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Parasympathetic Nervous System Dysfunction, as Identified by Pupil Light Reflex, and Its Possible Connection to Hearing Impairment.

Wang Y, Zekveld AA, Naylor G, Ohlenforst B, Jansma EP, Lorens A, Lunner T, Kramer SE - PLoS ONE (2016)

Bottom Line: We summarized the information in these data according to different types of parasympathetic-related diseases.Both studies reported a reduced parasympathetic activity in the hearing impaired groups.Maximum constriction velocity and relative constriction amplitude appear to be the most sensitive parameters.

View Article: PubMed Central - PubMed

Affiliation: Section Ear & Hearing, Dept. of Otolaryngology-Head and Neck Surgery and EMGO Institute for Health and Care Research, VU University medical center, Amsterdam, The Netherlands.

ABSTRACT

Context: Although the pupil light reflex has been widely used as a clinical diagnostic tool for autonomic nervous system dysfunction, there is no systematic review available to summarize the evidence that the pupil light reflex is a sensitive method to detect parasympathetic dysfunction. Meanwhile, the relationship between parasympathetic functioning and hearing impairment is relatively unknown.

Objectives: To 1) review the evidence for the pupil light reflex being a sensitive method to evaluate parasympathetic dysfunction, 2) review the evidence relating hearing impairment and parasympathetic activity and 3) seek evidence of possible connections between hearing impairment and the pupil light reflex.

Methods: Literature searches were performed in five electronic databases. All selected articles were categorized into three sections: pupil light reflex and parasympathetic dysfunction, hearing impairment and parasympathetic activity, pupil light reflex and hearing impairment.

Results: Thirty-eight articles were included in this review. Among them, 36 articles addressed the pupil light reflex and parasympathetic dysfunction. We summarized the information in these data according to different types of parasympathetic-related diseases. Most of the studies showed a difference on at least one pupil light reflex parameter between patients and healthy controls. Two articles discussed the relationship between hearing impairment and parasympathetic activity. Both studies reported a reduced parasympathetic activity in the hearing impaired groups. The searches identified no results for pupil light reflex and hearing impairment.

Discussion and conclusions: As the first systematic review of the evidence, our findings suggest that the pupil light reflex is a sensitive tool to assess the presence of parasympathetic dysfunction. Maximum constriction velocity and relative constriction amplitude appear to be the most sensitive parameters. There are only two studies investigating the relationship between parasympathetic activity and hearing impairment, hence further research is needed. The pupil light reflex could be a candidate measurement tool to achieve this goal.

No MeSH data available.


Related in: MedlinePlus

demonstration of one pupil light reflex on pupillometry.The light onsets at the ‘0’ point; Phase 1 is a fast constriction mainly controlled by PNS; Phase 2 is a fast redilation under the control of both PNS and SNS; Phase 3 is a slow redilation phase, predominantly controlled by SNS activity.
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pone.0153566.g002: demonstration of one pupil light reflex on pupillometry.The light onsets at the ‘0’ point; Phase 1 is a fast constriction mainly controlled by PNS; Phase 2 is a fast redilation under the control of both PNS and SNS; Phase 3 is a slow redilation phase, predominantly controlled by SNS activity.

Mentions: Fig 2 is a schematic illustration of a pupil light reflex. The light stimulus onsets at time zero, and the constriction starts with a latency of about 200 ms. A standard light reflex contains three phases, 1) a fast constriction, followed by 2) a fast redilation of the pupil, and then 3) a slow redilation where the pupil recovers to its original size. The pupil constricts rapidly in the beginning, then after it reaches its maximum constriction velocity (point MCV in Fig 2), the constriction becomes slower until the minimum diameter is reached. The latency of constriction, maximum constriction velocity, and absolute constriction amplitude (difference between baseline and minimum pupil diameter) are the usual parameters used in pupil light reflex analysis and will be more closely defined later in the result section. In general, reduced PNS activity is characterized by longer constriction latency, slower maximum constriction velocity and smaller constriction amplitude of the pupil light reflex [2]. According to Loewenfeld and Lowenstein [2], PNS plays a dominant role during the pupil constriction phase, while SNS contribution is negligible. On the other hand, both PNS and SNS innervate the pupil in the beginning of the redilation phase. Thus, in theory, observing the constriction part of the pupil light reflex provides an indicator of PNS activity uncontaminated by SNS activity.


