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Vestibular Function and Depersonalization/Derealization Symptoms

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Abstract

Patients with an acquired sensory dysfunction may experience symptoms of detachment from self or from the environment, which are related primarily to nonspecific symptoms of common mental disorders and secondarily, to the specific sensory dysfunction. This is consistent with the proposal that sensory dysfunction could provoke distress and a discrepancy between the multi-sensory frame given by experience and the actual perception. Both vestibular stimuli and vestibular dysfunction can underlie unreal experiences. Vestibular afferents provide a frame of reference (linear and angular head acceleration) within which spatial information from other senses is interpreted. This paper reviews evidence that symptoms of depersonalization/derealization associated with vestibular dysfunction are a consequence of a sensory mismatch between disordered vestibular input and other sensory signals of orientation.
Multisensory Research (2015) DOI:10.1163/22134808-00002480 brill.com/msr
Vestibular Function and Depersonalization/Derealization
Symptoms
Kathrine Jáuregui Renaud
Unidad de Investigación Médica en Otoneurología, Instituto Mexicano del Seguro Social,
Av. Cuauhtémoc 330, Colonia Doctores, CP 06720, México D.F.
Received 2 October 2014; accepted 16 February 2015
Abstract
Patients with an acquired sensory dysfunction may experience symptoms of detachment from self
or from the environment, which are related primarily to nonspecific symptoms of common mental
disorders and secondarily, to the specific sensory dysfunction. This is consistent with the proposal
that sensory dysfunction could provoke distress and a discrepancy between the multi-sensory frame
given by experience and the actual perception. Both vestibular stimuli and vestibular dysfunction can
underlie unreal experiences. Vestibular afferents provide a frame of reference (linear and angular head
acceleration) within which spatial information from other senses is interpreted. This paper reviews
evidence that symptoms of depersonalization/derealization associated with vestibular dysfunction are
a consequence of a sensory mismatch between disordered vestibular input and other sensory signals
of orientation.
Keywords
Vestibular, depersonalization, derealization
1. Introduction
To produce a unified, coherent representation of the outside world, the inte-
gration of information from different sensory systems is essential. This paper
reviews evidence on the perception of unreality as a consequence of sensory
dysfunction, particularly dysfunction of the vestibular system.
A summary on spatial orientation and body representation is provided, with
concepts on the perception of unreality, to augment the literature available
on the relationship between sensory deficits and symptoms of depersonaliza-
tion/derealization.
*E-mail: kathrine.jauregui@imss.gob.mx
©Koninklijke Brill NV, Leiden, 2015 DOI:10.1163/22134808-00002480
2K. Jáuregui Renaud / Multisensory Research (2015)
2. Spatial Orientation
The vestibular system is the main sensory organ that transduces head orienta-
tion in space. Since graviceptors are primarily required for the perception of
the upright, vestibular afferents provide a frame of reference within which
spatial information from other senses may be interpreted. Accordingly, to
facilitate locomotion, head acceleration and velocity signals are centrally rep-
resented in a network that is organized within space coordinates and provides
a common reference for multisensory integration (Hess, 2001).
Patients with vestibular disease may experience illusions of self-movement
or movement of the environment and false perceptions of orientation (Bender,
1965; Clément et al., 2009; Page and Gresty, 1985). Similar experiences of
‘spatial disorientation’ are encountered in the aerospace environment (Adams
et al., 2014; Poisson and Miller, 2014), particularly when unusual motion chal-
lenges the vestibular system’s ability to transduce orientation so that the pilot
misperceives the motion of his aircraft (Benson, 1973).
Disorientation in flight not only compromises the pilot’s control of his air-
craft, but may also result in experiences of derealization, termed the ‘break-off
phenomenon’ (Benson, 1973; Clark and Graybiel, 1957; Sours, 1965). Apart
from disorders in the aviator’s perception of attitude and motion of the aircraft,
derealization incidents may vary from altered perception of the orientation of
the aviator’s body with respect to the aircraft or the surface of the earth, to feel-
ings of detachment and isolation, usually when flying straight and level at an
altitude of more than 30 000 ft (9150 m), in conditions where the horizon is ill
defined and there is a relative constancy in the aviator’s sensory environment
(Benson, 1973).
During spaceflight, adaptive changes in how the brain integrates vestibular
signals with other sensory information can lead to spatial disorientation, im-
paired movement coordination, vertigo, and perceptual illusions after return to
earth (Clément and Wood, 2014). The disorientation phenomena may be ex-
plained by the existence of an internal estimation of the gravitational vertical.
