a section of the journal
Frontiers in Psychology10.3389/fpsyg.2020.599190No Detectable Electroencephalographic Activity After Clinical Declaration of Death Among Tibetan Buddhist Meditators in Apparent Tukdam, a Putative Postmortem Meditation StateDylan T. Lottdlott@wisc.edu011058Tenzin Yeshi010578N. Norchung010578Sonam Dolma010578Nyima Tsering010578Ngawang Jinpa010578Tenzin Woser010578Kunsang Dorjee010578Tenzin Desel010578Dan Fitch011058Anna J. Finley011058Robin Goldman011058Ana Maria Ortiz Bernal010589Rachele Ragazzi011058Karthik Aroor011058John Koger011058Andy Francis011058David M. Perlman011058Joseph Wielgosz011058David R. W. Bachhuber011058Tsewang Tamdin010578Tsetan Dorji Sadutshang010258John D. Dunne0110358Antoine LutzCenter for Health Minds, University of Wisconsin-Madison
,
Madison, WI
,
United StatesDelek Hospital
,
Gangchen Kyishong, Dharamshala, Himachal Pradesh
,
IndiaDepartment of East Asian Languages and Literature, University of Wisconsin-Madison
,
Madison, WI
,
United StatesDepartments of Psychology and Psychiatry, University of Wisconsin-Madison
,
Madison, WI
,
United StatesEdited by: Antonino Raffone, Sapienza University of Rome
,
ItalyLyon Neuroscience Research Centre, INSERM U1028, CNRS UMR5292, Lyon 1 University
,
Lyon
,
FranceMen-Tsee-Khang/TMAI
,
Upmuhal, Dharamshala, Himachal Pradesh
,
IndiaReviewed by: Marieke Karlijn Van Vugt, University of Groningen, Netherlands Jose L. Herrero, Feinstein Institute for Medical Research
,
United StatesSchool of Human Ecology, University of Wisconsin-Madison
,
Madison, WI
,
United Statesof the Center for Healthy Minds at the University of Wisconsin-Madison, research was
,
USA281202111141220202682020
Recent EEG studies on the early postmortem interval that suggest the persistence of electrophysiological coherence and connectivity in the brain of animals and humans reinforce the need for further investigation of the relationship between the brain's activity and the dying process. Neuroscience is now in a position to empirically evaluate the extended process of dying and, more specifically, to investigate the possibility of brain activity following the cessation of cardiac and respiratory function. Under the direction conducted in India on a postmortem Buddhist practitioners in which decomposition is putatively delayed. For all healthy baseline (HB) and postmortem (PM) subjects presented here, we collected resting state electroencephalographic data, mismatch negativity (MMN), and auditory brainstem response (ABR). In this study, we present HB data to demonstrate the feasibility of a sparse electrode EEG configuration to capture well-defined ERP waveforms from living subjects under very challenging field conditions. While living subjects displayed well-
defined MMN and ABR responses, no recognizable EEG waveforms were discernable
in any of the tukdam cases.
INTRODUCTION
Over the past several decades, a combination of groundbreaking
technological advances and increasingly sophisticated analytic
strategies have made it possible to deploy more nuanced
assessments of minimally conscious states in deeply comatose
and peri-mortem patients
(Wijnen et al., 2007; Kroeger et al.,
2013; Di Perri et al., 2014; Gosseries et al., 2014)
. These same
advances raise questions about conventional notions of personal
identity, compound ethical issues surrounding artificial life
support and organ donation, and increasingly complicate our
understanding of the boundary between life and death
(Lock,
1996, 2002a; Adams et al., 2009)
. Medical science has responded
to this complex landscape by parsing brain death into distinct
types, e.g., whole brain death, brainstem death
(Shewmon, 2001;
Lock, 2002a)
. Yet, such distinctions have become increasingly
difficult to maintain in the wake of advances which make it
possible to artificially prolong the body’s basic functions in
ever more complex circumstances
(Laureys, 2005; Staff and
Nash, 2017; Koenig and Kaplan, 2019)
. Some researchers have
suggested that equating “brain death†with death itself is
symptomatic of a wider cultural discourse that takes a reductive,
brain-centric approach to human life, personhood, and somatic
integrity
(Shewmon, 2001; Vidal, 2009)
. These tensions are
further exacerbated by the ways in which declarations of death
are interwoven with the demand for organs for transplant
(Lock,
2002b, 2016; Gardiner and Sparrow, 2010)
, a profit driven health
care system, and systemic problems of access, particularly for
people of color
(Aviv, 2018)
and communities already weakened
by economic devastation; realities brought into stark relief by the
current pandemic. Therefore, close and socio-culturally informed
examination of neural peri-mortem processes holds increasing
scientific, cultural, and ethical importance.
