Neuropathic Pain, Catastrophizing, and Adherence in SAIS

The Relationship Between Neuropathic Pain, Pain Catastrophizing, and Adherence-Related Behavior in Subacromial Impingement Syndrome

Subacromial impingement syndrome is one of the most common causes of shoulder pain and may negatively affect daily activities and quality of life. While shoulder pain is usually considered nociceptive, some patients may also have a neuropathic pain component, which can influence symptom severity and treatment outcomes. In addition, psychological factors such as pain catastrophizing and adherence-related behavior may play an important role in recovery.

This prospective observational study aims to evaluate the presence of neuropathic pain in patients with subacromial impingement syndrome and to investigate its relationship with pain catastrophizing and adherence-related behavior. Patients undergoing a standard physical therapy program will be assessed at the beginning and after completion of treatment using validated clinical scales.

The findings of this study may help to better understand the interaction between pain characteristics, psychological factors, and adherence-related behavior, and contribute to the development of more individualized rehabilitation strategies

Study Overview

• Status: Recruiting
• Conditions: Subacromial Impingement Syndrome
• Intervention / Treatment: Other: Standard Conservative Physical Therapy

Detailed Description

Subacromial impingement syndrome (SIS) is one of the most common causes of shoulder pain and represents a substantial proportion of rotator cuff-related shoulder disorders. Although it is traditionally associated with nociceptive and mechanical pain mechanisms, recent evidence suggests that a subset of patients may also present with a neuropathic pain component and central sensitization, which may contribute to increased pain intensity, functional impairment, and poorer treatment outcomes.

In addition to biological factors, psychosocial variables play a critical role in chronic musculoskeletal pain. Pain catastrophizing, reflecting exaggerated negative cognitive and emotional responses to pain, has been associated with increased disability and delayed recovery. Similarly, adherence-related behavior may influence clinical outcomes, particularly in the context of physical therapy and exercise-based interventions. Understanding the interaction between neuropathic pain, catastrophizing, and adherence-related behavior may help identify clinically relevant subgroups and guide individualized rehabilitation strategies.

This study is designed as a prospective observational cohort study conducted in patients diagnosed with subacromial impingement syndrome who are referred to an outpatient physical therapy and rehabilitation clinic. Participants who meet the inclusion criteria will be consecutively enrolled and will receive a standard conservative physical therapy program. No additional or experimental interventions will be applied within the scope of the study.

Clinical and patient-reported outcome measures will be used to assess pain characteristics, psychological factors, functional status, and adherence-related behavior.

The primary aim of the study is to evaluate the relationship between neuropathic pain and pain catastrophizing in patients with subacromial impingement syndrome. Secondary analyses will explore the associations between these variables and adherence-related behavior, as well as clinical outcomes such as pain intensity and functional status.

The findings of this study are expected to contribute to a better understanding of the multidimensional nature of shoulder pain and to support the development of more targeted and individualized rehabilitation approaches.

• Study Type: Observational
• Enrollment (Estimated): 75

Contacts and Locations

• Study Contact: Name: Yakup ERDEN, MD; Phone Number: +905556692721; Email: yakuperden@hotmail.com

Study Locations

• Turkey (Türkiye)
  • Bolu, Turkey (Türkiye), 14020
    • Recruiting
    • AIBU Izzet Baysak Physical Treatment and Rehabilitation Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

• Sampling Method: Non-Probability Sample

Study Population

The study population consists of adult patients aged 18-65 years diagnosed with unilateral subacromial impingement syndrome who are referred to an outpatient physical therapy and rehabilitation clinic. Patients with symptoms lasting at least three months. Participants scheduled to undergo a standard conservative physical therapy program will be included.

Description

Inclusion Criteria:

• Unilateral subacromial impingement syndrome lasting at least 3 months
• Planned to start a 10-session physical therapy program
• Willing and able to provide informed consent

Exclusion Criteria:

• Upper extremity entrapment neuropathy or polyneuropathy
• History of diabetes mellitus
• Inflammatory rheumatic disease, infection, or malignancy
• Frozen shoulder
• History of shoulder fracture, dislocation, or surgery
• Complete rotator cuff tear on magnetic resonance imaging
• Calcific tendinitis
• Shoulder steroid injection or physical therapy within the previous 3 months
• Use of medication for neuropathic pain
• Pregnancy
• Cognitive impairment preventing completion of questionnaires

Study Plan

How is the study designed?