In microgravity it is still maintained, but incorrectly updated. The otolith or-
gans signal both head translation and head tilt relative to gravity, the stimulus
profile and concurrent afferents allow discrimination between the two types
of movement (Angelaki and Dickman, 2003). During adaptation to weight-
lessness, the sensory feedback anticipated by each movement is not consistent
with the information given by the otolith organs. The nervous system reinter-
prets these signals to represent fore–aft or left–right linear acceleration, rather
than pitch or roll of the head with respect to the vertical plane (Young et al.,
1984). This, in turn, leads to illusions, and probably also facilitates space mo-
tion sickness (Glasauer and Mittelstaedt, 1998). Although a fully adequate
theory of motion sickness is not presently available, it is recognized that when-
Multisensory Research (2015) DOI:10.1163/22134808-00002480 3
ever there are deviations or variations from a 1G background force of the earth,
motion sickness may result because of the disruption of vestibulo-ocular, op-
tokinetic, and colic reflexes (Lackner, 2014).
3. Body Representation
The pursuit of behavioral goals requires an integrated neural representation of
the body and of the space around the body (Popper and Eccles, 1977). Among
the diverse conceptions of body representation, Head and Holmes (1911) pro-
vided the classic description of different ‘schemata’ representing the body,
including the postural schemata containing a continuously updated represen-
tation of current body posture. In this context, body posture can be defined as
the orientation of the body and its parts with respect to the earth-vertical (grav-
itational vertical), whereas position designates the orientation of the body parts
to each other (Mittelstaedt, 1998).
The brain generates a coherent spatial representation of the body as a whole,
the body parts, and the body as related to the external world by integrating mul-
tisensory signals. Although representation of the body and, to some extent,
the environment is constructed from visual information through inspection
(Critchley, 1950), proprioceptive information is combined with visual, tactile
and motor feedback signals to represent the body (Maravita et al., 2003). Pri-
mary and secondary somatosensory cortex activity can be modulated by spatial
and tactile attention and by visual cues (Tamè et al., 2012; Taylor-Clarke et
al., 2002). The orientation of the visual world and the head is mainly per-
ceived through vision and the vestibular system, and the posture of the trunk is
mainly perceived through sense organs in the trunk itself (Mittelstaedt, 1998).
However, there is no single brain area responsible either for maintaining a rep-
resentation of the body or of space. Rather they are the result of a network of
interacting cortical and subcortical centers (Holmes and Spence, 2004). Ab-
normalities in the sensory cortex and areas responsible for an integrated body
representation are consistent with the proposal that the inferior parietal cor-
tex is concerned with spatial orientation, visuo-motor and vestibular function
(Brandt and Dieterich, 1999; Simeon et al., 2000).
The concept of bodily self-consciousness consists of several aspects, in-
cluding self-location, first-person perspective, self-identification and sense of
agency (for review, see Pfeiffer et al., 2014). Evidence suggests that unam-
biguous self-location and egocentric visuospatial perspective are related to
neural activity at the temporo-parietal junction (Blanke et al., 2005). Changes
in bodily self-consciousness depend on visual gravitational signals and the ex-
perienced direction of the first person perspective depends on the integration
of visual, vestibular, and tactile signals, as well as on individual differences in
idiosyncratic visuo-vestibular strategies (Pfeiffer et al., 2013). Vestibular pro-
4K. Jáuregui Renaud / Multisensory Research (2015)
cessing may serve as a spatial reference for the spatial determinants of bodily
self-consciousness (Lopez et al., 2012; Pfeiffer et al., 2013), coding for em-
bodiment and body ownership (Lopez et al., 2008). It also has an influence on
the registration of somatosensory input onto a map of the body, but no influ-
ence on the stored knowledge about the spatial organization of the body as a
physical object (Ferrè et al., 2013).
Seeing one’s body in extra-personal space (autoscopic phenomena) is an
illusory own body perception that affects the entire body and leads to abnor-
malities in embodiment as well as body ownership. There are three main forms
of autoscopic phenomena: autoscopic hallucinations (Maillard et al., 2004),
out-of-body experiences (Blanke et al., 2004) and heautoscopy (Brugger et
al., 1994). Autoscopic hallucinations may be due to a visuo-somatosensory
deficit, not associated with major deficits in bodily self-consciousness. Out-
of-body experiences and heautoscopy are frequently associated with patho-
logical sensations of position, movement and perceived completeness of one’s
own body, including vestibular sensations, visual body-part illusions and the
experience of seeing one’s body only partially (Blanke et al., 2004, 2005).
Evidence suggests that disturbed vestibular processing may play a key role
in triggering out-of-body experiences (Schwabe and Blanke, 2008), while the
abnormal bodily self-consciousness during heautoscopy may be caused by a
breakdown of self–other discrimination regarding affective somatosensory ex-
perience (Heydrich and Blanke, 2013).
4. The Perception of Unreality
Altered perceptions of the self and the environment are termed ‘dissociation
phenomena’. Dissociative experiences are common in the general population,
they may decline with age, but they are not related to socio-economic status,
sex, education, religion, or place of birth (Lambert et al., 2001a; Ross et al.,
1991). Depersonalization refers to experiences of unreality, detachment, or
being an outside observer with respect to one’s thoughts, feelings, sensations,
body or actions, while derealization refers to experiences of unreality or de-
tachment with respect to the surrounding (American Psychiatric Association,
2013).
