Bone Conduction Head Sensitivity Mapping: 

Bone Vibrator 

by Maranda McBride, Tomasz R. Letowski, and Phuong K. Tran 

ARL-TR-3556 July 2005 

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Army Research Laboratory 

Aberdeen Proving Ground, MD 21005-5425 

ARL-TR-3556 July 2005 

Bone Conduction Head Sensitivity Mapping: 

Bone Vibrator 

Maranda McBride 

North Carolina A&T State University 

Tomasz R. Letowski and Phuong K. Tran 

Human Research and Engineering Directorate, ARL 

Approved for public release; distribution is unlimited. 
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 Bone Conduction Head Sensitivity Mapping: Bone Vibrator 

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6. AUTHOR(S) 

 Maranda McBride (NC A&T State Univ); Tomasz R. Letowski and 

 Phuong K. Tran (both of ARL) 

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 U.S. Army Research Laboratory 

 Human Research and Engineering Directorate 

 Aberdeen Proving Ground, MD 21005-5425

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 Approved for public release; distribution is unlimited.

13. SUPPLEMENTARY NOTES 

14. ABSTRACT 

The military is interested in ways to incorporate radio communication in a multi-tasking environment. Bone conduction 

(BC) radio communication is an attractive means to communicate because it offers the ability to transmit and receive radio 

communication without compromising auditory awareness of the environment. Several companies are attempting to 

accommodate the needs of the military by creating communication devices that incorporate BC technologies. However, the 

effectiveness of these devices differs in many respects. One factor that affects the detectability of signals received via BC is 

the location of the BC transmitter (vibrator) on the head of the user. The intent of this study was to identify optimal 

locations for the placement of a BC vibrator, based on hearing threshold levels of various signals. Eleven signals were 

transmitted via bone conduction to 11 head locations of 12 volunteers. Results of the study indicate that the condyle (an 

articular prominence of a bone) is the most receptive location for a BC transducer because it generates the lowest overall 

threshold levels. Other sensitive and thus recommended locations include vertex, mastoid, and temple. The jaw angle 

location also resulted in relatively low threshold levels; however, it is difficult to maintain a stable position of the vibrator at 

this location, and therefore, this position is not recommended. 

15. SUBJECT TERMS

 auditory research; bone conduction; hearing threshold 

16. SECURITY CLASSIFICATION OF:

19a. NAME OF RESPONSIBLE PERSON

 Tomasz R. Letowski 

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Unclassified 

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Unclassified 

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Prescribed by ANSI Std. Z39.18
iii 

Contents 

List of Figures iv

List of Tables iv

1. Introduction 1

2. Method 2

2.1 Participants ......................................................................................................................2 

2.2 Instrumentation................................................................................................................3 

2.3 Procedure.........................................................................................................................4 

2.4 Vibrator Locations...........................................................................................................4 

3. Results 6

3.1 Experimental Results.......................................................................................................6 

3.2 Symmetry Test ................................................................................................................7 

4. Discussion 8

5. Conclusions 9

6. References 10

Appendix A. Arithmetic Means of BC Responses Per Signal 11

Appendix B. Arithmetic Means of BC Responses Per Location 17

Appendix C. Head Views 23

Appendix D. Location Ranks 35 

Distribution List 36 
iv 

List of Figures 

Figure 1. Block diagram of the instrumentation used in the study. .............................................. 3 

Figure 2. Experimental task flow chart.......................................................................................... 5 

Figure 3. Vibrator locations. .......................................................................................................... 6 

List of Tables 

Table 1. BC hearing threshold means and standard deviations ..................................................... 7 

Table 2. Location rank tallies......................................................................................................... 7 
1 

1. Introduction 

Effective completion of military mission requires Soldiers to maintain auditory awareness of their 

environment, protect themselves from the hazardous effects of noise, and maintain two-way radio 

communication. Air conduction (AC) and bone conduction (BC) are two alternate audio interfaces 

for two-way radio communication. In the case of AC, the sounds are transmitted from a talker to a 

microphone and from a loudspeaker or an earphone to the listener’s ear. With BC, sounds are 

transmitted through vibrations from the skull of the talker to a contact microphone and from a 

vibrator to the skull of the listener. In both cases, sound quality and intelligibility of transmitted 

speech depend on the technical parameters of the electro-acoustic transducers, their coupling with 

the users (talker and listener), and technical parameters of the transmission channel. 