From the perspective of the neuroscience of consciousness,
recent EEG studies on the early postmortem interval reinforce
the need for further investigation of the relationship between
the brain’s activity and the dying process. Studies suggest the
persistence of electrophysiological coherence and connectivity in
the brains of rats for a period of time following induced fatal
cardiac arrest
(Borjigin et al., 2013)
, and the presence of high
amplitude slow wave EEG signals for up to 80 seconds following
their decapitation
(van Rijn et al., 2011)
. Studies in humans have
also shown evidence of surges in EEG and the bispectral index
(BIS) at or in the period following clinical death
(Chawla et al.,
2009; Auyong et al., 2010; Norton et al., 2017)
. Recently, research
using the mismatch negativity (MMN) paradigm suggests that the
auditory pathways may be responsive to stimuli in the moments
just prior to clinical death
(Blundon et al., 2020)
. Altogether, these
studies strongly suggest that death is not an event that occurs at a
single point in time.
While scientific research has primarily studied neural
processes in the immediate window surrounding clinical death,
many of the world’s religions and cultures have long held that
death is a process extended in time
(Tylor, 1958; Palgi and
Abramovitch, 1984; Boyer, 2007; Gennep, 2010)
. Neuroscience is
now in a position to empirically evaluate the extended process
of dying and more specifically, to investigate the possibility of
brain activity following the cessation of cardiac and respiratory
function. Whether this would also imply that there is some form
of subjective experience that persists beyond the cessation of
cardiorespiratory function is, at this time, merely a matter of
speculation. However, the possibility that brain activity—along
with the concomitant possibility of some level of consciousness—
persists in the period immediately following clinical death raises
a host of questions: are there factors or behaviors that effect
how long postmortem brain activity persists? How might we
objectively assess or demonstrate the presence of subjective
consciousness during that time or parse its chronometry? If it
becomes possible to demonstrate the persistence of some form of
brain activity that has previously been correlated with subjective
awareness, what form of ethics should guide how we relate to the
decedent body?
The Center for Healthy Minds at the University of
WisconsinMadison was invited to explore some of these questions in India
through research on a postmortem meditative state cultivated by
some Tibetan Buddhist practitioners. Tibetan Buddhists believe
that this state, known as tukdam (thugs dam), enables one to
achieve spiritual liberation by experiencing the fundamental
nature of mind that is said to be especially accessible at the time
of death, when the mind is believed to no longer register sensory
impressions or engage in conceptual elaboration. All humans are
said to have this opportunity, as it is believed to arise naturally
during the process of dying, but only advanced meditators are
thought to have the ability to apprehend and use that experience
for spiritual realization
(Lati Rinpoche et al., 1979; Dalai Lama
XIV and Hopkins, 2004; Chagme and Rinpoche, 2010; Tsenshap
et al., 2011)
. According to the tradition, this meditative state
mainfests externally as a delay in, or attenuation of, the processes
of postmortem decomposition. The visage of those in tukdam is
described as radiant, their skin remains supple and elastic, and
the area around the heart is said to be warmer than the rest of
the body. Individuals in tukdam “: : : can remain in this state for
a week or even a month according to their own wish : : : Even in
the hot season in India people have remained in [this meditative
state] for two weeks like someone asleep – no longer breathing,
like a corpse but, unlike a corpse, not smelling.â€
(Dalai Lama XIV,
2006:177-178)
. When the body starts to smell and signs of bodily
decomposition become apparent, it is understood that tukdam
has been released.
