Non-pharmacological Auditory and Somatosensory Stimulation in Anesthetic Emergence

Effects of Non-pharmacological Auditory and Somatosensory Stimulation on the Efficiency and Quality of Emergence From General Anesthesia

This study intends to employ verbal stimulation, tactile stimulation, and kinetic stimulation as interventions during the emergence phase from general anesthesia to facilitate recovery.

Study Overview

• Status: Recruiting
• Conditions: General Anesthetic; Electroencephalographic
• Intervention / Treatment: Behavioral: Verbal Stimulation; Behavioral: Shoulder Tapping; Behavioral: Shoulder Shaking

Detailed Description

General anesthesia is an indispensable component of modern surgical practice. While its induction mechanisms have been relatively well elucidated, the mechanisms underlying emergence-namely the restoration of consciousness following anesthesia-remain incompletely understood. Emergence from anesthesia represents a critical stage of anesthetic management, with its efficiency and quality directly influencing postoperative recovery, patient safety, and the incidence of complications. Traditionally, anesthesia induction and emergence were considered to be symmetrical and passive processes, with emergence regarded as the reverse of induction that naturally occurs as anesthetic drug concentrations decline. However, recent advances in neuroscience suggest that anesthetic emergence is not merely a passive reversal but rather an actively regulated, multidimensional neurophysiological process with modulatory potential, and it is not entirely symmetrical to induction. Studies have demonstrated that neuronal activity in the cortex, activation patterns of brain regions, and neurotransmitter regulation during emergence differ substantially from those observed during induction. Key regulatory pathways implicated in this process include orexinergic neurons and the locus coeruleus-noradrenergic system. These findings provide a theoretical foundation for strategies aimed at facilitating emergence from general anesthesia.

Evidence further indicates that the sequence of functional recovery across different brain regions is heterogeneous during emergence. Clinical observations suggest that auditory perception is among the earliest sensory modalities to recover during anesthetic emergence. This phenomenon is of notable clinical significance, as it underlies the longstanding use of auditory interventions-such as calling a patient's name or giving verbal commands-in the operating room. Compared with other sensory modalities such as vision or nociception, auditory pathways regain responsiveness earlier. Although the precise neural mechanisms remain unclear, they are likely related to the auditory system, language processing circuits, and higher-order cortical integration of language. Recent advances in neuroimaging techniques, including electroencephalography (EEG) and functional magnetic resonance imaging (fMRI), provide further support for this perspective. For example, a previous study demonstrated via intracranial recordings that during propofol anesthesia, the core auditory cortex continued to generate early auditory evoked potentials and frequency-following responses to 50 Hz sound stimuli, indicating preserved early cortical responses. Similarly, another study showed that following loss of consciousness, the primary auditory cortex retained rapid responses to auditory input, whereas higher-order cortical responses were markedly attenuated. These findings suggest that auditory cortices can respond to external auditory stimuli even in the early stages of emergence when anesthetic concentrations remain pharmacologically significant, thereby supporting the use of auditory stimulation in facilitating recovery. Moreover, recent studies have investigated how specific linguistic content (e.g., a patient's own name) and acoustic characteristics (e.g., familiar voices) influence emergence quality. One study found that calling a patient's name elicited stronger responses and facilitated awakening more effectively than generic verbal cues. Similarly, another research reported that playback of maternal voice recordings shortened extubation time and reduced the incidence of emergence delirium in pediatric patients.

In addition to auditory stimulation, non-verbal somatosensory interventions are also commonly applied in clinical practice to promote emergence. Nevertheless, research on the role of such non-verbal stimulation in emergence from general anesthesia remains limited. Previous research demonstrated that acupuncture at acupoints such as Renzhong and Yongquan could accelerate the recovery of consciousness after general anesthesia. However, standardized protocols and robust evidence supporting the use of mechanical somatosensory stimulation to facilitate emergence are currently lacking. And its specific stimulation methods, intensity, timing of intervention, and safety parameters remain unclear.