AC is the basic means of hearing and is much better understood than BC in terms of communication applications. Although BC is always induced by sound waves arriving at the head of the 

listener, its effectiveness is about 40 dB less than that of AC. Further, during BC, transmission 

sound waves at lower frequencies are impeded less than sound waves at higher frequencies; 

therefore, complex sound waves transmitted by BC may appear to be carrying less high frequency 

energy in comparison to air-conducted sounds (Newby, 1979). In order to compensate for these 

deficiencies, BC transmission requires the use of special contact microphones and vibrators 

directly coupled with and well matched to the skull of the user. 

In military operations, BC communication may be a preferred means of radio communication over 

the traditional AC communication because it enables the Soldiers to hear verbal radio communications without eliminating their awareness of the acoustic environment. Such awareness is 

greatly compromised by the use of earphones or in-the-ear devices not equipped with a hearing 

restoration system. BC communication is also attractive because the transducers are lightweight, 

inconspicuous, and easily integrated into military headgear. These devices have proved their 

ability to provide necessary radio communication in quiet and high noise environments, especially 

when combined with an appropriate hearing protection system (Letowski et al., 2004, 2005). 

However, because of the issues described previously, it is imperative to determine the best 

coupling conditions for BC transducers used in military headgear in order to ensure that their use 

does not inhibit the safety and survivability of military personnel. 

The effectiveness of BC communication greatly depends on where the transducers are placed on 

the head since skin thickness and bone structure varies between locations as well as between 

individuals (Studebaker, 1962). Although there have been some American National Standards 

Institute (ANSI) standards for BC hearing testing, they do not apply to the use of BC devices in 

military headgear. First, the physical design of BC devices used in military headgear does not 

conform to the design of the devices upon which the BC hearing standards are based. Standards 

such as ANSI S3.13-1987 and ANSI S3.43-1992 are based on vibrators with a specific circular 
2 

tip that protrudes slightly beyond the surface of the vibrator. Many of the vibrators incorporated 

into prototype communication headgear have a completely flat surface area and some are 

rectangular. Further, standardized testing methodology applies only to the BC transducers 

placed at the mastoid bone or forehead. Last but definitely not least, there are no standardized 

methods to measure static force applied to the vibrator. 

The primary purpose of this research was to measure and compare the detectability of signals 

received via BC vibrators at different points on the listener’s skull. Since the human head is a 

complex mechanical system with many modes of vibration and non-uniform mechanical 

properties, the location on the head to which signals are transmitted may affect how well 

listeners are able to detect and recognize the signals. The vibrator used in the study was 

comparable to the style of vibrator currently sought for military headgear. Since the detection 

of signals in a single ear was not of interest, masking and occlusion were not used in this study. 

Data obtained from this study will fill an important gap in our knowledge regarding head 

vibration patterns and will have immediate application for Future Force Warrior radio 

communication systems. The reported study is the first stage of the broader research program 

intended to determine the optimum number and locations of BC devices, both vibrators and 

contact microphones, for use in radio communication interfaces. 

The main objective of the present study was to create a physical mapping of the head that 

identifies the pure tone detectability level of signals received via BC devices placed in various 

locations on the human head. The secondary objective was to compare these data with 

detectability data for several complex signals. The practical implications of this effort were to 

identify favorable and unfavorable contact points on the head for the placement of mechanical 

devices used to receive radio transmissions via bone conduction. The head mapping data will 

also be used in future studies to extend the understanding of the perception of simple and 

complex sounds via BC devices. 

2. Method 

2.1 Participants 

Twelve participants between the ages of 18 and 42 participated in the study. All participants had 

normal hearing for pure-tone octave frequencies from 250 Hz through 8000 Hz (ANSI S3.6-1996) 

and hearing symmetry within 10 dB for all signals. The audiometric tests were conducted with an 

Interacoustics clinical audiometer AC40, Telephonics TDH-39 earphones, and a response button. 