Parasympathetic Nervous System Dysfunction, as Identified by Pupil Light Reflex, and Its Possible Connection to Hearing Impairment.

Wang Y, Zekveld AA, Naylor G, Ohlenforst B, Jansma EP, Lorens A, Lunner T, Kramer SE - PLoS ONE (2016)

demonstration of one pupil light reflex on pupillometry.The light onsets at the ‘0’ point; Phase 1 is a fast constriction mainly controlled by PNS; Phase 2 is a fast redilation under the control of both PNS and SNS; Phase 3 is a slow redilation phase, predominantly controlled by SNS activity.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4835104&req=5

pone.0153566.g002: demonstration of one pupil light reflex on pupillometry.The light onsets at the ‘0’ point; Phase 1 is a fast constriction mainly controlled by PNS; Phase 2 is a fast redilation under the control of both PNS and SNS; Phase 3 is a slow redilation phase, predominantly controlled by SNS activity.
Mentions: Fig 2 is a schematic illustration of a pupil light reflex. The light stimulus onsets at time zero, and the constriction starts with a latency of about 200 ms. A standard light reflex contains three phases, 1) a fast constriction, followed by 2) a fast redilation of the pupil, and then 3) a slow redilation where the pupil recovers to its original size. The pupil constricts rapidly in the beginning, then after it reaches its maximum constriction velocity (point MCV in Fig 2), the constriction becomes slower until the minimum diameter is reached. The latency of constriction, maximum constriction velocity, and absolute constriction amplitude (difference between baseline and minimum pupil diameter) are the usual parameters used in pupil light reflex analysis and will be more closely defined later in the result section. In general, reduced PNS activity is characterized by longer constriction latency, slower maximum constriction velocity and smaller constriction amplitude of the pupil light reflex [2]. According to Loewenfeld and Lowenstein [2], PNS plays a dominant role during the pupil constriction phase, while SNS contribution is negligible. On the other hand, both PNS and SNS innervate the pupil in the beginning of the redilation phase. Thus, in theory, observing the constriction part of the pupil light reflex provides an indicator of PNS activity uncontaminated by SNS activity.

Bottom Line: We summarized the information in these data according to different types of parasympathetic-related diseases.Both studies reported a reduced parasympathetic activity in the hearing impaired groups.Maximum constriction velocity and relative constriction amplitude appear to be the most sensitive parameters.

View Article: PubMed Central - PubMed

Affiliation: Section Ear & Hearing, Dept. of Otolaryngology-Head and Neck Surgery and EMGO Institute for Health and Care Research, VU University medical center, Amsterdam, The Netherlands.

ABSTRACT

Context: Although the pupil light reflex has been widely used as a clinical diagnostic tool for autonomic nervous system dysfunction, there is no systematic review available to summarize the evidence that the pupil light reflex is a sensitive method to detect parasympathetic dysfunction. Meanwhile, the relationship between parasympathetic functioning and hearing impairment is relatively unknown.

Objectives: To 1) review the evidence for the pupil light reflex being a sensitive method to evaluate parasympathetic dysfunction, 2) review the evidence relating hearing impairment and parasympathetic activity and 3) seek evidence of possible connections between hearing impairment and the pupil light reflex.

Methods: Literature searches were performed in five electronic databases. All selected articles were categorized into three sections: pupil light reflex and parasympathetic dysfunction, hearing impairment and parasympathetic activity, pupil light reflex and hearing impairment.

Results: Thirty-eight articles were included in this review. Among them, 36 articles addressed the pupil light reflex and parasympathetic dysfunction. We summarized the information in these data according to different types of parasympathetic-related diseases. Most of the studies showed a difference on at least one pupil light reflex parameter between patients and healthy controls. Two articles discussed the relationship between hearing impairment and parasympathetic activity. Both studies reported a reduced parasympathetic activity in the hearing impaired groups. The searches identified no results for pupil light reflex and hearing impairment.

Discussion and conclusions: As the first systematic review of the evidence, our findings suggest that the pupil light reflex is a sensitive tool to assess the presence of parasympathetic dysfunction. Maximum constriction velocity and relative constriction amplitude appear to be the most sensitive parameters. There are only two studies investigating the relationship between parasympathetic activity and hearing impairment, hence further research is needed. The pupil light reflex could be a candidate measurement tool to achieve this goal.

No MeSH data available.


Related in: MedlinePlus