This Tukdam Project, developed in conversations between
Dr. Richard J. Davidson and His Holiness Tenzin Gyatso,
the XIV Dalai Lama, is a collaborative long-term empirical
research effort of the Center for Healthy Minds in partnership
with Men-Tsee-Khang (Sowa-Rigpa, Dharamsala, India), Delek
Hospital (Dharamsala, India), and the Office of His Holiness
the Dalai Lama. Informed by Tibetan Buddhist medical and
religious understandings of the death process, the project
combines ethnographic and psychophysiological research in an
attempt to understand the social and meditative practices that
Tibetan Buddhists believe provide the foundation for entering
tukdam. It also seeks to discover what neural or other biological
mechanisms may be involved in postmortem cases recognized
by Tibetan Buddhists as tukdam. We hypothesized that some
residual brain activity might persist in tukdam practitioners
communities, most of our practitioners were recruited through
relationships and contacts developed by Dylan Lott (DL) over
successive periods of fieldwork.
Between 2013 and 2018, we received notification of 13
postmortem tukdam cases from across India. Word of these cases
were directed either to the Office of His Holiness the Dalai Lama,
Dr. Tsetan Sadutshang (TS; Delek Hospital), or Dr. Tsewang
Tamdin (TT; Men-Tsee-Khang). Occasionally, DL or other team
members were notified first. In all cases, either TT or TS would
perform an initial phone interview to determine if the subject fit
our criteria (no history of neurological disease, no odor or other
signs of decomposition present, the body had not been preserved
in any way). If these criteria were met, TT (a Western-trained
medical doctor) and TS would examine the decedent in person—
or via digital images—to confirm that decomposition had not
set in prior to requesting permission for our research team to
observe and record. Given the distances and challenging travel
conditions within India, some cases required a day’s journey
before we could begin recording. Once there, we would conduct
initial observations and send digital images for visual inspection
by TT or TS who would make the decision whether to proceed
with data collection. In some cases, the teams were welcomed
to observe but ultimately not permitted to record data. In other
cases, the tukdam had concluded and decomposition begun by
the time we had reached the location.
Experimental Design
For all healthy baseline (HB) and postmortem (PM)
subjects presented here, we collected resting state
electroencephalographic data, MMN, and ABR. Recording
sessions in postmortem subjects were repeated twice daily, once
in the morning and once in the afternoon until decomposition
began or tukdam was deemed concluded.
For all subjects, medical records, meditation practice and life
history questionnaires were collected (from family members or
disciples in the case of PM). HB subjects were also queried about
their lucidity and level of awareness during the time of data
collection. Interviews and data collection sessions were, when
feasible, video recorded by the research team.
Recording Environments
As all data were recorded in field conditions, special note
must be made regarding the recording environments, which
varied greatly (see Tables 1, 2). Most tukdam subjects were
recorded in hospital or monastery quarters, with one tukdam case
recorded in a retreat area above Dharamsala. Living subjects were
for a period following clinical death and that this might be
a factor associated with the delay in decomposition which—
although culturally recognized—has not yet been confirmed
through objective measures. To detect such activity, we used
EEG to monitor the brain’s response to auditory stimuli. This
approach is supported by studies that show specific types of
auditory stimuli elicit well-defined electrical signals (event related
potentials) independent of conscious attention and in states of
minimal co
nsciousness (Näätänen et al., 2007
). For example,
MMN waveforms are discernable in patients in a vegetative state
and suggest the presence of some residual cognitive activity
(Boly
et al., 2011)
. Additionally, the auditory brainstem response (ABR)
has been used to determine the viability of the brainstem in cases
of coma and brain death
(Hall et al., 1985; Kaga et al., 1985;
Garcia-Larrea et al., 1987; Facco et al., 2002)
. In this report, we
present the initial findings of our continuing research on possible
EEG correlates of tukdam. To demonstrate that we are able to
collect quality data under challenging field conditions we also
present data collected from living practitioners during the course
of our research.
MATERIALS AND METHODSEthics and Recruitment
Our research received approval from the University of
Wisconsin’s Institutional Review Board and the Research
Ethics Committee of Men-Tsee-Khang. All Men-Tsee-Khang
Team members received Human Subjects Research training
as well as training in all data collection and study protocols.
Living subjects provided written consent after being informed
of the study goals and a demonstration of the equipment and
the procedures involved. Decedent subjects were enrolled in the
study with the consent of the eldest family member or disciple.
All participants (or their surrogates) were given the equivalent
of $25 in Indian Rupees for their participation. This amount
was determined as a culturally acceptable offering without
incentivizing participation.