Each listener was tested in a sound-treated booth that complied with ANSI S3.1-1999 requirements 

for hearing testing, and the audio equipment was calibrated before the testing. Participants were 
3 

not required to have experience in psychophysical studies. Demographic information was also 

collected from the participants. 

2.2 Instrumentation 

Following the hearing test, each participant was seated at the listening station. The listening 

station consisted of an Oticon1

 A20 BC vibrator, static force sensor, electronic voltmeter, 

headband, and a response push button (figure 1). The static force sensor was employed to 

measure and monitor the static force applied to the skull by the vibrator in order to maintain the 

repeatability of the mechanical excitation provided by the vibrator at various locations on the 

head. If the static force were allowed to vary considerably from one location to another, 

thresholds measured at various locations might not be comparable because of the differences in 

coupling the vibrator to the skull. 

Figure 1. Block diagram of the instrumentation used 

in the study. 

According to audiology-related literature, the static force applied by a bone vibrator to the human 

head must fall within the range of 2.5 newtons (N) (minimum force required for a stable position) 

and 5.9 N (the level of discomfort) in order to make a strong, yet comfortable coupling between 

the vibrator and the head. ANSI S3.43-1992, the standard used in the calibration of pure-tone BC 

audiometers, suggests a static force between 4.9 N and 5.9 N inclusively. However, this level of 

force is very uncomfortable for certain vibrator locations. Therefore, the target static force used 

in this study was between 3.9 N and 4.9 N inclusively for all vibrator locations and participants. 

This force range is identical to the force range recommended for coupling TDH2

-39 earphones to 

the head during audiometric testing (ANSI S3.6-1991). 

Pure-tone signals were generated with the same audiometer used to conduct the audiometric test 

(Interacoustics clinical audiometer AC40). Speech and white noise signals were generated on a 

personal computer via Sound Forge3

 6.0 software. The computer was connected to the audiometer, 

 1

Oticon is a registered trademark of Oticon A/S. 

2

TDH stands for telephonics dynamic headphone.

3Sound Forge is a registered trademark of Sony.

Static 

Force 

Vibrator

Static Force 

Sensor 

Electronic

Voltmeter
4 

which was used to adjust the signal level (in decibels [dB]) for all signals. Two pure-tone signals, 

125 Hz and 250 Hz, were generated by computer because the audiometer was unable to generate a 

BC signal at the appropriate intensity levels for these frequencies. The orders of signal 

presentation and vibrator location were randomized between listeners. 

2.3 Procedure 

Each participant was asked to listen to incoming signals from the vibrator placed on his or her 

head and to respond by pressing the push button when the signal was heard. The incoming 

sounds were 125-, 250-, 500-, 1000-, 2000-, 4000-, and 8000-Hz pure tones, a burst of white 

noise, and three pre-recorded speech sounds (“aah,” “eee,” and “ooh”). An adjustable headband 

was used to hold the vibrator against the head, and the static force sensor was placed between the 

headband and the vibrator surface. 

A reversed Hughson-Westlake procedure (Newby, 1979) was used to present test signals and to 

determine listeners’ hearing thresholds for each signal-location combination. At the beginning 

of a test trial, the signal was set to a specific frequency and presented at a clearly audible (but not 

loud) sound level (e.g., 40 dB hearing level). The participant’s task was to press the push button 

when s/he heard the signal. If the participant responded to the signal, the sound level was 

reduced by 10 dB. If the participant did not respond to the signal, the sound level was increased 

by 5 dB (ANSI S3.21-1997; Suter, 1993). This process was repeated several times until a signal 

level resulting in a 50% response rate was obtained for a given test signal. This marked the end 

of a trial. The procedure was repeated until hearing thresholds for all 11 signals and 11 locations 

were measured and recorded. Participants were able to take “stretch” breaks after every other 

vibrator location. See figure 2 for a flow chart of the experimental procedure. 

