Development of Kinematic Graphs of Median Nerve during Active Finger Motion: Implications of Smartphone Use

Time-varying changes in median nerve deformation and position in response to quantified pinch and grip forces

The ability of the median nerve (MN) to adapt in response to altered carpal tunnel conditions is important to mitigate compressive stress on the nerve. We assessed changes in MN deformation and position throughout the entire time course of hand force exertions. Fourteen right-handed participants ramped up force from 0% to 50% of maximal voluntary force (MVF) before ramping force back down in three different hand force exertion tasks (pulp pinch, chuck pinch, power grip). Pinch and grip forces were measured with a digital dynamometer, which were time synchronized with transverse carpal tunnel images obtained via ultrasound. Ultrasound images were extracted in 10% increments between 0% and 50% MVF while ramping force up (loading phase) and down (unloading phase). MN deformation and position relative to the flexor digitorum superficialis tendon of the long finger were assessed in concert. During loading, the nerve became more circular while displacing dorsally and ulnarly. These changes primarily occurred at the beginning of the hand force exertions while ramping force up from 0% to 20%, with very little change between 20% and 50% MVF. Interestingly, deformation and position changes during loading were not completely reversed during unloading while ramping force down. These findings indicate an initial reorganization of carpal tunnel structures. Mirrored changes in nerve deformation and position may also reflect strain-related characteristics of adjoining subsynovial connective tissue. Regardless, time-varying changes in nerve deformation and position appear to be an important accommodative mechanism in the healthy carpal tunnel in response to gripping and pinching tasks.

Wrist motion is distinct between touch screen and manual or digital devices

BACKGROUND

Restricted motion during touch screen device use may contribute to wrist overuse injuries. Wrist radioulnar deviation and extension while using touch screen devices and digital or manual counterparts in male and female medical professional dominant and non-dominant hands were quantified to test the hypothesis that mobile touch screen device use reduces wrist motion.

METHODS

An active motion detection system was used to record wrist motion of 12 participants while: tablet swiping and turning book pages; raising a cell and traditional phone to the ear; texting and typing; and entering numbers on a cell phone and manual calculator. Medial and lateral wrist surface range of motion (ROM) and minimum and maximum wrist radial-ulnar deviation and flexion-extension were quantified.

RESULTS

Device, sex and handedness effects were determined (P<0.05). Maximum medial radial deviation and ROM were greater using a cell versus traditional phone. Maximum medial radial deviation was higher in the nondominant wrist during backward tablet swiping and while backward page turning versus tablet swiping. Maximum and minimum medial extension angles and ROM were greater while typing versus texting. Female nondominant hand maximum lateral extension and ROM were greater for typing versus texting and maximum medial extension and lateral extension ROM greater during manual versus cell phone calculator use with handedness combined. Maximum lateral extension and ROM were greater in females versus males using manual calculators.

CONCLUSIONS

Sex and handedness should instruct touch screen, digital and manual device design and use for optimal performance and injury prevention.

Quantifying the Elasticity Properties of the Median Nerve during the Upper Limb Neurodynamic Test 1

Background

The upper limb neurodynamic test 1 (ULNT1) consists of a series of movements that are thought to detect an increase in neuromechanical sensitivity. In vivo, no trail was made to quantify the association between the nerve elasticity and different limb postures during ULNT1.

Objectives

(1) To investigate the relationship between nerve elasticity and limb postures during ULNT1 and (2) to investigate the intra- and interoperator reliabilities of shear wave elastography (SWE) in quantifying the elasticity of median nerve.

Methods

Twenty healthy subjects (mean age: 19.9 ± 1.4 years old) participated in this study. The median nerve was imaged during elbow extension in the following postures: (1) with neutral posture, (2) with wrist extension (WE), (3) with contralateral cervical flexion (CCF), and (4) with both WE and CCF. The intra- and interoperator reliabilities measured by two operators at NP and CCF+WE and intraclass correlation coefficients (ICCs) were calculated.

Results

The intraoperator (ICC = 0.72–0.75) and interoperator (ICC = 0.89–0.94) reliabilities for measuring the elasticity of the median nerve ranged from good to excellent. The mean shear modulus of the median nerve increased by 53.68% from NP to WE+CCF.

Conclusion

SWE is a reliable tool to quantify the elasticity of the median nerve. There was acute modulation in the elasticity of the median nerve during the ULNT1 when healthy participants reported substantial discomfort. Further studies need to focus on the elasticity properties of the median nerve in patients with peripheral neuropathic pain.

Association between smartphone use and carpal tunnel syndrome: A case-control study

Context

Carpal tunnel syndrome (CTS) is a common entrapment neuropathy of the upper limb. No published Saudi Arabian study has explored the effect of smartphones on the median nerve.