Animal studies demonstrated in that electrical stimulation of glutamatergic neurons in the brainstem parabrachial nucleus can induce recovery of the righting reflex and behavioral arousal in mice under sustained isoflurane anesthesia, accompanied by a marked reduction in electroencephalographic δ waves. Subsequent studies further confirmed that stimulating glutamatergic neurons in the parabrachial nucleus accelerated anesthetic emergence, underscoring the critical role of this brainstem pathway in arousal regulation. The parabrachial nucleus is an important node in the central arousal network; its activation drives norepinephrine and dopamine release from the hypothalamus and brainstem, thereby enhancing cortical arousal. These findings suggest that peripheral somatosensory stimulation may ascend via spinal pathways to brainstem structures, thereby activating ascending arousal centers and accelerating recovery of consciousness. This provides a neurobiological basis for the use of peripheral somatosensory or spinal stimulation as non-invasive awakening strategies; however, clinical trials systematically validating such interventions remain lacking.

Although numerous studies have explored pharmacologic and non-pharmacologic approaches to accelerate emergence from general anesthesia, there is a paucity of randomized controlled trials evaluating the effectiveness and safety of non-verbal somatosensory stimulation. This approach is simple to implement, has a favorable safety profile, and does not increase healthcare costs. Its effects on emergence efficiency, emergence quality, and postoperative complications (e.g., delayed emergence, agitation) warrant systematic investigation, and such findings would provide evidence for clinical guidelines on anesthetic emergence.

Furthermore, electroencephalography (EEG), as a non-invasive method for real-time monitoring of brain function, is widely applied in assessing anesthetic depth and recovery of consciousness. Studies have shown that during emergence from general anesthesia, EEG exhibits characteristic changes, such as a reduction in high-amplitude slow waves, reappearance of α oscillations, and a gradual increase in β activity. Incorporating EEG frequency dynamics into the study design may help elucidate the neural mechanisms by which stimulation interventions modulate the arousal process, offering more direct neurophysiological evidence to optimize both monitoring and intervention strategies during anesthetic emergence.

In summary, the investigators propose to conduct a prospective, randomized controlled clinical trial to systematically investigate, in patients undergoing laparoscopic abdominal surgery under combined intravenous and inhalational general anesthesia, the effects of non-verbal somatosensory stimulation, either alone or in combination with verbal stimulation, compared with the conventional approach of verbal name-calling. Outcomes of interest include postoperative emergence time, quality, and safety. This study aims to provide robust scientific evidence to inform optimized intervention strategies for anesthetic emergence.

• Study Type: Interventional
• Enrollment (Estimated): 205
• Phase: Not Applicable

Contacts and Locations

• Study Contact: Name: Prof. Du; Phone Number: +86 18980602213; Email: duguizhi@scu.edu.cn

Study Locations

• China
  • Sichuan
    • Chengdu, Sichuan, China, 610041
      • Recruiting
      • West China Hospital of Sichuan University
      • Contact: Prof. Du; Phone Number: +86 18980602213; Email: duguizhi@scu.edu.cn

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Adult patients aged 18 to 65 years, with American Society of Anesthesiologists (ASA) physical status I-III;
2. Scheduled for laparoscopic abdominal surgery, including gastric, colorectal, or biliary procedures;

Exclusion Criteria:

1. ASA physical status IV;
2. Body mass index (BMI) greater than 30 kg/m²;
3. Presence of underlying neurological dysfunction, cognitive impairment, or auditory disorders;
4. Neurological, cardiovascular, hepatic, or renal dysfunction;
5. Current use of antipsychotic medications or a history of psychiatric illness;
6. History of alcohol abuse or substance dependence;
7. Exposure to general anesthesia or sedation within 1 month prior to surgery;
8. Presence of intracranial implants or a history of epilepsy;
9. Known allergy to any drugs used in this study;
10. Preoperative use of electronic hearing aids or implanted auditory devices;
11. Refusal to participate in the study.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