2.4 Vibrator Locations 

The vibrator locations used in this study were determined before experimentation and were the 

same for all participants. Figure 3 shows all the vibrator locations used in the study and the code 

names used for their identification. Some of the locations were chosen because they are common 

locations for BC vibrators and have been used before (i.e., the mastoid [G], forehead [C], and 

vertex [K]) (Frank, 1982; Richter and Brinkmann, 1981; Studebaker, 1962) or because they are 

being considered for use as bone conduction vibrator locations (A, B, F, and I). Others were 

chosen because they are commonly known electroencephalograph (EEG) electrode locations, 

making them easy to identify (D, E, H, and J). 
5 

Figure 2. Experimental task flow chart. 
6 

Figure 3. Vibrator locations. 

3. Results 

3.1 Experimental Results 

All data collected in this study were subjected to basic statistical processing (means, variances, 

etc.) and exploratory data analyses (histograms, scatter plots, etc.). The two independent 

variables investigated in this study were (a) the type of sound (11 signals) and (b) the location of 

the vibrator (11 locations). The dependent variable was the hearing threshold level. Participants 

were treated as a random effects variable, and vibrator location, sound frequency, sound type, 

and sound level were treated as fixed effects variables. Effects were considered significant if the 

probability of difference because of chance was less than 0.05 (p < 0.05). 

Participant means, standard deviations, minimum, and maximum values were calculated for each 

location-signal combination. Table 1 shows the means and standard deviations for each location 

per signal. The standard deviations ranged from 4.01 to 17.35 dB with an average value of 

9.65 dB. Graphical representations of mean data are included in appendix A (location versus 
7 

signal) and appendix B (signal versus location). Appendix C provides graphical depictions of 

the average threshold at each of the locations on the human head for individual signals. 

For each signal, the locations were sorted on the basis of their mean threshold value. The “best” 

contact point for a signal was defined as the location with the lowest threshold value. The 

locations were ranked so that the location with the lowest threshold value was at the top of the 

list (#1) and the one with the highest value was at the bottom of the list (#11). The rankings for 

each of the locations per signal are included in appendix D. The summary of the rankings per 

location is shown in table 2. 

Table 1. BC hearing threshold means and standard deviations. 

Table 2. Location rank tallies. 

3.2 Symmetry Test 

In the process of designing this study, the feasibility of testing symmetric locations on the head 

(e.g., right/left condyle, right/left jaw angle, right/left temple, etc.) was considered. However, 

such an approach would increase the number of test points and would greatly extend the duration 

of the study per listener. Therefore, to limit the number of test points, it was determined that there 

would be no need to test symmetric locations if the assumption could be made that there is no 

significant difference in the thresholds between points of symmetry. This assumption seems to be 

justified if the listeners have fairly symmetrical AC hearing. Thus, all the listeners participating 

in this study were screened for symmetrical AC hearing (see section 2.1). To verify the 

correctness of this assumption, one set of symmetric points (right and left mastoid) was also 

tested and analyzed. 
8 

Because the data spread of BC thresholds obtained in this study was not normally distributed (as 

indicated by the Anderson-Darling test statistic p < 0.05), a Mann-Whitney test was performed 

on the raw data to determine if there was a significant difference between the frequency 

thresholds at the two mastoid locations. The results of this test indicated that the threshold 

difference between these two locations was not statistically significant (p = 0.1901). Therefore, 

for the purpose of the study, it was assumed that mirror data points would have threshold values 

sufficiently close to those obtained at original measurement points. 

4. Discussion 

The thresholds obtained from this study were much lower than those obtained from clinical 

studies. This may be because the signals were presented by a reverse Hughson-Westlake 

procedure. Hirsh (1952) found that lower thresholds are usually obtained when the intensity of 

the signal goes from high to low rather than from low to high. 

Based on the inspection of the graphs provided in appendix B, the threshold levels for the signals 

per location generally decreased as frequency increased; however, evidence of “notching” (or an 

elevated increase) was found at 4000 Hz for most locations. O’Neill, Frosh, and Jayaraj (2000) 

observed a similar phenomenon at 2000 Hz for a set of clinical data. 

Based on the average thresholds for the 11 signals, the condyle appears to be the “best” contact 

point for BC vibrators. Of the 11 signals, the condyle was ranked number 1 for eight signals and 

either number 2 or 3 for the other three signals. The average ranking for the condyle placement 

was 1.4. The next best contact point was the mastoid with an average rank of 3.3. 