Number of groups / cohorts

1

Cohorts and Interventions

Group / Cohort	Intervention / Treatment
Patients with Subacromial Impingement Syndrome; Adults diagnosed with subacromial impingement syndrome who are scheduled to receive a standard conservative physical therapy program and are evaluated for neuropathic pain, pain catastrophizing, and treatment adherence.	Other: Standard Conservative Physical Therapy; Participants receive a standard conservative physical therapy program as part of routine clinical care. No experimental or study-assigned intervention is applied within the scope of this study.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Neuropathic Pain Component (DN4)	Neuropathic pain will be assessed using the Douleur Neuropathique 4 Questions (DN4). Total scores range from 0 to 10, with higher scores indicating a greater neuropathic pain component. A score of ≥4 will be considered indicative of neuropathic pain	Baseline and 2 weeks
Pain Catastrophizing (PCS)	Pain catastrophizing will be assessed using the Pain Catastrophizing Scale. Total scores range from 0 to 52, with higher scores indicating greater catastrophizing.	Baseline and 2 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pain Intensity at Rest (VAS)	Pain intensity at rest will be assessed using the Visual Analog Scale (VAS). Scores range from 0 to 10, with higher scores indicating greater pain intensity.	Baseline and 2 weeks
Pain Intensity During Activity (VAS)	Pain intensity during activity will be assessed using the Visual Analog Scale (VAS). Scores range from 0 to 10, with higher scores indicating greater pain intensity.	Baseline and 2 weeks
Pain Intensity at Night (VAS)	Night pain intensity will be assessed using the Visual Analog Scale (VAS). Scores range from 0 to 10, with higher scores indicating greater pain intensity.	Baseline and 2 weeks
Functional Status (DASH)	Functional status will be assessed using the Disabilities of the Arm, Shoulder and Hand (DASH) questionnaire. Scores range from 0 to 100, with higher scores indicating greater disability.	Baseline and 2 weeks
Anxiety and Depression (HADS)	Anxiety and depression will be assessed using the Hospital Anxiety and Depression Scale (HADS), which includes two subscales (HADS-A and HADS-D). Higher scores indicate greater symptom severity.	Baseline and 2 weeks
Adherence-Related Behavior (MMAS)	Adherence-related behavior will be assessed using the Morisky Medication Adherence Scale (MMAS), a self-reported measure originally developed to evaluate medication adherence. Although primarily designed for medication adherence, it will be used in this study as an indicator of general adherence-related behavior. Higher scores indicate better adherence-related behavior.	Baseline

Collaborators and Investigators

• Sponsor: Abant Izzet Baysal University
• Investigators: Principal Investigator: Yakup ERDEN, MD, Clinic of Physical Medicine and Rehabilitation, İzzet Baysal Physical Treatment and Rehabilitation Training and Research Hospital

Publications and helpful links

General Publications

• Ko S, Choi C, Kim S, Chae S, Choi W, Kwon J. Prevalence and Risk Factors of Neuropathic Pain in Patients with a Rotator Cuff Tear. Pain Physician. 2018 Mar;21(2):E173-E180.
• Vogel M, Binnebose M, Wallis H, Lohmann CH, Junne F, Berth A, Riediger C. The Unhappy Shoulder: A Conceptual Review of the Psychosomatics of Shoulder Pain. J Clin Med. 2022 Sep 19;11(18):5490. doi: 10.3390/jcm11185490.
• Ucar M, Cebicci MA, Koca I, Arik HO. Frequency of neuropathic pain in patients with shoulder pain. Eur Rev Med Pharmacol Sci. 2022 Aug;26(15):5422-5425. doi: 10.26355/eurrev_202208_29410.

Study record dates

Study Major Dates

• Study Start (Actual): April 2, 2026
• Primary Completion (Estimated): August 1, 2026
• Study Completion (Estimated): August 1, 2026

Study Registration Dates

• First Submitted: March 28, 2026
• First Submitted That Met QC Criteria: March 28, 2026
• First Posted (Actual): April 3, 2026

Study Record Updates

• Last Update Posted (Actual): April 8, 2026
• Last Update Submitted That Met QC Criteria: April 2, 2026
• Last Verified: March 1, 2026

More Information

Terms related to this study

• Keywords: Subacromial Impingement Syndrome; Shoulder Pain; Pain Catastrophizing; Neuropathic Pain; Adherence-related behavior
• Additional Relevant MeSH Terms: Shoulder Injuries; Pain; Neurologic Manifestations; Musculoskeletal Diseases; Nervous System Diseases; Wounds and Injuries; Neuromuscular Diseases; Joint Diseases; Peripheral Nervous System Diseases; Arthralgia; Pathological Conditions, Signs and Symptoms; Signs and Symptoms; Neuralgia; Shoulder Pain; Shoulder Impingement Syndrome
• Other Study ID Numbers: AIBU-FTR-YE-02

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO
• IPD Plan Description: Individual participant data will not be shared due to institutional policies and ethical considerations regarding patient confidentiality.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No