5

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Verbal Stimulation Group:	Behavioral: Verbal Stimulation; Patients will wear headphones connected to a voice playback device that delivers pre-recorded verbal stimuli. Each voice message will last approximately 3 seconds, with a speech rate of 200-300 ms per character, and the volume will be set at a normal speaking level (60 dB). After each playback, there will be a 10-second interval before the next repetition, and the verbal stimulus will be played three times per intervention cycle.If the patient shows no eye opening or clear response, the standard verbal stimulation procedure will be repeated after a 3-minute interval, until a response is observed.
Experimental: Shoulder Tapping Group	Behavioral: Shoulder Tapping; No audio will be played through the patient's headphones. Upon discontinuation of anesthetic agents, the investigator will begin tapping the patient's left shoulder. All operators will receive standardized training to ensure procedural consistency. The tapping frequency will be 2 taps per second, i.e., six taps within 3 seconds, paced using a metronome to maintain rhythm uniformity. Each tapping event (six taps over 3 seconds) will last 3 seconds, followed by a 10-second interval before the next tapping event.
Experimental: Shoulder Shaking Group	Behavioral: Shoulder Shaking; No audio will be played through the patient's headphones. Upon discontinuation of anesthetic agents, the investigator will begin gently shaking the patient's left shoulder.All investigators will undergo standardized training to ensure consistency of operation. Each shaking event (three shakes within 3 seconds) will last 3 seconds, followed by a 10-second interval before the next shaking event. Each intervention cycle will include three shaking events.
Experimental: Combined Verbal + Shoulder Tapping Group	Behavioral: Verbal Stimulation; Patients will wear headphones connected to a voice playback device that delivers pre-recorded verbal stimuli. Each voice message will last approximately 3 seconds, with a speech rate of 200-300 ms per character, and the volume will be set at a normal speaking level (60 dB). After each playback, there will be a 10-second interval before the next repetition, and the verbal stimulus will be played three times per intervention cycle.If the patient shows no eye opening or clear response, the standard verbal stimulation procedure will be repeated after a 3-minute interval, until a response is observed.; Behavioral: Shoulder Tapping; No audio will be played through the patient's headphones. Upon discontinuation of anesthetic agents, the investigator will begin tapping the patient's left shoulder. All operators will receive standardized training to ensure procedural consistency. The tapping frequency will be 2 taps per second, i.e., six taps within 3 seconds, paced using a metronome to maintain rhythm uniformity. Each tapping event (six taps over 3 seconds) will last 3 seconds, followed by a 10-second interval before the next tapping event.
Experimental: Combined Verbal + Shoulder Shaking Group	Behavioral: Verbal Stimulation; Patients will wear headphones connected to a voice playback device that delivers pre-recorded verbal stimuli. Each voice message will last approximately 3 seconds, with a speech rate of 200-300 ms per character, and the volume will be set at a normal speaking level (60 dB). After each playback, there will be a 10-second interval before the next repetition, and the verbal stimulus will be played three times per intervention cycle.If the patient shows no eye opening or clear response, the standard verbal stimulation procedure will be repeated after a 3-minute interval, until a response is observed.; Behavioral: Shoulder Shaking; No audio will be played through the patient's headphones. Upon discontinuation of anesthetic agents, the investigator will begin gently shaking the patient's left shoulder.All investigators will undergo standardized training to ensure consistency of operation. Each shaking event (three shakes within 3 seconds) will last 3 seconds, followed by a 10-second interval before the next shaking event. Each intervention cycle will include three shaking events.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Time to first eye opening	defined as the interval from discontinuation of anesthetic agents to the moment the patient opens both eyes in response to a verbal command and is able to keep them open for at least 5 seconds.	Perioperative