Depersonalization/derealization symptoms may occur on a continuum
of circumstances, from healthy individuals under certain situational condi-
tions to neurological and psychiatric disorders (Bancaud et al., 1994; Cas-
sano et al., 1989; Coons, 1998; Lambert et al., 2002). Also, depersonal-
ization/derealization experiences are common under life-threatening stress
(Bernat et al., 1998). A community questionnaire survey study in the United
States of America reported prevalence rates of 19.1% for depersonaliza-
tion, 14.4% for derealization and 23.4% for either dissociative experience
Multisensory Research (2015) DOI:10.1163/22134808-00002480 5
(Aderibigbe et al., 2001). However, when the symptoms become recurrent or
persistent the diagnosis of depersonalization/derealization disorder has to be
considered.
Depersonalization/derealization disorder is a dissociative disorder during
which the patient feels as though he or she is detached from the self or from
the environment (American Psychiatric Association, 2013). In circa one third
of the patients, the disorder is episodic, and each episode may last hours,
days, weeks or even months (Baker et al., 2003; Simeon, 2004). The most
common, immediate precipitants of the disorder are severe stress, depression,
panic, marijuana and hallucinogen ingestion (Simeon, 2004). Mood, anxiety
and personality disorders are often comorbid with depersonalization disorder.
However, a functional magnetic resonance imaging (fMRI) study has shown
evidence of separate brain systems for each trait while performing tasks of
facial emotion processing, and its correlation with self-report scales of soma-
tization, depression, dissociation and anxiety (Lemche et al., 2013). The main
differences between patients with depersonalization disorder and control sub-
jects were:
for somatization in the right temporal operculum and ventral striatum,
for symptoms of depression in the right pulvinar and left amygdala,
for dissociation in the left mesial inferior temporal gyrus and left supra-
marginal gyrus,
for state anxiety in the left inferior frontal gyrus and para-hippocampal
gyrus, and
for trait anxiety, in the right caudate head and left superior temporal gyrus.
Phenomenological overlaps with the unawareness of ownership of one’s
body parts (asomatognosia) suggest that depersonalization might result from
parietal mechanisms disrupting the experience of body ownership and agency
(Sierra et al., 2002). Likewise, phenomenological similarities between the
inability to become emotionally aroused by visual cues (visual hypoemotion-
ality) and derealization suggest that a disruption of the process by means of
which perception becomes emotionally colored may be an underlying mech-
anism in both conditions (Sierra et al., 2002). Using event related fMRI,
compared to control subjects, patients with depersonalization disorder showed
a decrease in subcortical limbic activity as well as an increase in dorsal pre-
frontal cortical activity to emotionally arousing stimuli (Lemche et al., 2007).
Although both higher order association areas and presumptive unisensory
areas of the cerebral cortex may be multisensory in nature, evidence suggests
that the multisensory processes in the association cortex may primarily com-
pute a veridical representation of the outside world (Ghazanfar and Schroeder,
6K. Jáuregui Renaud / Multisensory Research (2015)
2006). In a Positron Emission Tomography study on depersonalization dis-
order (Simeon, 2000), comparing patients to sex-matched controls, patients
showed lower activity in the right temporal region (Brodman areas 22 & 21),
bilateral higher activity in the parietal region (Brodman areas 7B & 39) and
higher activity in the left occipital region (Brodman area 19). The results indi-
cate that depersonalization may be related to disruptions in functioning along
hierarchical sensory association areas responsible for the processing of incom-
ing perceptions against pre-existing brain templates (Simeon, 2004).
In patients with Kleine–Levin syndrome, which is characterized by episodes
of hypersomnia, cognitive impairment, apathy, derealization and behavioral
disturbances, during symptomatic periods, depersonalization/derealization
symptoms strongly correlate with hypoperfusion of the right and left parieto-
temporal junctions, which are involved in cross-modal association between
somatosensory, auditory and visual information (Kas et al., 2014).
5. Sensory Dysfunction and Depersonalization/Derealization Symptoms
Early studies conceived of depersonalization disorder as a disturbance of the
primary senses (Sierra and Berrios, 1997). Sensory dysfunction may provoke
a discrepancy between the multi-sensory frame given by experience and the
actual perception. In patients with depersonalization, across modalities, visual
unreality may be the most frequent, followed by auditory, tactile, gustatory,
and olfactory unreality (Sierra and Berrios, 2001). Using self-report measures
of imagery ability in relation to a range of symptoms, the assessment of pa-
tients with depersonalization disorder compared to age/sex matched control
subjects, showed a correlation between an impaired ability to generate visual
images, particularly images pertaining to the self and other people as opposed
to objects, with symptoms of depersonalization, other dissociative symptoms
and depressed mood (Lambert et al., 2001b).
