In the preceding section we mentioned that the experiences that are part of both the secondary and tertiary features of sleep paralysis are described as "hallucinations" in the conventional scientific literature on sleep paralysis. In this section we will argue that at least some of the tertiary features may involve processes at a higher level than pure neurocognitive processes, more precisely that a full-blown RISP episode may induce some specific paranormal phenomena. The most obvious phenomenon is the "Out-of-Body Experience" (OBE) that seems to occur from the beginning of the second phase of a full-blown episode . To describe this phenomenon we have used the words "proprioceptive" and "autoscopic hallucinations" in the preceding section. On the other hand, There is also considerable evidence that people who tend to have OBEs also tend to have lucid dreams, flying and falling dreams, and the ability to control their dreams [35-37]. Because of the strong connection between OBEs and lucid dreaming, some researchers in the area have suggested that OBEs are a type of lucid dream [38-40]. One problem with this argument is that although people who have OBEs are also likely to have lucid dreams, OBEs are far less frequent, and can happen to people who have never had lucid dreams. Furthermore, OBEs are quite plainly different from lucid dreams in that during a typical OBE the experiencer is convinced that the OBE is a real event happening in the physical world and not a dream, unlike a lucid dream, in which by definition the dreamer is certain that the event is a dream. There is an exception that connects the two experiences: when we feel ourselves leaving the body, but also know that we are dreaming. However this last case seems not to apply to RISP because the RISP experiencer is generally convinced of the reality of his experience. S. LaBerge  stresses that even if some or most OBEs were in fact dreams or lucid dreams, we cannot say that a genuine OBE is impossible. However, he suggests that if you have an OBE, why not test to see if the OBE-world passes the reality test. Several different modalities (visual, auditory, etc...) can be used simultaneously as cues to distinguish a dream or a hallucination from a real experience: For example, is the room you are in the one you are actually sleeping in? If you have left your physical body, where is it? Do things change when you are not looking at them (or when you are)? Can you read something twice and have it remain the same on both readings? LaBerge asks: "If any of your questions and investigations leave you doubting that you are in the physical world, is it not logical to believe you are dreaming?"
In the case of RISP at least, the decision of whether one (or rather one's phantom body or "non-physical double") sees the physical world during a RISP episode or instead one sees a dream world is often very difficult to make. From many accounts that can be found on the UCLA sleep web site where the respondents reported having an OBE during an ISP/RISP episode and from the personal experiences of the authors, at least during some episodes the physical world seems to be perceived, such as the room of the experiencer his physical body (most often seen from above), various objects in the room, or the ceiling of the room, etc... A reality check made upon waking up positively identifies what has been perceived during the episode with the actual surroundings, but there are occasionally some anomalies, such as objects that were seen in the room during the episode but are in fact not there, or distortions of actual objects. One could argue that somehow, the mind has played a trick on the experiencer by "mimicking" or "cloning" the actual surroundings, that is, recording them as a memory inside the brain while in the wake state and "projecting" them in a dream world during a RISP episode. This is not a plausible explanation if one considers that it is not possible to "pre-record" in the wake state an actual image of oneself as seen from above (or from different viewpoints), as it is perceived during some episodes. Instead, we are led to conjecture that it is not impossible that a genuine OBE could occur simultaneously with oniric imagery, with both external and internally generated stimuli being processed concurrently. The OBE component could be called "the signal" since it refers to sensing external stimuli that are part of the physical world, and the oniric imagery could constitute a form of "noise" if we are mainly interested in the paranormal phenomenon of the OBE instead of other possible paranormal phenomena associated with dreams. Hence there could be a superposition of two states; a conscious state carried out by the OBE and a dream state characterized by oniric imagery.
A statement made by C. Tart is in a sense strikingly similar to our conjecture: on the basis of his laboratory experiments, he concluded that perhaps the OBEs are a mixture of dreams and "something else" . This something else might, he thought, be an Extra-Sensory Perception (ESP), such as a genuine OBE. We should point out, however, that C. Tart did not mention the words "sleep paralysis" in his research and we do not know if the subjects in his experiments had sleep paralysis episodes or were having OBEs without the paralysis. Finally, it is also entirely possible that some RISP episodes might include only lucid dreaming, some others genuine OBEs and still others a superposition of a genuine OBE and of a dream-state. Conversely, OBEs could occur in a variety of states, not only during RISP episodes. Indeed, We point out some similarities that exist between some RISP episodes and Near-Death-Experiences (NDE). As R. Moody writes :
"A man is dying and, as he reaches the point of greatest physical distress, he hears himself pronounced dead by his doctor. He begins to hear an uncomfortable noise, a loud ringing or buzzing, and at the same time feels himself moving very rapidly through a long dark tunnel. After this, he suddenly finds himself outside of his own physical body, but still in the immediate physical environment, and he sees his own body from a distance, as though he is a spectator. He watches the resuscitation attempt from this unusual vantage point and is in a state of emotional upheaval."
