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Effect of Ramadan Fasting on Cognitive Functions Using P300 Event Related Potential and the Cancellation Test

Azizuddin Khan

ABSTRACT:
Muslims abstain from eating, drinking, sexual activity
from sunrise to sunset during the fasting month of
Ramadan. This study is aimed at investigating the
effect of Ramadan fasting on plasma glucose levels and
cognitive functions such as attention, memory, decision
making. The study was carried out with 15 healthy
adult participants. P300 recordings and plasma glucose
levels were taken from all participants in fasting and
subsequently non-fasting period as control group. The
cancellation test was also administered to assess
sustained attention in both periods. P300 was recorded
using auditory oddball paradigm which consisted of
120 standard and 40 target stimuli. Latencies and
amplitudes of P300 to target and standard stimuli were
analyzed. P300 wave is important component of
auditory event-related potentials (ERPs) commonly
used to examine cognitive function in decision making
processes. The biological drive to eat is linked to the
satiating power of food. Satiating power, or satiating
efficiency, describes the capacity of a food to suppress
and to inhibit further eating. Food causes this effect by
certain mediating processes that can be roughly
classified as sensory, cognitive, post-ingestive (preabsorptive)
and post-absorptive. These processes are
operated by the impact of food on physiological and
biochemical mechanisms, and collectively these
processes have been referred to as the satiety Free
eating is allowed from sunset to down. We investigated
cognitive changes linked to time of year and time of
day as a result of abstaining from routine physiologic
requirements.
Our experiments were carried out 16 healthy male
students (19.75±0.17) from Medical Faculty of Erciyes
University. All subjects were reported no neurological
or psychiatric problems and had normal hearing
sensitivity. They were from a similar ethnic
background, had no history of any systemic and
ocular disease and all were nonsmoking. All subjects
gave informed constant. All experiments were
performed according to the guidelines of the Erciyes
University Ethics Committee. Records were taken from
each students twice; once, during fasting (n=16), and
once when non- fasting condition (n=16). There was one
month between the measurements. Blood glucose levels
were also determined in each group. EEG activity was
recorded at the Fz, Cz, Pz and Oz electrode sites of the
International 10-20 system using Ag/AgCl electrodes,
affixed with electrode paste ad tape; with impedance of
10 k or less. Reference electrode was attached to the
right earlobe, and the ground electrode was attached to
the left earlobe. The signals were filtered with a bandpass
filter (0.03-100 Hz), and EEG was digitalized at
2000 Hz with a 1024 ms prestimulus baseline.
Waveforms were collected and averaged off-line by a
Pentium computer, which also controlled stimulus
presentation. Automatic artifact rejection was used,
based on signal amplitude (>50 V) or<50 V) in Fz.
Twenty responses to target stimuli were averaged at each
location.
In this study the glucose levels of the students during
Ramadan in fasting group is significantly lower when
compared to glucose levels after Ramadan in non-fasting
group which is parallel to the other research results in
literature. P300 latencies are decreased in all regions
during non-fasting when compared to fasting group
(p<0.05) in all regions. On the other hand there is an
increase in P300 amplitude in non-fasting group when
compared to fasting group in all regions but this increase
is only significant in Oz region (p<0.05).
The working hours and daily routine physical activities
of medical faculty students included in our study during
Ramadan were continued as before or after the Ramadan.
They didn’t take any medication or chemicals during,
before or after the Ramadan. Their sleeping hours were
decreased only 1 hour during Ramadan when compared
to normal period and their daily diet content didn’t
change during Ramadan fasting when compared to nonfasting
times. Only their meal times had changed. All the
records were taken at the same time of the day (15.00-
17.00) and only male students were included in the
study. In this study we elicited those long-term changes
in routine physiologic acquirements as not to eat and
drink for 12 hours period in Ramadan and rhythm
changes in routine sleeping habit may affect given
attention and memory