Inversely, patients with an acquired sensory dysfunction may experience
symptoms of depersonalization/derealization (Jáuregui-Renaud, 2008a; Lip-
sanen et al., 1999). The evaluation of non-clinical volunteers has shown that
subjects with visual distortions can have higher scores for derealization, iden-
tity alteration, and depersonalization (Lipsanen et al., 1999). It is plausible
that people with visual impairment are more likely to experience problems
with functioning, which in turn leads to depression. However, controlling for
potential confounding factors, particularly activities of daily living, markedly
attenuated the association between visual impairment and depression (Evans
et al., 2007). Additionally, a history of corrected visual acuity for refraction
errors in healthy subjects may have no influence on reporting symptoms of
depersonalization/derealization, while in patients with hearing loss and those
with vestibular disease, corrected visual acuity may be related to the report
Multisensory Research (2015) DOI:10.1163/22134808-00002480 7
of depersonalization/derealization symptoms (Jáuregui-Renaud et al., 2008a).
This finding could be explained by considering that subjects with no other
sensory dysfunction, than the corrected visual acuity, would have a consistent
perception through all other senses, while in patients who have a sensory dys-
function, this ‘corrected’ vision could represent a second source of distortion
to perceive the environment (Jáuregui-Renaud et al., 2008a).
Compared to control subjects, patients with acquired hearing-loss, periph-
eral vestibular disease or bilateral retinal disease may have a higher fre-
quency of symptoms of depersonalization/derealization (Jáuregui-Renaud et
al., 2008a). Patients with retinal disease and those with vestibular disease may
show higher depersonalization/derealization scores than patients with hearing
loss and control subjects. The type of sensory dysfunction as well as the ev-
idence of symptoms of common mental disorders (GHQ12 by Goldberg and
Williams, 1988) may have an influence on the frequency and severity of symp-
toms of depersonalization/derealization assessed by self-report (questionnaire
by Cox and Swinson, 2002). This finding is consistent with the notion that sen-
sory dysfunction could provoke both, distress and a discrepancy between the
multi-sensory frame given by experience and the actual perception (Jáuregui-
Renaud et al., 2008a; Sno and Draaisma, 1993).
6. Vestibular Dysfunction and Depersonalization/Derealization
Symptoms
Increasing evidence supports that vestibular information underlies not only re-
flex responses but higher level processes, including cognition, emotion and
the sense of self through information regarding self-motion and self-location
(for reviews, see Carmona et al., 2009 and Smith and Darlington, 2013). The
coexistence of vestibular and psychiatric symptoms is supported by clinical
evidence and the relationship between vestibular pathways and the regions im-
plicated in cognitive and emotion processing in the central nervous system (for
review see Gurvich et al., 2013). In a sample of 547 patients recruited from
a specialized interdisciplinary treatment center with organic and non-organic
vertigo/dizziness, half of those with an organic cause, particularly patients
with vestibular paroxysmia or vestibular migraine, had a current psychiatric
comorbidity, with more depressive, anxiety and somatization symptoms, and
lower psychological quality of life compared with patients without psychiatric
comorbidity (Lahmann et al., 2014).
In the general population, a survey of 1287 persons using standardized self-
rating questionnaires on dizziness, depersonalization and mental distress iden-
tified depersonalization as a significant, independent predictor for dizziness
and impairment by dizziness (Tschan et al., 2013). Patients attending neuro-
otology clinics may report psychological symptoms (Eagger et al., 1992;
8K. Jáuregui Renaud / Multisensory Research (2015)
McKenna et al., 1991), including unspecific feelings of unreality (Grigsby
and Johnston, 1989), as well as symptoms of depersonalization/derealization
(Jáuregui-Renaud et al., 2008a; Kolev et al., 2014; Sang et al., 2006).
At the turn of the 20th century, the relationship between vestibular symp-
toms and depersonalization was described by Schilder (1964) and, several
decades ago, the tendency for vestibular stimulation to provoke feelings of
unreality was described in normal, healthy subjects undergoing caloric stimu-
lation (Cappon and Banks, 1961, 1965). In a more recent study (Sang et al.,
2006), healthy subjects reported that caloric stimulation provoked symptoms
of depersonalization/derealization that they had not previously experienced,
and many of these symptoms were similar to the ones reported by vestibular
patients. Reassuringly, in patients with bilateral vestibular loss, caloric stimu-
lation induced almost no symptoms.
