applied directly to the skin over the muscle bellies of Pectoralis Major, Infraspinatus, Middle Deltoid, and Upper Trapezius. The device will deliver a pre-programmed sequence of vibrations consisting of: * 5 minutes at 35 Hz for superficial analgesia * 10 minutes at 100 Hz for muscle tone reduction * 10 minutes at 200 Hz for deep analgesia
All participants will undergo a standardized post-stroke shoulder rehabilitation program, including passive, active-assisted, and active exercises aimed at pain reduction, range of motion recovery, and functional improvement of the affected upper limb. Each session will consist of the same two phases as the experimental group. Physiokinesitherapy Phase (30 minutes): Identical to that administered in the experimental group. Sham Procedure Phase (25 minutes): Four transducers will be positioned on the same shoulder muscle sites as in the experimental group but connected to inactive outputs of the device, delivering no therapeutic vibration. To maintain participant blinding, an additional active transducer will be applied to a distant site, delivering perceptible vibration. Participants will be informed that the device acts through a systemic reflex stimulation mechanism. Device-related noise and tatactile stimulation on the contralateral limb will function as a sensory distractor.
Sponsors
University of Foggia
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
TREATMENT
Masking
DOUBLE (Subject, Outcomes Assessor)
Masking description
Participants and outcome assessors will be blinded to group allocation. Participants in both groups will undergo identical treatment sessions in terms of duration, setting, therapist interaction, and device application procedures. In the control group, the focal vibration device will be connected to inactive outputs while maintaining identical transducer placement and operational noise. To preserve participant blinding, an additional active transducer delivering perceptible vibration will be applied to a distant and clinically irrelevant site. Participants will be informed that the device operates through a systemic reflex stimulation mechanism, ensuring credibility of the sham procedure. Outcome assessors responsible for pain, functional, and biomechanical evaluations will not be involved in treatment administration and will remain unaware of group assignment throughout the study. Treating therapists administering the intervention will not be blinded.
Intervention model description
Parallel-group randomized controlled trial. Participants are randomly assigned in a 1:1 ratio to receive either active multimodal focal vibration therapy combined with standard physiokinesitherapy or sham focal vibration therapy combined with standard physiokinesitherapy. Both groups follow the same treatment schedule and duration.
Eligibility
Sex/Gender
ALL
Age
18 Years to 80 Years
Healthy volunteers
No
Inclusion criteria
* Age ≥ 18 years * Ischemic or hemorrhagic stroke confirmed by CT or MRI * Chronic post-stroke phase (≥ 6 months from event) * Presence of hemiplegic shoulder pain (NRS ≥ 4) * Preserved cognitive function sufficient to provide informed consent
Exclusion criteria
* Severe cognitive impairment or language deficits (e.g., severe aphasia) that prevent understanding of study procedures or reliable reporting of pain (e.g., inability to complete NRS or questionnaires). * Severe neglect, apraxia, or disorders of consciousness that interfere with participation in rehabilitation or outcome assessments. * Pre-existing shoulder pathology of the affected side unrelated to stroke (e.g., full-thickness rotator cuff tear, advanced glenohumeral osteoarthritis, inflammatory arthritis, prior shoulder surgery). * Fixed shoulder contractures or severe joint deformities limiting passive range of motion and preventing standardized assessment. * Botulinum toxin injections to shoulder upper limb muscles within the last 3-4 months prior to enrollment . * Current treatment with other experimental or non-conventional physical therapies for shoulder pain during the study period.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in Pain Intensity Assessed by Numerical Rating Scale (NRS) | From baseline (Day 0) to the Day 15 (end of treatment) | Change from baseline in pain intensity measured using the Numerical Rating Scale (NRS, 0-10) comparing multimodal Focal Vibration Therapy (FVT) plus standard rehabilitation versus standard rehabilitation plus sham procedure in patients with chronic post-stroke hemiplegic shoulder pain. Pain intensity will be assessed under three standardized conditions to reflect the multidimensional nature of hemiplegic shoulder pain: * Pain at rest (spontaneous pain) * Pain during passive range of motion (pROM) in shoulder flexion and abduction * Pain during active or active-assisted range of motion (aROM) The primary endpoint will be expressed as mean change (Δ score) between T0 and T1. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in Shoulder Function and Disability (SPADI) | Baseline (Day 0), Day 15 (end of treatment), and at 1, 3, and 6 months follow-up | Change from baseline in total score and subscale scores (Pain and Disability) of the Shoulder Pain and Disability Index (SPADI: range 0-100 where higher scores indicate greater pain and disability), comparing the two study groups across post-treatment and follow-up time points. |
| Change in Glenohumeral Range of Motion (ROM) (degrees) | Baseline (Day 0), Day 15 (end of treatment), and at 1, 3, and 6 months follow-up | Change from baseline in active and passive glenohumeral joint range of motion (ROM), including flexion, abduction, and external rotation, measured in degrees using a standardized universal goniometer. Higher values indicate improved joint mobility. |
| Change in Upper Limb Spasticity (Modified Ashworth Scale) | Baseline (Day 0), Day 15 (end of treatment), and at 1, 3, and 6 months follow-up | Change from baseline in muscle tone assessed by the Modified Ashworth Scale (MAS; range 0-4, where higher scores indicate greater spasticity) in shoulder internal rotators/adductors (Pectoralis Major, Subscapularis) |
| Change in Health-Related Quality of Life (SF-12) | Baseline (Day 0), Day 15 (end of treatment), and at 1, 3, and 6 months follow-up | Change from baseline in physical (PCS) and mental (MCS) health composite scores assessed using the Short Form-12 Health Survey (SF-12; higher scores indicate better health status). |
| Maintenance of Treatment Effect on Pain (NRS) at Follow-up | 1 month, 3 months, and 6 months after end of treatment | Between-group differences in pain intensity measured by the Numerical Rating Scale (NRS, 0-10) at 1, 3, and 6 months after completion of treatment, to assess persistence of treatment effects over time. |
| Incidence of Adverse Events (AEs) and Device-Related Adverse Events (ADEs) | From baseline through 6 months follow-up | Number and severity of adverse events (AEs) and device-related adverse events (ADEs) recorded during the study period. Events will be classified according to their relationship to the intervention. |
Countries
Italy
Outcome results
None listed