PeMSAA-UK Award for best published Research / Audit/ Quality Improvement Project in Sri Lanka
2021 PeMSAA-UK Academic Award for Research Winners (Undergraduate Category)



PeMSAA-UK is proud to announce the winners of the 2021 Academic Award for Research under “Undergraduate category.” The winners will receive the following

- PeMSAA-UK embossed personalised Plaque/s and Certificate/s

- A gift to the total value of £250.00 in cash

Herewith we are able to give a taster of their excellent work. You can access the full dissertation by clicking the link at the end of the abstract.


Winning submission:

EFFECT OF L-THEANINE ON SELECTIVE ATTENTION IN A TRAFFIC-RELATED REACTION TASK IN SLEEP-DEPRIVED YOUNG ADULTS: A DOUBLE-BLIND PLACEBO-CONTROLLED, CROSSOVER STUDY

Authors

Lead Investigator:

Umangi Karunaratne

Co-Investigators:

Dayathrie Karunarathne

Sumudu Karunaratne

Kavindya Gayathri

Wikum Karunathilake

Navakulan Karunyan

Sathya Kasuni

Hansi Kaushalya

Rumal Kiriwandala

Sandamal Manesha

Hridaya Kaflay


Abstract

Background: L-theanine is a non-protein-forming amino acid naturally found in tea leaves (Camelia sinensis). Limited evidence suggests that L-theanine improves attention. Sleep deprivation is known to impair attention, making psychomotor reactions delayed and more erratic, and potentially affecting the performance and safety of automobile driving.

Objectives: We aimed to determine whether L-theanine improves neuro-behavioural measures of selective attention in acutely sleep-deprived healthy adults in a traffic-based recognition reaction time task.

Methods: In a double-blind, placebo-controlled, counterbalanced, two-way crossover experiment we compared the effects of a single 200-mg dose of L-theanine with a placebo (150 ml of distilled water) on a traffic-scene-based visual recognition reaction time task, in 24 healthy volunteers aged 20-25 years (13 males), who were deprived of sleep the night before testing.

Their task was to respond to imminent traffic accident scenes presented on a computer screen as fast as possible by pressing a response button while ignoring safe scenes. They were tested pre-dose and 45 minutes post-dose, with each treatment administered one week apart. Number of hits (i.e. responses to imminent accident scenes) and false alarms (i.e. responses to safe scenes); and hit reaction time of the task were considered the main outcome measures.

Results: Eighty-eight percent of the test sessions showed 100% hit rate, and all sessions had a hit rate more than 90%. In pre-dose vs. post-dose comparison, hit rates were similar between two treatments. However, L-theanine significantly reduced the number of false alarms (p = 0.014), whereas placebo did not (p > 0.05). L-theanine reduced reaction time to imminent accident scenes by 38.65 ms (p = 0.007) and placebo by 19.08 ms (p = 0.016), thus L-theanine showing a 20-ms advantage over placebo.

Conclusions: Our results indicate L-theanine improves selective visual attention by increasing the speed of information processing and improving target-distractor discriminability in sleep-deprived healthy volunteers. It is consistent with functional magnetic resonance imaging changes

reported in previous studies, where equivalent doses of L-theanine were found to suppress cortical processing of distractors and reduce the activity of the default mode network of the brain (that is implicated in mind-wandering) during visual selective attention tasks. Recording of brain electrophysiology during the same visual attention task in future experiments will provide concurrent neurophysiological evidence for the attentional effects we observed with L-theanine.