Vestibular dysfunction may underlie unreal experiences, such as ‘Dizzi-
ness’ and ‘Feeling as if walking on shifting ground’; these symptoms are, by
definition, unreal experiences since the body is not spinning and the ground
is not moving. In patients with peripheral, vestibular disease, symptoms of
depersonalization/derealization can be related to both spatial disorientation
and symptoms of common mental disorders (Gómez-Alvarez and Jáuregui-
Renaud, 2011; Jáuregui-Renaud et al., 2008a, b; Sang et al., 2006). The more
erroneous the spatial reorientation estimates are, the more the patient ex-
periences depersonalization/derealization symptoms (Jáuregui-Renaud et al.,
2008b). Even more, patients with peripheral vestibular dysfunction and re-
cent balance symptoms may report symptoms of detachment from reality more
frequently and more severely than patients without recent balance symptoms
(Jáuregui-Renaud et al., 2008a, b), and those with incomplete recovery may re-
main disoriented (Gómez-Alvarez and Jáuregui-Renaud, 2011). This finding is
consistent with recent evidence showing that, after an acute unilateral vestibu-
lar lesion, vestibulo-ocular and vestibulo-perceptual thresholds essentially re-
flect the sensitivity of the fused peripheral receptors; while for supra-threshold
stimuli, time constants and duration of the vestibulo-ocular and vestibulo-
perceptual responses are reduced, asymmetrically for the vestibulo-ocular and
symmetrically for perception; at recovery, vestibulo-ocular responses remain
shortened and asymmetric, while vestibulo-perceptual responses normalize
(Cousins et al., 2013).
A vestibular deficit may have an impact on the multisensory mechanisms
involved with perceiving orientation in space. In order to interact with the en-
vironment, a frame of reference should be recovered. To assess the correlation
between the results of simple tests of updating spatial orientation (Jáuregui-
Renaud et al., 2008b) and the occurrence of common psychological symptoms
(questionnaires by Goldberg and Williams, 1988; Hamilton, 1960; and Zung,
1971) with depersonalization/derealization symptoms (questionnaires by Carl-
Multisensory Research (2015) DOI:10.1163/22134808-00002480 9
son et al., 1993a, and by Cox and Swinson, 2002), a three months follow-up
study was performed in patients with acute vestibular neuritis. During the first
days, patients were disoriented and reported depersonalization/derealization
symptoms and depression symptoms, including attention/concentration diffi-
culties. During the following weeks, updating spatial orientation improved,
most of the symptoms of instability disappeared (questionnaire by Jáuregui-
Renaud et al., 2003), disability declined (handicap inventory by Jacobson
and Newman, 1990) and the frequency and severity of the depersonaliza-
tion/derealization symptoms decreased (questionnaire by Cox and Swinson,
2002). The larger the decrease on the depersonalization/derealization score
was, the larger the improvement on the reorientation estimate and on the symp-
toms of instability. In this study, symptoms of anxiety were infrequent and no
evidence of an interaction between depersonalization/derealization symptoms
and symptoms of anxiety were observed. However, since symptoms of anxiety,
panic or agoraphobia frequently coexist with symptoms of depersonalization
(Cassano et al., 1989; Putnam et al., 1996), the assessment of patients with
vestibular disease with/without anxiety has shown that in patients with anxiety
the frequency and severity of the symptoms of depersonalization/derealization
may increase (Kolev et al., 2014).
Interestingly, although a strong loading on derealization symptoms was
found by the depersonalization/derealization questionnaire by Cox and Swin-
son (2002) and by the dissociative experiences scale by Carlson et al. (1993a),
patients reported a low frequency of other type of dissociative experiences
explored by the questionnaire by Carlson et al. (1993a). The depersonal-
ization/derealization questionnaire by Cox and Swinson (2002) was devel-
oped for use with clinically anxious patients to self-report depersonaliza-
tion/derealization symptoms. On the other hand, the dissociative experiences
scale inquires about the frequency of a variety of dissociative experiences, in-
cluding amnesia, depersonalization, derealization, absorption, and imaginative
involvement, but the scale will reliably measure only the general dissociation
factor (Carlson and Putnam, 1993b). The low frequency of general dissocia-
tive experiences in patients with acute, peripheral, vestibular disease suggests
that their feelings of unreality may be related to more specific deficits on the
perception of surrounding and self-consciousness, more than to the alterations
in awareness and memory for events that are related to detachment on disso-
ciation.
However, among the symptoms of depersonalization/derealization observed
during the acute phase of a vestibular deficit, the occurrence of symptoms
related to attention/concentration and its decrease during follow-up (Gómez-
Alvarez and Jáuregui-Renaud, 2011), are consistent with cross-sectional stud-
ies showing evidence of an association between vestibular function and dif-
ficulty concentrating (Yardley et al., 1998), as well as with reports on the
10 K. Jáuregui Renaud / Multisensory Research (2015)
adverse effect of vestibular dysfunction on attention processes (Redfern et
al., 2004; Smith et al., 2005; Talkowski et al., 2005). These results are in
agreement with the hypothesis that the requirement of cognitive resources
involved in successful processing and integration of vestibular information
would be increased in patients with vestibular dysfunction, and the integra-
tion of vestibular information could be associated to the cognitive resources
required for adequate spatial orientation (Talkowski et al., 2005).
In conclusion, interaction with the environment requires continuous updat-
ing of the relationship of the body and the body parts with the surrounding. The
vestibular system has widespread connections with multisensory cortical net-
works, and may provide a frame of reference within which spatial information
from other sources is interpreted. A false sense of orientation arising either
from inappropriate vestibular signals or from disordered central interpreta-
tion of vestibular information may interfere with an accurate representation of
body orientation (Saj et al., 2013) and with updating orientation during motion
(Gómez-Alvarez and Jáuregui-Renaud, 2011; Jáuregui-Renaud et al., 2008b).
