The Effect of Low-Level Laser Stimulation on Hearing Thresholds

• ClinicalTrials.gov Identifier: NCT01820416
• Recruitment Status: Terminated
• First Posted: March 28, 2013
• Results First Posted: June 1, 2017
• Last Update Posted: June 1, 2017
• Sponsor: University of Iowa
• Collaborator: GN Resound
• Information provided by (Responsible Party): Shawn Goodman, University of Iowa

• Study Type: Interventional
• Study Design: Allocation: Randomized; Intervention Model: Parallel Assignment; Masking: Triple (Participant, Investigator, Outcomes Assessor); Primary Purpose: Treatment
• Condition: Hearing Loss
• Interventions: Radiation: Low-level Laser Therapy; Other: Placebo Comparator: Disabled Laser
• Enrollment: 35

Participant Flow

Recruitment Details
Pre-assignment Details

Arm/Group Title	Low-Level Laser Therapy	Disabled Laser	Control
Arm/Group Description	Low-level laser applied for approximately 4 minutes to the area around the pinna, the back of the neck, and the top of the head. Low-level Laser Therapy: Portable unit containing two laser diodes producing 532 and 635 nm wavelengths. Both diodes produced energy levels of 7.5 mw (class IIIb). Beams from both diodes were dispersed through lenses to create parallel line-generated beams, rather than spots. The 532 nm light was constant, and the 635 nm light was pulsed, with frequencies of 15 and 33 Hz. The pulsing alternated between frequencies every 30 seconds.	Low-level laser device with laser diodes disabled. Also applied for approximately 4 minutes to the area around the pinna, the back of the neck, and the top of the head. Placebo Comparator: Disabled Laser: Portable unit containing two DISABLED laser diodes. Same protocol was followed as for the Experimental (radiation) group, except that the disabled diodes produced no radiation.	Visit laboratory using same schedule as experiment and placebo. No Low-level laser or any treatment applied. Used to assess normal test-retest variability.
Period Title: Overall Study
Started	12	12	11
Completed	9	10	11
Not Completed	3	2	0

Baseline Characteristics

Arm/Group Title		Low-Level Laser Therapy	Disabled Laser	Control	Total
Arm/Group Description		Low-level laser applied for approximately 4 minutes to the area around the pinna, the back of the neck, and the top of the head. Low-level Laser Therapy: Portable unit containing two laser diodes producing 532 and 635 nm wavelengths. Both diodes produced energy levels of 7.5 mw (class IIIb). Beams from both diodes were dispersed through lenses to create parallel line-generated beams, rather than spots. The 532 nm light was constant, and the 635 nm light was pulsed, with frequencies of 15 and 33 Hz. The pulsing alternated between frequencies every 30 seconds.	Low-level laser device with laser diodes disabled. Also applied for approximately 4 minutes to the area around the pinna, the back of the neck, and the top of the head.	Visit laboratory using same schedule as experiment and placebo. No Low-level laser or any treatment applied. Used to assess normal test-retest variability.	Total of all reporting groups
Overall Number of Baseline Participants		12	12	11	35
Baseline Analysis Population Description		[Not Specified]
Age, Continuous; Mean (Standard Deviation); Unit of measure: Years
	Number Analyzed	12 participants	12 participants	11 participants	35 participants
		51.33 (15.37)	55.58 (11.42)	47.09 (16.71)	51.46 (14.57)
Sex: Female, Male; Measure Type: Count of Participants; Unit of measure: Participants
	Number Analyzed	12 participants	12 participants	11 participants	35 participants
	Female	6 50.0%	5 41.7%	5 45.5%	16 45.7%
	Male	6 50.0%	7 58.3%	6 54.5%	19 54.3%
Race and Ethnicity Not Collected [1]; Measure Type: Count of Participants; Unit of measure: Participants
	Number Analyzed	0 participants	0 participants	0 participants	0 participants
					0
		[1] Measure Analysis Population Description: Race and Ethnicity were not collected from any participant.
Region of Enrollment; Measure Type: Number; Unit of measure: Participants
United States	Number Analyzed	12 participants	12 participants	11 participants	35 participants
		12	12	11	35

Outcome Measures

1. Primary Outcome

Title	Change in Speech Perception
Description	Hearing status, as assessed by the Connected Sentence Test (CST). Difference scores (post-test - pretest) are reported. The CST approximates everyday conversation. Scoring is based on the number of correctly repeated key words. Higher numbers indicate better scores. The minimum score is 0 (0%) and the maximum is 100 (100%). When comparing test-retest scores for an individual, Cox et al. (1988) suggest that changes of 15% or more (based on 100 key words) are indicative of significant changes. We subtracted the post-test from the pre-test, so that negative difference scores indicate worse performance, and positive difference scores indicate better performance. Difference scores with an absolute value smaller than 15 are interpreted as no significant change. In addition, pre- and post-test performance was assessed for groups using t-tests on the difference scores.
Time Frame	7-10 days after baseline measures recorded