The results of this study indicate that the condyle would be a good location to place BC 

vibrators. This location falls outside the helmet coverage area but is sufficiently close to be 

incorporated in headgear-supported BC interface designs. In addition, the condyle has the 

advantage of being close enough to the ear canal that any residual signal emanating from the 

vibrator because of acoustic leakage can be heard via AC. This may be an important practical 

consideration for low-power systems operating in quiet (stealth) environments. 

Other locations with high rankings include the jaw angle, which primarily ranked first, second, 

or third, and the vertex, which was usually ranked second, third, or fourth. This indicates that all 

these locations are good candidates for vibrator location for radio communication purposes. The 

consistently poor performers included the chin, which never ranked better than ninth; Pz, which 

was ranked no higher than seventh; and FPz, which also was ranked no higher than seventh. 

Table 2 shows a tally of the number of times a location ranked first, second, third, etc. 

The temple location used in this study was actually the location on the bone just above the 

temple; however, this proved to be a very difficult point for properly placing and securing a 
9 

vibrator. Moreover, it is a dangerous place for military applications since placing anything very 

close to the temple creates a health hazard. However, obtained data and informal comments 

made by the listeners indicate that the “temple location” may be a relatively effective location, 

especially if the transducer is placed a little bit higher than indicated on the head diagram. Thus, 

if the “temple location” is to be used in future studies, it needs to be considered as the place on 

the skull about 1 inch above the actual temple. Based on informal observations made by the 

listeners participating in this study, this may be a safer yet even more sensitive location than the 

specific temple location used in the study. 

5. Conclusions 

Based on the quantitative data and rankings, the “best” effective location for the BC vibrator 

used in radio communication headgear appears to be the condyle, followed by the mastoid and 

vertex. Although the jawbone ranked third, it was very difficult to hold the vibrator in place at 

this location. This complication would be intensified in situations when the person wearing the 

vibrator was expected to speak, thus having to move the jaw. Since the temple ranked fifth 

overall and had resulted in good informal feedback from the listeners, the “above-the-temple” 

location should also be considered in further studies. 

In summary, the results of the study provide a basic sensitivity map of the human skull for 

directly transmitted vibrations. The condyle, mastoid, and vertex have been identified in this 

order as the most promising locations for vibration detection. A location on the side of the head 

about 1 inch above the temple may also be good. Future studies are needed to provide more 

definitive answers regarding the feasibility of using these locations with specific protective 

headgear and BC vibrators of various designs. 
10 

6. References 

American National Standards Institute. American National Standard: Mechanical Coupler for 

Measurement of Bone Vibrators. New York: American National Standards Institute, Inc. 1987, 

ANSI S3.13-1987 (Revision of ANSI S3.13-1972). 

American National Standards Institute. American National Standard: Standard Reference Zero for 

the Calibration of Pure-Tone Bone-Conduction Audiometers. New York: American National 

Standards Institute, Inc. 1992, ANSI S3.43-1992. 

American National Standards Institute. American National Standard: Specification for Audiometers. 

New York: American National Standards Institute, Inc. 1996, ANSI S3.6-1996. 

American National Standards Institute. National Standard Method for Manual Pure-Tone Threshold 

Audiometry. New York: American National Standards Institute, Inc. 1997, ANSI S3.21-1997 

(Revision of ANSI S3.21-1978). 

American National Standards Institute. American National Standard: Maximum Permissible 

Ambient Noise Levels for Audiometric Test Rooms. New York: American National Standards 

Institute, Inc. 1999, ANSI S3.1-1999 (Revision of ANSI S3.1-1991). 

Frank, T. Forehead versus mastoid threshold differences with a circular tipped vibrator. Ear and 

Hearing 1982, 3 (2), 91–92. 

Hirsh, I. J. Chapter 4. In The Measurement of Hearing; New York: McGraw-Hill Book Company, 

Inc, 1952. 

Letowski, T.R.; Mermagen, T.; Vause, N.; Henry, P. Bone Conduction Communication in Noise: A 

Preliminary Study. Proceedings of the XXI International Congress on Sound and Vibrations, St. 