This, in turn, can underlie the perception of unreality, which may decrease
with recovery, but persist whenever the inappropriate signals interfere with the
representation and continuous updating of self-orientation in the environment.
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... Presumably, it might be caused by the heavy pressure and stress of the competition. This is a dysfunction of a sensory mismatch between the mind and body (Renaud, 2015). It is a disconnectedness between one's self-perceptions and the external world (Carlson et al., 2018;Gold and Quiñones, 2020). ...
... Twisties sometimes have a psychodynamic origin, PTSD, which leads to detachment from the sense of self (Renaud, 2015), a dissociation accompanied by depersonalization and derealization . Symptoms of DDD are for sure independent risk factors for the persistence or incidence of elevated symptoms of depression/anxiety (Schlax et al., 2020;Toupet et al., 2019). ...
... In the past, twisties have been few mentioned till the 2020 Olympics. Twisties disorder is detachment from the sense of self (Renaud, 2015) in dissociation accompanied by depersonalization and derealization of athletes. Past studies have suggested that hypnosis can be one of the methods to treat the depersonalization and derealization caused by trauma in the short term (Kluft, 1992;Nash et al., 1984;Giordano et al., 2012). ...
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Research background Twisties symptoms have attracted the world's attention in the sports field since the 2020 Tokyo Olympics. Aim However, studies on the symptoms and causes, inducing mechanisms, and relationships between DP/DR (Depersonalization/Derealization Disorder) and anxiety and depression for athletes have been sparse for both the general population and athletes. The literature on the twisties issue of athletes is quite scarce in the past. Research method Adopting the criteria appealing to PRISMA Items to review the subject twisties in a broader mode and combing with the IPO (Input-Process-Output) model for triangulation testing purpose, this study categorized the literature to explore input variables causing athletes’ twisties and identified process variables in psychological mechanisms bridging suppression and finally discussed the existing possible ways in helping athletes to solve problems caused by twisties. Results The authors formed 6 propositions in summarizing twisties' influential factors and mechanisms and tried to propose solutions to reduce the stress and the relevant twisties symptom of athletes. (1) Promotion of Athletes' Mental Toughness to Resist Stressors. (2) Interventions that correct for cognitive misinterpretations and appropriate relaxation and mindfulness practice in correcting a range of attention might reduce DP/DR. (3) Monitoring the athlete's HRV test results to ensure the Athlete's ability to resist pressure. (4) Avoid organizational stressors. (5) Written Emotional Disclosure method. (6) Improve various support systems for athletes: dual career paths. (7) Athletes' Stressful Awareness about the impact of gender, seniority, and environment. Conclusion Through the theoretical dialogue on the symptom of twisties, this study helps promote the development of the research of “twisties” and depersonalization-derealization symptoms (DDS); both have been under-researched.
... Patients with vestibular dysfunctions and diseases often report feelings of unreality or strangeness. Indeed, interestingly, vestibular patients often report depersonalization and derealization symptoms (Kolev et al. 2014;Jáuregui Renaud 2015;Elyoseph et al. 2023). Depersonalization is described by feelings of unreality, detachment, or the sensation of being an external observer when it comes to one's thoughts, emotions, physical sensations, or actions. ...
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In Magnetic Resonance Imaging scanner environments, the continuous Lorentz Force is a potent vestibular stimulation. It is nowadays so well known that it is now identified as Magnetic vestibular stimulation (MVS). Alongside MVS, some authors argue that through induced electric fields, electromagnetic induction could also trigger the vestibular system. Indeed, for decades, vestibular-specific electric stimulations (EVS) have been known to precisely impact all vestibular pathways. Here, we go through the literature, looking at potential time varying magnetic field induced vestibular outcomes in MRI settings and comparing them with EVS-known outcomes. To date, although theoretically induction could trigger vestibular responses the behavioral evidence remains poor. Finally, more vestibular-specific work is needed.
... Previous theoretical and empirical work has demonstrated disrupted physiological responses in patients with DP, compared with healthy individuals (Dewe et al., 2018;Farmer et al., 2021;Owens et al., 2015;Sierra et al., 2002). DP has also been linked to disrupted activity in neuronal regions underlying somatic processing and the vestibular system (Jáuregui Renaud, 2015), which is responsible for providing information about the body's position in space (Ferrè & Haggard, 2016). ...
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... Of note is the smaller connectivity hub in left BA43, which may be somatosensory cortex for sensations generated within the ear (cf. Renaud, 2015). Equally noteworthy is the lack of significant connectivity changes between the ROI in this network and ROI corresponding to any of the other significant localized changes in gamma-band power during P2. ...