We succeeded in enrolling 14 living practitioners and 13
tukdam subjects. All subjects presented without a history
of neurological disorder or hearing impairment beyond that
associated with aging. Recruitment to the study was complicated
by the fact that practitioners are very reserved and typically
secretive about their practice and accomplishments, as both
secrecy and humility are considered integral to sustaining
the mindset upon which higher states of realization depend.
Furthermore, monasteries and retreat communities in India are
often separated by long distances that are challenging to traverse.
To aid in recruitment, The Office of the His Holiness the Dalai
Lama sent letters to 28 nunneries and monasteries representing
the major Tibetan Buddhist denominations in India requesting
their cooperation and help in identifying potential candidates.
Team members did further outreach and demonstrations of
equipment at major monasteries, religious elder homes, and
community centers in Tibetan communities throughout India.
Though some healthy baseline (HB) subjects were recruited
following presentations in the Tibetan monastic and lay
HB1
HB2
HB3
HB4
HB5
F
M
M
M
M
Nun
Monk/retreatant
Monk/retreatant
Monk/retreatant
Lay Practitioner
Setting
Elder home
Room
Retreat area
Room
Monastery
recorded in monastery quarters, retreat areas above Dharamsala,
and elder homes. Table 1 presents data recorded from living
subjects to demonstrate that we were able to get quality data
under the same challenging conditions in which PM data
was collected; it is not intended to represent a control group
for the PM subjects themselves (see Discussion section). To
guarantee a stable, well-conditioned power supply under local
conditions, all data collection was done on battery power only.
Participants were positioned—when possible and with minimal
disturbance of the body—away from any conductive material
or electrical outlets. We used a digital EMF meter to optimize
the position of our equipment to ensure we recorded in areas
that minimized electrical noise while still preserving culturally
appropriate locations for the deceased. During data collection, all
electrical appliances (ceiling fans, heaters, lights) were turned off
and/or unplugged.
EEG Recording and Processing
All EEG data were collected and recorded using Biosemi’s
ActiveTwo R system via a Dell Latitude E6530 (Jan 2013–May
2019) or Dell Latitude 7490 (June 2019) laptop computer. Four
flat Ag/AgCl electrodes were placed on the scalp with adhesive
conducting gel after cleaning each site with an alcohol pad: Fz,
Cz, Pz, and T8. Biosemi’s common mode sense (CMS) and driven
right leg (DRL) electrodes were used to improve impedance and
reduce interference through reference to the AD-box output
(van Rijn et al., 1990)
. These active electrodes were placed at
C3 (CMS) and C4 (DRL) on the coronal plane of the scalp.
Right and left mastoids were used as reference. Bioplar EKG
leads were placed just beneath the midpoint of the right clavicle
and below the left floating rib. All electrodes were wrapped five
times by the CMS/DRL wire to provide further insulation of the
signal to the AD-box.
Data were recorded at a sampling rate of 16384Hz across all
phases of the protocol. Electrode impedances were monitored
using Biosemi’s Actiview R software. Auditory stimuli were played
from a WAV file on the study laptop and were delivered using
Etymotic ER-3 R pneumatic headphones tipped with foam inserts.
The transducer housings were attached by clips to the lapel of a
robe or shirt at a sufficient distance away from scalp electrodes
in order to minimize possible signal interference. Auditory levels
were tested for comfort and audibility with living subjects prior
to running the protocol; with decedent subjects, volume was set
loud enough to be heard faintly by the researcher standing two
feet distant. Each auditory stimulus was registered by a custom
designed digital trigger that permitted visual monitoring via
Actiview R of the stimuli during recording and precise epoching
based on stimulus onset during analysis.
Following a 5 to 10 min baseline data collection, MMN and
ABR tasks were administered. The MMN protocol was a roving
odd-ball paradigm similar to
Garrido et al. (2008)
with a duration
of 16 min and 40 s. Pure tones (70 ms) were presented every
500 ms and varied from 500-800 Hz in steps of 50 Hz, with
the same tone repeating from 1 to 11 times pseudorandomly.
There were a total of 2000 stimuli per session, 13% of which
were deviant. One of four roving odd-ball tone series were
randomly selected and presented during any given session to
reduce the likelihood of attenuated response via adaptation and
prediction in the event of multiple recording sessions
(Garrido
et al., 2009)
. The canonical finding with MMN is the increased
negative amplitude of the negative waveform found in response
to a rare deviant event presented among a set of standard stimuli.