Outcome Measure Data

Analysis Population Description

[Not Specified]

Arm/Group Title	Low-Level Laser Therapy	Disabled Laser	Control
Arm/Group Description:	Low-level laser applied for approximately 4 minutes to the area around the pinna, the back of the neck, and the top of the head. Low-level Laser Therapy: Portable unit containing two laser diodes producing 532 and 635 nm wavelengths. Both diodes produced energy levels of 7.5 mw (class IIIb). Beams from both diodes were dispersed through lenses to create parallel line-generated beams, rather than spots. The 532 nm light was constant, and the 635 nm light was pulsed, with frequencies of 15 and 33 Hz. The pulsing alternated between frequencies every 30 seconds.	Low-level laser device with laser diodes disabled. Also applied for approximately 4 minutes to the area around the pinna, the back of the neck, and the top of the head. Placebo Comparator: Disabled Laser: Portable unit containing two DISABLED laser diodes. Same protocol was followed as for the Experimental (radiation) group, except that the disabled diodes produced no radiation.	Visit laboratory using same schedule as experiment and placebo. No Low-level laser or any treatment applied. Used to assess normal test-retest variability.
Overall Number of Participants Analyzed	9	10	11
Mean (Standard Deviation); Unit of Measure: difference scores
	-1.571 (6.949)	2.286 (8.46)	-2.8 (5.329)

Adverse Events

Time Frame	Adverse event data were collected during the time that the study was being conducted (from 09/01/2009 to 12/31/2009).
Adverse Event Reporting Description	[Not Specified]
Arm/Group Title	Low-Level Laser Therapy	Disabled Laser	Control
Arm/Group Description	Low-level laser applied for approximately 4 minutes to the area around the pinna, the back of the neck, and the top of the head. Low-level Laser Therapy: Portable unit containing two laser diodes producing 532 and 635 nm wavelengths. Both diodes produced energy levels of 7.5 mw (class IIIb). Beams from both diodes were dispersed through lenses to create parallel line-generated beams, rather than spots. The 532 nm light was constant, and the 635 nm light was pulsed, with frequencies of 15 and 33 Hz. The pulsing alternated between frequencies every 30 seconds.	Low-level laser device with laser diodes disabled. Also applied for approximately 4 minutes to the area around the pinna, the back of the neck, and the top of the head.	Visit laboratory using same schedule as experiment and placebo. No Low-level laser or any treatment applied. Used to assess normal test-retest variability.
All-Cause Mortality
	Low-Level Laser Therapy	Disabled Laser	Control
	Affected / at Risk (%)	Affected / at Risk (%)	Affected / at Risk (%)
Total	--/--	--/--	--/--
Serious Adverse Events
	Low-Level Laser Therapy	Disabled Laser	Control
	Affected / at Risk (%)	Affected / at Risk (%)	Affected / at Risk (%)
Total	0/12 (0.00%)	0/12 (0.00%)	0/11 (0.00%)
Other (Not Including Serious) Adverse Events
Frequency Threshold for Reporting Other Adverse Events	0%
	Low-Level Laser Therapy	Disabled Laser	Control
	Affected / at Risk (%)	Affected / at Risk (%)	Affected / at Risk (%)
Total	0/12 (0.00%)	0/12 (0.00%)	0/11 (0.00%)

Limitations and Caveats

[Not Specified]

More Information

Certain Agreements

Principal Investigators are NOT employed by the organization sponsoring the study.

There is NOT an agreement between Principal Investigators and the Sponsor (or its agents) that restricts the PI's rights to discuss or publish trial results after the trial is completed.

Results Point of Contact

• Name/Title: Shawn S Goodman
• Organization: Dept. of Communication Sciences & Disorders, University of Iowa
• Phone: 319-335-8700
• EMail: shawn-goodman@uiowa.edu

Publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):

Goodman SS, Bentler RA, Dittberner A, Mertes IB. The effect of low-level laser therapy on hearing. ISRN Otolaryngol. 2013 Apr 23;2013:916370. doi: 10.1155/2013/916370. eCollection 2013.

• Responsible Party: Shawn Goodman, University of Iowa
• ClinicalTrials.gov Identifier: NCT01820416
• Other Study ID Numbers: 200808718
• First Submitted: March 25, 2013
• First Posted: March 28, 2013
• Results First Submitted: March 1, 2017
• Results First Posted: June 1, 2017
• Last Update Posted: June 1, 2017