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Changes in EEG power	Alterations in power across specific EEG frequency bands (e.g., Delta, Theta, Alpha, Beta) at the time of first eye opening	Perioperative
Time to target BIS values	Time required for the BIS to reach 70, 80, and 90 after discontinuation of desflurane	Perioperative
Extubation time	Interval from discontinuation of desflurane to removal of the endotracheal tube	Perioperative
Emergence agitation	Highest score on the Riker Sedation-Agitation Scale (SAS) observed during emergence. The SAS ranges from 1 to 7, with higher scores indicating greater agitation and a worse outcome. Assessed from extubation to time before arrival in the post-anesthesia care unit.	Perioperative
Sedation depth after extubation	Sedation level assessed using the Richmond Agitation-Sedation Scale (RASS) during emergence from anesthesia. The RASS ranges from -5 (unarousable) to +4 (combative), with higher scores indicating more agitation and lower scores indicating deeper sedation. Assessed from extubation to 30 minutes after arrival in the post-anesthesia care unit.	Perioperative
Hemodynamic parameters	Mean arterial pressure (MAP) and heart rate (HR) recorded	Perioperative
Length of stay in PACU	Length of stay in PACU	Perioperative
Postoperative analgesic use	Total amount of analgesic administered in the PACU	Perioperative
Use of antiemetics	Antiemetic medications administered in the PACU	Perioperative
Incidence of agitation in the PACU	Proportion of patients with a Riker Sedation-Agitation Scale score ≥ 5. Assessed in the first 30 minutes after arrival in the post-anesthesia care unit.	Perioperative
Pain scores in the PACU	Pain intensity assessed using the Numeric Rating Scale (NRS), where 0 indicates no pain and 10 indicates the worst possible pain. Higher scores indicate more severe pain. Assessed at 10 minutes, 20 minutes, and 30 minutes after arrival in the post-anesthesia care unit.	Perioperative

Collaborators and Investigators

• Sponsor: West China Hospital

Publications and helpful links

General Publications

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• Purdon PL, Pierce ET, Mukamel EA, Prerau MJ, Walsh JL, Wong KF, Salazar-Gomez AF, Harrell PG, Sampson AL, Cimenser A, Ching S, Kopell NJ, Tavares-Stoeckel C, Habeeb K, Merhar R, Brown EN. Electroencephalogram signatures of loss and recovery of consciousness from propofol. Proc Natl Acad Sci U S A. 2013 Mar 19;110(12):E1142-51. doi: 10.1073/pnas.1221180110. Epub 2013 Mar 4.
• Purdon PL, Sampson A, Pavone KJ, Brown EN. Clinical Electroencephalography for Anesthesiologists: Part I: Background and Basic Signatures. Anesthesiology. 2015 Oct;123(4):937-60. doi: 10.1097/ALN.0000000000000841.
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• Sessler CN, Gosnell MS, Grap MJ, Brophy GM, O'Neal PV, Keane KA, Tesoro EP, Elswick RK. The Richmond Agitation-Sedation Scale: validity and reliability in adult intensive care unit patients. Am J Respir Crit Care Med. 2002 Nov 15;166(10):1338-44. doi: 10.1164/rccm.2107138.
• Mashour GA, Palanca BJ, Basner M, Li D, Wang W, Blain-Moraes S, Lin N, Maier K, Muench M, Tarnal V, Vanini G, Ochroch EA, Hogg R, Schwartz M, Maybrier H, Hardie R, Janke E, Golmirzaie G, Picton P, McKinstry-Wu AR, Avidan MS, Kelz MB. Recovery of consciousness and cognition after general anesthesia in humans. Elife. 2021 May 10;10:e59525. doi: 10.7554/eLife.59525.
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Study record dates

Study Major Dates

• Study Start (Actual): October 11, 2025
• Primary Completion (Estimated): June 30, 2027
• Study Completion (Estimated): June 30, 2027

Study Registration Dates

• First Submitted: December 15, 2025
• First Submitted That Met QC Criteria: January 4, 2026
• First Posted (Actual): January 14, 2026

Study Record Updates

• Last Update Posted (Actual): January 14, 2026
• Last Update Submitted That Met QC Criteria: January 4, 2026
• Last Verified: January 1, 2026

More Information

Terms related to this study

• Keywords: EEG; Emergence; General anesthesia; Somatosensory stimulation; Verbal stimulation; Recovery of consciousness
• Other Study ID Numbers: WestChinaHospital 2025（1900）

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES
• IPD Plan Description: Deidentified individual participant data will be available upon reasonable request from the corresponding author after publication and ethical approval. Data will be shared via email request to the corresponding author within 6 months after publication.

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No