This MMN occurs irrespective of a person’s direction of attention.
If the MMN was detectable postmortem, it would indicate some
residual cortical activity. MMN was followed by 30 s of silence,
which was in turn followed by the ABR protocol. This consisted of
a series of 4000 220 “click†events (white noise, 0.1 ms duration)
presented at 20 Hz (9 subjects) or jittered 17–21 Hz (3 subjects),
producing 20 “clicks†per second for 3 min and 20 s. ABR reflects
activity at the cochlear nucleus and in the brainstem. If the
ABR was detected postmortem, it would indicate some residual
brainstem activity postmortem.
EEG Analysis
Using a study specific interface written in MNE-Python
(Gramfort et al., 2013; Fitch et al., 2020)
, data were visually
inspected for artifacts with a notch filter at 50 Hz and a
highpass filter at 0.5 Hz, using the MNE filter defaults. Epochs
containing pulse or eye movement, gross movement, or which
were contaminated by higher frequency, higher amplitude noise
were manually rejected. For analysis, data were filtered with
MNE’s raw filter function defaults, using the default fir design
of “firwin.†MMN data were bandpass filtered from 1 Hz to
35 Hz, epoched between 100 ms and 400 ms from stimulus
onset, baseline corrected, and averaged separately for standard
and deviant trials. A difference waveform was calculated by
subtracting standard from deviant. The classic MMN difference
wave form is negative in the range of 100 to 300 ms
(Hall, 2007)
.
Our MMN wave form was quantified as the mean amplitude of
the difference waveform from 90 ms to 180 ms after stimulus
onset at Fz and Cz, following previous literature in expert
meditators
(Fucci et al., 2018)
. ABR data were bandpass filtered
from 100 Hz to 3000 Hz, epoched between 2 ms and 10 ms from
stimulus onset, baseline corrected, and averaged across all trials.
The ABR was quantified as the duration of the maximum positive
peak which typically occurs as a wave IV/V complex
(Hall, 2007)
between 4 and 8 ms, calculated as the time between when the
waveform first crossed zero before and after the peak. All MMN
and ABR data were weighted by the number of trials included
per subject.
Participants
Healthy Baseline Subjects
Healthy baseline EEG data were collected by the same teams
and in comparably challenging settings as expected for tukdam
subjects, for 14 subjects (monastic practitioner n = 10, lay
practitioner n = 1, lay non-practitioner n = 3). These recordings
are included here to demonstrate our ability to get quality data
under challenging field conditions identical to those in PM cases
and are not intended as a control group. Of these, 8 were excluded
either because of excessive noise, eye, or head movement and
one incomplete protocol (following a request to discontinue after
approximately 9 min). Additionally, one HB had a single noisy
electrode (Fz), which was excluded from analyses. Practitioners
were all seated and instructed to relax and not engage in any
specific type of meditation; all chose to close their eyes during
the recording. Of those presented in this paper, only one is
female (see Discussion section). Ages range from 61 to 86 years
(mean = 73.6) (Table 1).
Tukdam Subjects
Between 2013 and 2016, we were informed of 12 potential cases
of tukdam, of which the research team was permitted to record
five. Between 2017 and 2019, the team learned of 15 potential
tukdam cases, of which we were permitted to record eight. Thus,
PM EEG data were collected on 13 subjects in total (monastic
practitioner n = 11, lay non-practitioner n = 2). Of these, six
could not be included in this analysis owing to excessive electrical
interference or incomplete protocols. Ages range from 43 to
91 years (mean = 70.6) (Table 2). In this report, we present data
only from the recording session closest to the time of clinical
death. The earliest our teams were able to record was 26 h
postmortem, although 3 or 5 days were more common (see
Discussion section).
RESULTSMismatch Negativity
Figure 1 shows the averaged ERP responses for MMN (deviant
minus standard = difference) in HB and PM subjects. Data are
here shown for Fz and Cz, given the primary distribution area
of the MMN response
(Hall, 2007; Näätänen et al., 2007)
. In HB
subjects, a typical MMN wave form is seen. Using Welch’s t-test
on the mean amplitude of the difference waveform by group, Fz,
t(3.07) = 3.46, p < 0.039; for Cz, t(4.27) = 5.29, p < 0.005. The
mean difference for HB Fz = 0.71 mV (sd = 0.35 mV) and HB
Cz = 0.71 mV (sd = 0.28 mV). For PM Fz = 0.01 mV (sd = 0.05
mV) and PM Cz = 0.07 mV (sd = 0.07 mV). PM subjects (Figure 1
PM) have no discernible response. In HB subjects (Figure 1
HB), a negative deflection just after 100 ms is clearly visible.