Petersburg, Russia, 2004; ICSV, pp 3037-3044. 

Letowski, T.R.; Henry, P.; Mermagen, T. Use of Bone Conduction Transmission for Communication 

With Mounted and Unmounted Soldiers. Proceedings of the ASNE Human System Integration 

Symposium on “Enhancing Combat Effectiveness Through War Fighter Performance,”

Arlington, VA, June 2005. 

Newby, H. Audiology, 4th edition; Englewood Cliffs, New Jersey: Prentice-Hall, Inc, 1979. 

O’Neill, G.; Frosh, A. C.; Jayaraj, S. M. Systematic errors in bone conduction audiometry. Clinical 

Otolaryngol 2000, 25, 468–470. 

Richter, U.; Brinkmann, K. Threshold of hearing by bone conduction. Scandinavian Audiology

1981, 10, 235–238. 

Studebaker, G. A. Placement of Vibrator in Bone-Conduction Testing. Journal of Speech and 

Hearing Research 1962, 5 (4), 321–331. 

Suter, A. H. Hearing Conservation Manual, 3rd Edition; Milwaukee, WI: Council for Accreditation 

in Occupational Hearing Conservation, 1993. 
11 

Appendix A. Arithmetic Means of BC Responses Per Signal 
12 
13 
14 
15 
16 
17 

Appendix B. Arithmetic Means of BC Responses Per Location 
18 
19 
20 
21 
22 
23 