Aim

To assess the association between smartphone use and the development of CTS.

Settings and Design

This case-control study involved adults aged 18 years and older who visited King Khalid University Hospital (KKUH) in Riyadh, Saudi Arabia.

Materials and Methods

Patients were clinically diagnosed with CTS, and the diagnosis was confirmed by a nerve conduction study (NCS) and electromyography. The controls were free of CTS based on the disease-specific Boston Carpal Tunnel Questionnaire. Statistical analyses were performed using IBM-SPSS version 25.0.

Results

In total, 95 cases and 190 controls were included. Most of the participants were females (84.2%). The mean ages in the controls and cases were 34.6 +/- 10.2 years and 51.8 +/- 10.6 years, respectively. Using smartphones for 2 hours per day or more was significantly associated with the occurrence of CTS. After adjusting for covariates, 4 hours or more per day of smartphone use was associated with CTS. Moreover, those who held the smartphone with both hands had 7.8 times higher odds of developing CTS than those who held it with one hand.

Conclusion

CTS has a negative impact on patients' daily activities and work. This study showed that an increased number of hours of smartphone use is associated with the development of CTS. Further prospective studies are needed to examine the long-term effects of smartphone use.

High-resolution ultrasound demonstrates in vivo effects of wrist movement on the median nerve along the forearm

INTRODUCTION/AIMS

High-resolution ultrasound (HRUS) is the imaging method of choice to visualize peripheral nerve size, structure, and biomechanical performance. The purpose of this study was to show and quantify the effects of active and passive wrist alignment on median nerve (MN) cross-sectional area (CSA) along the forearm in a healthy population.

METHODS

Sixteen healthy volunteers underwent HRUS of their dominant forearm (n = 16, 10 males, 6 females, 18-55 y of age). Median nerve's CSA was assessed at four defined areas on the forearm in relation to active and passive wrist alignment.

RESULTS

Changes in wrist alignment were significantly associated with MN CSA (P < .001), regardless if the wrist was moved actively or passively. MN CSA was lowest during passive extension of the wrist joint and highest during passive flexion of the wrist joint (range: 4.5-23.2 mm² ).

DISCUSSION

The elasticity of nerve tissue, the loose connective tissue between the fascicles, and the paraneurium allow peripheral nerves to adapt to longitudinal strain. HRUS enables the demonstration of significant median nerve CSA changes along the forearm during active and passive wrist movement in healthy volunteers.

Relationship between Information and Communication Device Usage and Development of Hand Disorders

This study examined the association between hand disorders and time spent using information and communication devices. The participants in this study, conducted between January 2017 and 2020, were 150 healthy university students. They were tested for carpal tunnel syndrome and De Quervain’s tenosynovitis. Average daily device usage time was found to be 5.76 ± 3.00 (1.9-16.2) h. Smartphones were used the most, followed by personal computers and gaming consoles. However, usage time did not vary significantly by device type. Intensive users were significantly more likely to have De Quervain’s tenosynovitis (P < .001), while non-intensive users were significantly less likely to have hand disorders (P < .001) and less likely to have De Quervain’s tenosynovitis. These results can form the basis of guidelines for the prevention of information and communication device overuse.

Smartphone addiction and its complications related to health and daily activities among university students in Saudi Arabia: A multicenter study

Aim:

The aims of this study were to study the prevalence of smartphones addiction among college and university students in Kingdom of Saudi Arabia (KSA), and to determine the risk factors and complications associated with smartphone addiction.

Method:

This study was conducted in all provinces of KSA from December 2015 to June 2016 by sending questionnaire to student clubs of various universities through Survey Monkey. Questionnaire included (1) sociodemographics, (2) smartphone usage patterns and addiction behavior, (3) impact of smartphone usage on driving and medical complications, and (4) smartphone addiction scale.

Result:

The total number of participants was 1941 (response rate 80.9%) students representing most of the provinces of Saudi Arabia. The prevalence of smartphones addiction was 19.1%. Female participants were more addicted than male participants (P < 0.001). Smartphone addition was also significantly associated with musculoskeletal complication, upper limb, eyes and sleep complications.

Conclusion:

High frequent usage with prolonged duration of smartphone was associated with high risk to addiction. Furthermore, smartphone addiction had significant impact on performing daily activities, sleeping disorder, and health problems. Awareness about harm of smartphones addiction is required to provide to students and parents as well. Smartphones should not be given at younger age and it only be given when a child can differentiate its healthy and productive use from addiction.