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A depersonalization episode occurred unexpectedly during an electroencephalogram (EEG) recording for a study. Experience reports tracked the time course of this event and, in conjunction, with EEG data, were analyzed. The source activity across canonical frequency bands was analyzed across four periods ended by retrospective experience reports (depersonalization was reported in the 2nd period). Delta and theta decreases occurred across all time periods with no relation to reported events. Theta and alpha increases occurred in right secondary visual areas following depersonalization, which also coincided with surges in beta and gamma. The largest increases occurred in bilateral fronto-polar and medial prefrontal cortex, followed by inferior left lateral fronto-insula-temporal cortices and right secondary visual cortex. A high frequency functional network with a principal hub in left insula closely overlapped inferior left cortical gamma band-power increases. Bilateral frontal increases in gamma are consistent with studies of dissociation. We interpret gamma and later beta, alpha, and theta band increases as arising from the generation of visual priors, in the absence of precise visual signals, which constrain interoceptive and proprioceptive predictions to reestablish a stable sense of physiological-self. Beta showed local increases following the pattern of gamma but showed no changes in functional connectivity.
... Symptoms of depersonalization may affect individuals and appear in the form of a continuous series of conditions, affecting healthy individuals in certain circumstances, and these symptoms may reach psychological and neurological disorders, as studies conducted on depersonalization indicated that it is a common phenomenon in light of stress that threatens the balance of the individual, [16]. Also, the feeling of depersonalization may cause discomfort and internal states of tension such as tension, depression, cynicism, as well as emotional, and previous experimental studies have shown a positive correlation between the nature of work and depersonalization, and these studies have revealed in general that the effect may be harmful to the emotional or psychological state For individuals, leading to depersonalization, this may cause a state of discrepancy between the feelings felt and the emotion displayed and in turn this leads to an increase in the emotional stress of the individuals in the organization, [17]. ...
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The central vestibular compensation reduces vestibular symptoms and helps individuals improve balance affected by vestibular dysfunction. The video head impulse test provides an opportunity to study central vestibular compensation objectively. This study aims to methodically present existing information about the video head impulse test as a measure to evaluate central vestibular compensation in patients with unilateral vestibular dysfunction. Literature review comprised 12 research articles selected based on pre-set criteria and timeline (January 2010 to June 2020). The findings indicate that the appropriate video head impulse test measures to evaluate central vestibular compensation after the occurrence of temporary unilateral vestibular dysfunction are the improvement in vestibulo-ocular reflex gain. And, for permanent unilateral vestibular dysfunction are reduction in catch-up saccades percentage, velocity, amplitude, latency, and Perez and Rey score.
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The vestibular system may have a critical role in the integration of sensory information and the maintenance of cognitive function. A dysfunction in the vestibular system has a significant impact on quality of life. Recent research has provided evidence of a connection between vestibular information and cognitive functions, such as spatial memory, navigation and attention. Although the exact mechanisms linking the vestibular system to cognition remain elusive, researchers have identified various pathways. Vestibular dysfunction may lead to the degeneration of cortical vestibular network regions and adversely affect synaptic plasticity and neurogenesis in the hippocampus, ultimately contributing to neuronal atrophy and cell death, resulting in memory and visuospatial deficits. Furthermore, the extent of cognitive impairment varies depending on the specific type of vestibular disease. In the present study, the current literature was reviewed, potential causal relationships between vestibular dysfunction and cognitive performance were discussed and directions for future research were proposed.
Chapter
Central vestibular forms of vertigo are caused by lesions along the vestibular pathways in the brainstem, which extend from the vestibular nuclei in the medulla oblongata to the ocular motor nuclei and integration centers in the rostral midbrain, and to the vestibulocerebellum, the thalamus, and multisensory vestibular cortex areas in the temporoparietal cortex (Brandt and Dieterich 1994; Dieterich and Brandt 1993a; Baier et al. 2008; Baier and Dieterich 2009) (. Fig. 13.1). In tertiary interdisciplinary outpatient dizziness units, central vestibular disorders including vestibular migraine comprise about 25% of the established diagnoses (Newman-Toker et al. 2008; Kerber et al. 2017; Vanni et al. 2015; Brandt and Dieterich 2017; Zwergal and Dieterich 2020).
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Objectives: Peripheral vestibular disorders except from reflexes dysfunction correspond also to cognitive decline. The objectives of this cross-sectional study were to a) identify correlations among variables of functional gait, cognitive function, and perceived dizziness and b) explore variables that could be used as prognostic factors of functional gait in people with peripheral vestibular deficits. Methods: We recruited 154 people with peripheral vestibular deficits. The participants presented with moderate disability in terms of the Dizziness Handicap Inventory questionnaire (mean: 48.00, 95% confidence interval: 45.24-50.75), deficits in the Functional Gait Assessment test (mean: 22.75, 95% confidence interval: 22.13-23.40) and indication of mild cognitive impairment based on Montreal Cognitive Assessment tool (mean: 25.18, 95% confidence interval: 24.75-25.60). Results: Statistically significant correlations found among functional gait and gender, age, educational level, perceived level of disability and the total score of the Montreal Cognitive Assessment tool. Several components of the cognitive screening test (executive function, vigilance, language skills, verbal fluency) also correlated statistically significant with functional gait. Linear regression models revealed that age, perceived level of disability and vigilance significantly predicted functional gait variability (R2 = 0.350; p < 0.001) as well as high risk of falling, as indicated by a score on Functional Gait Assessment test <22/30 (R2 = 0.380). Conclusions: Cognitive impairments affect functional gait in people with peripheral vestibular disorders. Thus, the integration of cognitive functional assessment must be considered as a prerequisite for functional assessment and designing rehabilitation programs that will include dual task training.