Moreover, the sample size precluded any meaningful analysis by
age
(Pekkonen et al., 1993; Hall, 2007)
. Supplementary Figure 1
presents MMN data for HB and PM subjects individually.
Auditory Brainstem Response
Figure 2 shows the averaged ERP responses for ABR in HB and
PM subjects. In HB subjects, a typical ABR wave form is seen.
Using Welch’s t-test on the duration of maximum peak of the
wave IV/V complex at Fz, t(4.25) = 4.41, p < 0.010; for Cz,
t(5.09) = 3.23, p < 0.022. The mean difference for HB Fz = 3.24 ms
(sd = 1.25 ms) and HB Cz = 3.15 ms (sd = 1.41 ms). For PM
Fz = 0.47 ms (sd = 0.27 ms) and PM Cz = 0.77 ms (sd = 0.62 ms).
Data are here shown for Fz and Cz
(Hall, 2007)
. PM subjects
(Figure 2 PM) show no discernable waveform, while in HB
subjects (Figure 2 HB) wave V peaks at 7.5 ms. The relatively
low amplitude of the wave peaks in HB is consistent with models
based on age-related hearing loss and the limitations of our array
(Hall, 2007)
. Supplementary Figure 2 presents ABR data for HB
and PM subjects individually.
DISCUSSION
In this study, we demonstrated the feasibility that a sparse
electrode EEG configuration is capable of capturing well-defined
ERP waveforms from living subjects under very challenging
field conditions. We also presented EEG data on individuals
who were recognized by Tibetan lay, medical, and religious
specialists in India as being in the postmortem state called
tukdam. No recognizable EEG waveforms were discernable in
any of these tukdam cases, thus we failed to find support for
the hypothesis of residual brain activity following the cessation
of cardiorespiratory function in tukdam cases recorded beyond
26 h postmortem. While we did not expect to be able to assess
whether some form of awareness was present (as asserted in
the Tibetan Buddhist tradition), we had hypothesized that
residual brainstem activity could be a factor in the reported
delay of decomposition. This hypothesis was based on research
demonstrating the brainstem’s role in integrating the activity of
different organ systems of the body and regulating homeostasis
through the management of bodily energy and wastes
(Shewmon, 2001)
.
It is important to note that even if tukdam is mediated by
residual electrical activity in the brainstem, this activity may
generate signals that are too weak to be detected on the scalp
surface or not possible to resolve owing to the limitations of
our field equipment. If signal were detected, we would still need
other types of data to shed light on the possible mechanisms that
link brain activity and external signs of tukdam. Alternatively, if
activity (or in this case, lack of activity) in the brain postmortem
is not a mediator of the reported lack of decomposition,
other biological mechanisms could be responsible. In both
cases, we believe that—in addition to lifestyle, medical, and
FIGURE 2 | Comparison of averaged ABR wave forms for all Living Subjects (HB) and Postmortem Subjects (PM).
Frontiers in Psychology | www.frontiersin.org 6
practice history—collecting blood, saliva, and tissue to investigate
other potential mechanisms is key
(Hyde et al., 2013; Metcalf
et al., 2016)
. When such fluids and tissues become available,
discovery-based science with large-scale metabolomics and whole
epigenome arrays can be examined.
Challenges and Limitations
There are several limitations to this study, a number of which
result from the unique conditions in which the study must
be carried out and from the difficulty of operationalizing the
culturally salient signs of tukdam for research (e.g., smell, rate of
decomposition, and lasting suppleness of the skin).
Although we have done extensive outreach and the Dalai
Lama regularly speaks of the importance of scientific research
on tukdam in his public talks to the Tibetan community, timely
notification of tukdam events or of individuals nearing the time
of death continues to be difficult to obtain. As noted in Table 2,
the earliest we have been able to record data has been 26 h from
the time of death. In part, the delay is a consequence of the
typical Tibetan Buddhist practice of observing the deceased for
three days before determination can be made of tukdam. Other
factors, including the belief held by some Tibetans that touching
the body too soon following death will disturb the tukdam, also
played a role in delayed access to potential cases. In the future,
by establishing relationships with practitioners when they are still
alive, we hope to minimize the interval between the conventional
Western definition of death and the time we begin recording.
