Objective: 

Bright light therapy is known to improve cognitions and mood. Recently, transcranially administered bright light via ear canals (TBLE) has found to alleviate symptoms of SAD. Also, TBLE stimulation modulate neural networks of the human brain (Starck et al. 2012). We studied the effect of TBLE on cognitive performance and depressive symptoms in young healthy adults.

Methods: 

Forty one university students (age: 244 years) were randomized into TBLE and control (C) groups. During three week study, TBLE group received 12 min daily doses of TBLE. TBLE was produced using light emitting diodes. Recognition task (REC) (Cognispeed, Finland) measured temporal threshold for the recognition of masked character. The depressive symptoms were evaluated using Beck depression inventory.

Results: 

At baseline TBLE and C groups did not differ significantly in any measured parameters. After study period significant difference (p=0.018) was found between groups in attentional performance (REC). Recognition time decreased in TBLE and C groups 20ms and 3ms, respectively. Significant decrease (p=0.048) from 4.39 to 2.69 in BDI total score was found in TBLE group. Corresponding decrease in C group was from 4.76 to 4.52 (ns).

Conclusions: 

TBLE treatment improves attention performance in young healthy adults. A plausible mechanism for the faster recognition of characters in TBLE group could be linked to the earlier findings of increased power of low frequency fluctuations and functional connectivity increase in lateral visual and sensorimotor networks during single bout of TBLE. TBLE might alter phase-locking fluctuations in neuronal networks by affecting stochastic resonance and thus increase recognition capability (Velasquez & Dominquez 2007).

References: 

Starck,T., Nissilä,J., Aunio,A., Abou-Elseoud A.& Kiviniemi,V. 2012. WJNS 2:81–90, Velasquez,J.L.P & Dominquez,R.G.E. 2007. J Biol Phys 33:49–59