Neuropathic Characteristics of Subacromial Pain Syndrome

Hyperalgesia is defined as an exaggerated pain response to a painful stimulus that is disproportionate to the intensity of the stimulus. It is one of the pain descriptors assessed in the painDETECT questionnaire, which evaluates neuropathic pain features.It is one of the 7 questions in the painDETECT scale that evaluates neuropathic pain and is scored on a 6-point Likert scale and receives a score between 0-5.

Pain severity will be assessed using the Visual Analog Scale (VAS). VAS is a 10 cm horizontal line with endpoints labeled "no pain" (0) and "worst imaginable pain" (10). Patients will mark a point on the line that best represents their current level of shoulder pain.

Neuropathic pain features will be assessed using the painDETECT questionnaire, which consists of 9 items. Two items evaluate pain pattern and radiation, and seven items assess descriptors such as burning, tingling, mechanical allodynia, paroxysmal pain, thermal hyperalgesia, numbness, and pressure-induced pain (hyperalgesia). Each descriptor is rated on a 0-5 scale. The total score helps determine the likelihood of neuropathic pain.

Central sensitization will be evaluated using the Central Sensitization Inventory (CSI), which includes 25 items scored from 0 (never) to 4 (always). A score of 40 or more suggests a high probability of central sensitization (81% sensitivity, 75% specificity).

It will be evaluated with the shoulder pain and disability index (SPADI-Shoulder Pain and Disability Index). SPADI is a questionnaire with a total of 13 questions developed to measure disability associated with shoulder pain. In the subgroup of the questionnaire assessing pain, the patient is asked to rate the severity of pain during different activities in the past week by giving a score between zero (no pain) and 10 (most severe pain). In the sub-group assessing disability, the patient is asked to rate how much difficulty he/she has had during different activities in the last week by giving a score between zero (no difficulty at all) and 10 (receiving assistance). A score of zero indicates maximum well-being and a score of 130 indicates maximum ill health. The validity and reliability of the Turkish version of SPADI has been demonstrated.

Active and passive shoulder range of motion (ROM) will be measured using a goniometer. The movements evaluated include flexion, extension, abduction, adduction, internal and external rotation.