Ideally, we will seek to record practitioners—and lay persons not
expected to enter tukdam as a control group—as they are in the
process of dying and before the cardiorespiratory function has
completely ceased.
Other sources of data—such as blood, saliva, and gut biome—
would be important to collect as the study moves forward,
but which we were unable to do given certain cultural and
infrastructural challenges.
As we cannot predict when and if someone will enter tukdam,
we also remain focused on increasing the number of HB and
perimortem subjects who, based on their practice history, have
a greater likelihood of entering tukdam. A greater number of
practitioners will provide us with much needed control data and
lay the foundation for the acquisition of perimortem data. Such
data will enable us to examine possible predictors of entering
tukdam, something that has eluded practitioners for centuries.
Further, that we have but one female subject in each group (HB,
PM) reflects the broad cultural and religious challenges we have
had recruiting women to the study. Efforts to recruit female
practitioners are underway.
The datasets presented in this article are not readily available.
The protocol allows us to share data; however, each request must
be reviewed by the University of Wisconsin IRB beforehand.
Requests to access the datasets should be directed to RD;
rjdavids@wisc.edu.
ETHICS STATEMENT
The studies involving human participants were reviewed by
and received approval from the Institutional Review Board,
University of Wisconsin-Madison and the Research Ethics
Committee of Men-Tsee-Khang. The participants or their
surrogates provided their written informed consent to participate
in this study.
AUTHOR CONTRIBUTIONS
DL wrote the manuscript, managed the study, conducted
interviews and outreach, and collected and analyzed the data.
RD edited the manuscript and conceived of the research design,
methods, and analyses. AL conceived of the research and helped
design methods and experiments and analyses, and helped edit
the manuscript. JD helped edit the manuscript. TT and TS
helped with research design and implementation and oversaw
data collection in India. DB, DP, and JW contributed to the
research design and methods. KA and JK helped design the field
equipment, experimental procedures, and field analysis methods.
DP and JW also helped edit the manuscript. AB and RR helped
to process and analyze MMN and ABR data. RG, DF, and
AJF designed the analysis scripts, analysis methods, figures, and
statistical analyses and edited the manuscript. TY, NT, NN, SD,
NJ, TW, KD, and TD collected data and provided translation
and logistical support. All authors contributed to the article and
approved the submitted version.
FUNDING
Funding for this work was provided by donors to the Center for
Healthy Minds. None of the donors participated in any aspects of
the design, analysis, or write-up of this work.
ACKNOWLEDGMENTS
The authors would like to thank His Holiness The Fourteenth
Dalai Lama, Tenzin Gyatso (India); The Office of His Holiness
the Dalai Lama; Samdhong Rinpoche, The Abbots and Tibetan
Buddhist Monastic Communities in India; Mr. Tashi Tsering
Phuri (Men-Tsee-Khang, Director) and the doctors incharge
of MTK branch clinics in Mundgod, Bylakuppe, Hunsur, and
Kollegal; Men-Tsee-Khang Research Ethics Board;
Men-TseeKhang Research Team: Dr. Rigzin Sangmo (Men-Tsee-Khang,
Research Head), Dr. Lhundhup, Dr. Choepa, Dr. Yangzom
Dolkar (Delek), Lobsang Soepa, Dr. Tara, Dr. Jigme, Dr.
Lobsang Dhargay, Dr. Pema Gyaltsen, Dr. Karma Tenzin, Dr.
Sonam Dolkar Oshoe, Mr. Tsering Paljor, TD, Mrs. Lhadon
(Delek Hospital), and Mr. Tsetan Dorje (Men-Tsee-Khang). The
Center for Healthy Minds: Sonam Kindy, Enrique Guzman, Dr.
Yangbum Gyal, Nate Vack, Ty Christian.
SUPPLEMENTARY MATERIAL
The Supplementary Material for this article can be found
online at: https://www.frontiersin.org/articles/10.3389/fpsyg.
2020.599190/full#supplementary-material