NORMAL SENSORY RESPONSE DURING UPPER LIMB NEURODYNAMIC TEST 1 WITH AND WITHOUT CERVICAL CONTRALATERAL FLEXION: A CROSS-SECTIONAL STUDY

B. Bonomi^1,2, S. Ballerini¹, A.B. Schmid³, C. Cescon¹, D. Corbetta^4,5, M. Barbero¹

¹University of Applied Sciences and Arts of Southern Switzerland, Department of Business Economics, Health and Social Care, Rehabilitation Research Laboratory 2rLab, Manno, Switzerland, ²Vita-Salute San Raffaele University, Master of Science in Rehabilitation Sciences, Milan, Italy, ³University of Oxford, Nuffield Department of Clinical Neurosciences, Oxford, United Kingdom, ⁴Universita Vita-Salute San Raffaele, Physiotherapy Degree Course, Milano, Italy, ⁵IRCCS Ospedale San Raffaele, Rehabilitation and Functional Recovery Department, Milan, Italy

Background: Upper Limb Neurodynamic Test 1 (ULNT1) is usually performed in patients with painful disorders of the upper quadrant to assess the mechanosensitivity of the peripheral nervous system. Even though some information about the sensory responses elicited during ULNT1 is available in healthy individuals, how these change with sensitizing manoeuvres such as cervical contralateral flexion (CCF) remains unclear.

Purpose: The main purpose of the study was to compare the ULNT1 sensory response with and without CCF in healthy volunteers.

Methods: The study was approved by the Local Ethics Committee (Rif. CE 4066) and all subjects gave informed written consent. Twenty-four healthy volunteers were invited to a single testing session at the Department of Business Economics, Health, and Social Care (DEASS) at the University of Applied Sciences and Arts of Southern Switzerland (SUPSI). ULNT1 was performed twice by the same examiner on each upper limb: once with and once without CCF in a randomized way. After each ULNT1, participants completed the following procedures: a pain drawing using a body chart on a digital tablet, an assessment of pain intensity using a numerical rating scale, and an evaluation of the pain quality using a list of predefined descriptors. A dedicated software analyzed each pain drawing and extracted pain extent (expressed as the percentage of the total body chart area) and pain location. The paired-samples Wilcoxon's test was performed to compare pain extent and pain intensity during ULNT1 with and without CCF. Additionally, differences in pain location were investigated by calculating the Jaccard Similarity Index, and pain quality changes using absolute and relative frequencies of the different descriptors.

Results: The mean difference of pain extent between the ULNT1 performed with and without CCF (left = 0.19% ± 0.58%; right = 0.17% ± 0.65%) was not statistically significant (p-value = 0.47). Jaccard Similarity Index values (left = 0.57 ± 0.24; right = 0.51 ± 0.24) suggested that the pain drawings of ULNT1 with and without CCF are comparable in terms of pain location. Pain intensity with ULNT1 with CCF (left = 6.25 ± 1.65; right 6.42 ± 1.67) was significantly higher (p-value > 0.05) than without CCF (left= 5.08 ± 1.67; right = 5.58 ± 1.77). ULNT1 with CCF was associated with a higher frequency of tingling, numbness and burning and a lower frequency of stretch than the ULNT1 without CCF.

Conclusions: Overall, the addition of CCF does not influence pain extent and pain location of the ULNT1 sensory response, but it significantly increases pain intensity. CCF during ULNT1 reduces the frequency of stretch sensation but increases sensations of burning, tingling and numbness which are typical neural sensations.

Implications: Our findings support the use of pain intensity changes with CCF in the interpretation of structural differentiation upon ULNT1 testing. Future work in patients will show whether the increase in neural sensations such as burning, tingling and numbness may further inform ULNT1 interpretation.

Funding acknowledgements: n/a

Keywords:
Neurodynamic test
Upper limb
Neural mechanosensitivity

Topics:
Pain & pain management
Musculoskeletal
Musculoskeletal: spine

Did this work require ethics approval? Yes

Institution: Dipartimento della sanità e della socialità

Committee: Comitato etico cantonale

Ethics number: Project ID: 022-00770; Rif. CE 4099