Appendix C. Head Views 
24 
25 
26 
27 
28 
29 
30 
31 
32 
33 
34 
35 

Appendix D. Location Ranks 
36 

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NO. OF 

COPIES ORGANIZATION

 1 ARMY RSCH LABORATORY - HRED 

 AVNC FIELD ELEMENT 

 ATTN AMSRD ARL HR MJ D DURBIN 

 BLDG 4506 (DCD) RM 107 

 FT RUCKER AL 36362-5000 

 1 ARMY RSCH LABORATORY - HRED 

 ATTN AMSRD ARL HR MK MR J REINHART 

 10125 KINGMAN RD 

 FT BELVOIR VA 22060-5828 

 1 ARMY RSCH LABORATORY - HRED 

 ATTN AMSRD ARL HR MV HQ USAOTC 

 S MIDDLEBROOKS 

 91012 STATION AVE ROOM 111 

 FT HOOD TX 76544-5073 

 1 ARMY RSCH LABORATORY - HRED 

 ATTN AMSRD ARL HR MY M BARNES 

 2520 HEALY AVE STE 1172 BLDG 51005 

 FT HUACHUCA AZ 85613-7069 

 1 ARMY RSCH LABORATORY - HRED 

 ATTN AMSRD ARL HR MP D UNGVARSKY 

 BATTLE CMD BATTLE LAB 

 415 SHERMAN AVE UNIT 3 

 FT LEAVENWORTH KS 66027-2326 

 1 ARMY RSCH LABORATORY - HRED 

 ATTN AMSRD ARL HR M DR B KNAPP 

 ARMY G1 MANPRINT DAPE MR 

 300 ARMY PENTAGON ROOM 2C489 

 WASHINGTON DC 20310-0300 

 1 ARMY RSCH LABORATORY - HRED 

 ATTN AMSRD ARL HR MJK MS D BARNETTE 

 JFCOM JOINT EXPERIMENTATION J9 

 JOINT FUTURES LAB 

 115 LAKEVIEW PARKWAY SUITE B 

 SUFFOLK VA 23435 

 1 ARMY RSCH LABORATORY - HRED 

 ATTN AMSRD ARL HR MQ M R FLETCHER 

 US ARMY SBCCOM NATICK SOLDIER CTR 

 AMSRD NSC SS E BLDG 3 RM 341 

 NATICK MA 01760-5020 

 1 ARMY RSCH LABORATORY - HRED 

 ATTN AMSRD ARL HR MT DR J CHEN 

 12350 RESEARCH PARKWAY 

 ORLANDO FL 32826-3276 
38 

NO. OF 

COPIES ORGANIZATION

 1 ARMY RSCH LABORATORY - HRED 

 ATTN AMSRD ARL HR MS MR C MANASCO 

 SIGNAL TOWERS RM 303A 

 FORT GORDON GA 30905-5233 

 1 ARMY RSCH LABORATORY - HRED 

 ATTN AMSRD ARL HR MU M SINGAPORE 

 6501 E 11 MILE RD MAIL STOP 284 

 BLDG 200A 2ND FL RM 2104 

 WARREN MI 48397-5000 

 1 ARMY RSCH LABORATORY - HRED 

 ATTN AMSRD ARL HR MF MR C HERNANDEZ 

 BLDG 3040 RM 220 

 FORT SILL OK 73503-5600 

 1 ARMY RSCH LABORATORY - HRED 

 ATTN AMSRD ARL HR MW E REDDEN 

 BLDG 4 ROOM 332 

 FT BENNING GA 31905-5400 

 1 ARMY RSCH LABORATORY - HRED 

 ATTN AMSRD ARL HR MN R SPENCER 

 DCSFDI HF 

 HQ USASOC BLDG E2929 

 FORT BRAGG NC 28310-5000 

 1 ARL-HRED LIAISON 

 PHYSICAL SCIENCES LAB 

 PO BOX 30002 

 LAS CRUCES NM 88003-8002 

 1 DIRECTOR 

 UNIT OF ACTION MANEUVER BATTLE LAB 

 ATTN ATZK UA 

 BLDG 1101 

 FORT KNOX KY 40121 

 2 SENSORY DEVICES INC

 ATTN H HOLSOPPLE W PIROTH

 205 MAIN ST

 NEW EAGLE PA 15067 

 1 DOUGLAS BRUNGART 

 SENIOR COMPUTER ENGINEER 

 HUMAN EFFECTIVENESS DIREC 

 2610 SEVENTH ST 

 WRIGHT PATTERSON AFB OH 45433-7901 

 1 OFC OF NAVAL RESEARCH 

 MEDICAL/BIOLOGICAL SCI & TECH DIV 

 ATTN R D SHILLING 

 ARLINGTON VA 22217-5860 

NO. OF 

COPIES ORGANIZATION

 1 NATL GROUND INTELLIGENCE CTR 

 ATTN INSCOM JOHN MONROE 

 BLDG 4465 

 2055 BOULDERS RD 

 CHARLOTTESVILLE VA 22911-8318 

 ABERDEEN PROVING GROUND

 1 DIRECTOR 

 US ARMY RSCH LABORATORY 

 ATTN AMSRD ARL CI OK (TECH LIB) 

 BLDG 4600 

 3 US ARMY CTR FOR HEALTH PROMOTION 

 AND PREVENTIVE MEDICINE 

 ATTN JOSEPH KNAPIK THOMAS HELFER 

 DOUGLAS OHLIN 

 BLDG E1570 

 APG EA 

 1 DIRECTOR 

 US ARMY RSCH LABORATORY 

 ATTN AMSRD ARL CI OK S FOPPIANO 

 BLDG 459 

 1 DIRECTOR 

 US ARMY RSCH LABORATORY 

 ATTN AMSRD ARL HR MR F PARAGALLO 

 BLDG 459 

 1 DIRECTOR 

 US ARMY RSCH LABORATORY 

 ATTN AMSRD ARL HR SD L PIERCE 

 BLDG 459 

 1 DIRECTOR 

 US ARMY RSCH LABORATORY 

 ATTN AMSRD ARL HR MR T HADUCH 

 BLDG 459

 40 DIRECTOR 

 US ARMY RSCH LABORATORY 

 ATTN AMSRD ARL HR SD T LETOWSKI 

 BLDG 520
39 

NO. OF 

COPIES ORGANIZATION

 2 DRDC TORONTO ARMY LIAISON OFC 

 HUMAN-COMPUTER INTERACTION GROUP 

 ATTN G R ARRABITO STEPHEN BOYNE 

 1133 SHEPPARD AVE WEST 

 PO BOX 2000 

 TORONTO ONTARIO 

 M3M 3B9 CANADA