One can immediately recognize some common components: the buzzing/ringing sound in the ears, the OBE, and the tunnel that is seen during some RISP episodes. Moreover, occasionally intense RISP episodes include other common elements with NDEs, such as a feeling of peace and ineffability, vivid and beautiful landscapes, a light that appears at the end of the tunnel and that is bright but does not hurt the eyes, etc... The question then is: Are NDEs some form of sleep paralysis episode, or do some intense RISP episodes mimic what is experienced near death? Unfortunately, to our knowledge, no research has addressed those two questions until now.
Another parallel may be made between the perceived OBE during the second phase of a full-blown RISP episode and, in seemingly completely different circumstances, the "ability" of shamans to "leave their body" at will and explore other "realms of existence." As is stated by J. Halifax in [42a]:
"The shaman, lord of the three realms of sky, earth and the underworld, is an individual endowed with the ability to enter profound trance states, a "technician of ecstasy," as Mircea Eliade has so aptly termed this religious specialist [42b]. In these visionary states, the shaman is open to contact with animal allies and spirit helpers. Or the wizard may leave his or her body behind like a husk while the disincarnate soul journeys to the celestial realms above or the underworld of disease and death."
It is interesting to note that shamanic initiation involves acute physical illness that may lead to near-death states (hence a possible connection with NDEs) and/or an intense psychological crisis [42a]. Shamans have learned to control their "OBEs," whereas the vast majority of RISP experiencers, already subjected to an intense fear at the onset of a RISP episode, seem, to say the least, to be extremely puzzled if they access the tertiary features with the main feature being the "OBE" itself. In any case, the perceived OBE seems to be the main phenomenon linking full-blown RISP episodes to NDEs or to shamanic experiences.
Finally, some intriguing aspects of RISP that are also part of the tertiary features are the tingling or vibrating sensations that are experienced during some episodes, as well as bright flashes of light or sensations of explosion in the head. Such sensations match quite closely those that are described in the literature of Kundalini manifestations . Kundalini experiences also include the feeling of leaving one's body, but they include also other phenomena that do not occur in RISP episodes. One important fact is that people who have what they consider Kundalini manifestations usually practice some form of Yoga that can produce changes in states of the mind. That is, they may be engaged in meditative practices, which can reach a point similar to the condition of falling asleep. When that happens, it is plausible that the phenomena the meditators experience might be similar to, if not the same as those experienced in RISP. For example, let us consider the following account by Gopi Krishna :
"During one such spell of intense concentration [on a shining lotus] I suddenly felt a strange sensation below the base of the spine, at the place touching the seat ... The sensation extended upwards, growing in intensity... Suddenly, with a roar like that of a waterfall, I felt a stream of liquid light entering my brain through the spinal cord ... The illumination grew brighter and brighter, the roaring louder. I experienced a rocking sensation and then felt myself slipping out of my body, entirely enveloped in a halo of light."
One should note here that Kundalini manifestations, as described in Gopi Krishna's autobiography, as well in other references , , may have a lot more impact and consequences than the phenomena experienced by individuals ISP/RISP episodes, in the sense that they have the potential for profound life transformations. Meditation practices may increase the occurrence of RISP in an individual, with the associated OBEs, flashes of light and vibrating sensations, but the meditator generally controls much more the Kundalini manifestations arising from the meditation than individuals who do not meditate control the phenomena experienced during their RISP episodes. In conclusion, if we consider that genuine OBEs are indeed possible during RISP episodes, one important issue to address is: how are then external visual/auditory stimuli (visual/auditory information from the actual world) captured by the "non-physical body double" and how are they transmitted to the brain of the experiencer for interpretation and for future recall? Once again, until now it seems that no research has addressed this important issue.