Document Type : Research articles


1 Sina Trauma and Surgery Research Center, Tehran University of Medical Sciences (TUMS), Tehran, Iran

2 Department of Occupational Health, School of Public Health, Shahroud University of Medical Sciences, Shahroud, Iran

3 Department of Community Medicine, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran

4 Department of Ergonomics, School of Health, Safety and Environment, Shahid Beheshti University of Medical Sciences, Tehran, Iran

5 Department of Occupational Health Engineering, School of Public Health, Iran University of Medical Sciences, Tehran, Iran

6 Department of Basic Sciences in Rehabilitation, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran

7 Department of Epidemiology and Biostatistics, School of Public Health, Shahroud University of Medical Sciences, Shahroud, Iran

8 Soheil Saadat, Sina Hospital, Hassan-Abad Square, Imam Khomeini Ave, Tehran, Iran.


Background: Background: Conversation over the cell phone while driving is a known risk factor for road traffic crash. Using hands-free to talk on the cell phone may remove visual and manual distraction yet not the cognitive distraction.
Objectives: The purpose of this study was to better understand the mechanisms of cognitive distraction due to hands-free cellphone conversation (HFPC) while driving.
Methods: Twelve male and 12 female University students in Tehran, Iran, were selected via the consecutive convenient samplingmethod, and randomly assigned to one of the following administrations of cross-over quasi-experimental study design, during year
2016: Administration 1, participants performed the tests while involved in HFPC, took rest for 60 minute, and then performed thetests another time without HFPC; Administration 2, participants performed the tests without HFPC, took rest, and then performedthe tests another time with HFPC. Each participant moved to the other administration after 7 to 10 days. The Vienna test system (VTS)was used to measure simple and choice reaction time, selective attention, visual orientation, and visual memory. Linear regressionanalysis was used to study the change in test scores due to HFPC.
Results: The mean age of participants was 27.1 ± 5.3 years. A history of road traffic crash (regardless of severity) was reported among9 (37.5%) participants in the previous year. Hands-free cell phone conversation while driving was directly associated with mean time
correct rejection score (P < 0.01) (selective attention), omitted response (P < 0.01) and median reaction time (P < 0.01) (choicereaction time), and mean reaction time (P < 0.01) (Simple reaction time). Moreover, HPFC was inversely associated with sum hits (P= 0.05) (selective attention), incorrect (P < 0.02) and correct response (P < 0.01) (choice reaction time), score based on viewing andworking time (P < 0. 01) (visual orientation), and visual memory performance (P < 0.01).
Conclusions: Using hands-free devices to converse during driving, impaired reaction time, selective attention, visual orientationand visual memory, which are essential for safe driving. Thus, the use of these devices does not preclude cognitive distraction andshould be restricted