Frequent smartphone use could increase a person’s chances of having an enlarged median nerve and could lead to the impairment of pinch strength and hand function, revealed a new study.

Published in Muscle & Nerve, the study did not clearly link heavy smartphone use to carpal tunnel syndrome (CTS), Medscape.com reported.

“The exact clinical relevance of the study findings is not known. Future studies are warranted to address the clinical relevance of median nerve enlargement in high smartphone users,” said Esra Erkol Inal of Suleyman Demirel University, Turkey, who is the lead author of the study.

“Still, youngsters should be aware of the dangers of these pocket devices,” she said.

The researchers noted that smartphones compel users to type with their thumbs and engage in repetitive wrist flexion and extension – movements that are involved in carpal tunnel syndrome’s etio-pathophysiology.

Research indicates that students now usually spend more than three hours per day emailing, texting, and browsing the internet using their mobile phones.

The study included 102 university students. Among this group, 66 people used a single-hand-held smartphone, while the remaining 36 did not use a smartphone.

Using the Smartphone Addiction Scale (SAS), users were grouped as high users, low users, and nonusers.

The study showed that median nerve ratios were significantly higher among high smartphone users than they were in nonusers.

Although ultrasonography showed enlargement of the FPL tendons within all of the groups, the enlargement was the most dramatic among high smartphone users.

Moreover, the study showed that pinch strength were correlated with SAS scores. Thumb pain was also higher in those with higher SAS scores.

“But we think that duration of daily smartphone use is the most important factor affecting the median nerve, pinch strength, and hand function,” said Inal.