Evaluating hand performance and strength in children with high rates of smartphone usage: an observational study

[Purpose] This study investigated the interaction effects between the levels of smartphone use and hand dominance on handgrip, pinch strengths, and functional hand performance in children. [Participants and Methods] A total of 60 children aged between 9 and 15 were assigned into two groups: Group A (high-frequency smartphone users) and Group B (low-frequency smartphone users). Use levels were determined according to the smartphone addiction scale-short version. A hand dynamometer and pinch gauge were used to measure handgrip and pinch strength respectively. Functions of the upper extremity and hand were scored using the Quick Disabilities of the Arm, Shoulder, and Hand questionnaire. [Results] Group A participants had reduced measurements in hand grip and pinch strength, especially in the dominant hand. However, Quick Disabilities of the Arm, Shoulder, and Hand scores indicated that hand function was decreased in the dominant hand whether the child was a high- or low-frequency smartphone user. [Conclusion] Results indicated that high levels of smartphone use diminished hand and pinch-grip strengths as well as and hand function. That is, hand and pinch-grip strengths were reduced in the dominant hands of high-frequency smartphone users. However, hand functions were affected in the dominant hands among both high and low-level smartphone users.

Morphological Changes of the Median Nerve Within the Carpal Tunnel During Various Finger and Wrist Positions: An Analysis of Intensive and Nonintensive Electronic Device Users

PURPOSE

To investigate the effects of static hand postures during various finger and wrist positions on morphological changes of the median nerve within the carpal tunnel in intensive and nonintensive electronic device users.

METHODS

Forty-eight university students, equally divided into intensive and nonintensive users (≥5 h/d and <5 h/d of electronic device usage, respectively), were randomly selected after questionnaire responses and evaluated clinically and by ultrasonography.

RESULTS

Intensive users reported more wrist/hand pain with a high severity score than nonintensive users. They also had larger median nerve cross-sectional areas, flattening ratios, and perimeters than nonintensive users, and showed less median nerve deformation under various finger and wrist positions. Compared with the neutral wrist position with all fingers extended for both intensive and nonintensive users, the cross-sectional areas decreased under finger flexion and grip, as well as wrist extension-flexion and radial-ulnar deviation. Overall, the average median nerve size of the dominant hand was much larger than that of the nondominant hand, especially for intensive users.

CONCLUSIONS

Wrist deviation from neutral can lead to more pronounced deformation of the median nerve than finger flexion for both intensive and nonintensive users. To minimize compression on the median nerve, it is important to keep the wrist as near to the neutral position as possible during computer-related work and avoid keeping the thumb and fingers in a static flexed position when using mobile devices, especially for single-hand use.

CLINICAL RELEVANCE

On the basis of this observational study, intensive users had enlarged and flattened median nerves as well as decreased nerve deformation during hand motions compared with nonintensive users. As overuse of electronic devices may adversely affect the median nerve, caution may be warranted.

The effect of smartphone usage on the upper extremity performance among Saudi Youth, KSA

The current study aims to investigate the effect of smartphone usage on the upper extremity performance among Saudi youth. A goniometer to measure the Range of Motion (ROM), the Smartphone Addiction Scale (SAS), McGill Pain scale and Chattanooga stabilizer were used to perform the current study on a sample of 300 university students from Al-Imam Mohammed Bin Saud University. The results have shown that smartphone addiction is negatively correlated to the elbow flexion, shoulder flexion, shoulder extension, shoulder abduction, shoulder adduction, and both shoulder internal and external rotation. Furthermore, the results have shown that McGill pain scores were positively correlated to elbow flexion, shoulder flexion, shoulder extension, shoulder abduction, shoulder adduction, and both shoulder internal and external rotation. The study has concluded that smartphone usage among Saudi youth negatively affects the upper extremity and causes a significant increase in the pain intensity. The study has recommended that there is an urgent need for a significant awareness campaign to warn the community regarding the impact of using smartphones for long periods of time.

Effects of electronic device overuse by university students in relation to clinical status and anatomical variations of the median nerve and transverse carpal ligament

INTRODUCTION

This study investigates the results of a questionnaire, provocative tests, and ultrasonographic measurements of carpal tunnel morphological parameters in intensive and nonintensive electronic device users.

METHODS

Forty-eight university students (equal numbers of intensive and nonintensive users, ≥5 h/day and <5 h/day of electronic device usage, respectively) were randomly selected after questionnaire responses were received and evaluated clinically and by ultrasonography. All participants were right-handed.

RESULTS

Intensive users had significantly more positive results in Phalen's and Durkan's tests and reported more wrist/hand pain compared with nonintensive users (P < 0.05). Intensive users also had significantly larger median nerve cross-sectional areas, flattening ratios, and perimeters as well as greater bowing of the transverse carpal ligament compared with nonintensive users (P < 0.05).

DISCUSSION

Overuse of electronic devices may adversely affect the median nerve within the carpal tunnel and the transverse carpal ligament, resulting in numbness, tingling, and pain in the hand. Caution may be warranted when using handheld electronic devices. Muscle Nerve 56: 873-880, 2017.