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The central nervous system must resolve the ambiguity of inertial motion sensory cues in order to derive an accurate representation of spatial orientation. Adaptive changes during spaceflight in how the brain integrates vestibular cues with other sensory information can lead to impaired movement coordination, vertigo, spatial disorientation, and perceptual illusions after return to Earth. The purpose of this study was to compare tilt and translation motion perception in astronauts before and after returning from spaceflight. We hypothesized that these stimuli would be the most ambiguous in the low-frequency range (i.e., at about 0.3 Hz) where the linear acceleration can be interpreted either as a translation or as a tilt relative to gravity. Verbal reports were obtained in eleven astronauts tested using a motion-based tilt-translation device and a variable radius centrifuge before and after flying for two weeks on board the Space Shuttle. Consistent with previous studies, roll tilt perception was overestimated shortly after spaceflight and then recovered with 1-2 days. During dynamic linear acceleration (0.15-0.6 Hz, ±1.7 m/s2) perception of translation was also overestimated immediately after flight. Recovery to baseline was observed after 2 days for lateral translation and 8 days for fore-aft translation. These results suggest that there was a shift in the frequency dynamic of tilt-translation motion perception after adaptation to weightlessness. These results have implications for manual control during landing of a space vehicle after exposure to microgravity, as it will be the case for human asteroid and Mars missions.
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Background: Spatial disorientation is a significant factor in a large percentage of military Class A aviation mishaps. While previous studies have analyzed accident statistics, they often suffer from methodological flaws, which lead to questionable conclusions. Methods: The current study relied upon the Air Force Safety Automated System to document U.S. Air Force Class A mishap investigations during the past 21 yr. Human Factors Analysis and Classification System codes were used to determine mishaps involving pilot spatial disorientation. The data were combined with data from the Reliability and Maintainability Information System to determine the accident rate per flight hour. Results: There were 72 spatial disorientation (SD) mishaps analyzed, resulting in loss of 101 lives and 65 aircraft since fiscal year (FY) 1993 for a total monetary cost of 2.32 billion. Class A mishaps involving spatial disorientation had a higher rate as a function of hours flown for helicopter and fighter/attack fixed wing aircraft than other aircraft. Additionally, mishap rates for F-16 fighter/attack aircraft were marginally larger than for other fighter/attack aircraft. Although SD mishaps at night had similar mishap rates to daytime SD mishaps when adjusted by flight hours, SD mishaps account for a larger percent of Class A mishaps during the night than during the day. Discussion: SD mishaps were analyzed in terms of Class A mishaps per million flight hours. Results indicate that future SD research should be focused on fighter/attack and helicopter platforms. Updates to the Air Force safety center database are recommended.
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Background Vertigo and dizziness are often not fully explained by an organic illness, but instead are related to psychiatric disorders. This study aimed to evaluate psychiatric comorbidity and assess psychosocial impairment in a large sample of patients with a wide range of unselected organic and non-organic (ie, medically unexplained) vertigo/dizziness syndromes. Methods This cross-sectional study involved a sample of 547 patients recruited from a specialised interdisciplinary treatment centre for vertigo/dizziness. Diagnostic evaluation included standardised neurological examinations, structured clinical interview for major mental disorders (SCID-I) and self-report questionnaires regarding dizziness, depression, anxiety, somatisation and quality of life. Results Neurological diagnostic workup revealed organic and non-organic vertigo/dizziness in 80.8% and 19.2% of patients, respectively. In 48.8% of patients, SCID-I led to the diagnosis of a current psychiatric disorder, most frequently anxiety/phobic, somatoform and affective disorders. In the organic vertigo/dizziness group, 42.5% of patients, particularly those with vestibular paroxysmia or vestibular migraine, had a current psychiatric comorbidity. Patients with psychiatric comorbidity reported more vertigo-related handicaps, more depressive, anxiety and somatisation symptoms, and lower psychological quality of life compared with patients without psychiatric comorbidity. Conclusions Almost half of patients with vertigo/dizziness suffer from a psychiatric comorbidity. These patients show more severe psychosocial impairment compared with patients without psychiatric disorders. The worst combination, in terms of vertigo-related handicaps, is having non-organic vertigo/dizziness and psychiatric comorbidity. This phenomenon should be considered when diagnosing and treating vertigo/dizziness in the early stages of the disease.
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