Technical Report AMI-MU-007:

Access to Teleconferencing Technologies

Authors: Jason Foil, B.B.E., Randy Will

Coordinating Editor: Jack Winters, Ph.D.

Laboratory: Telerehabilitation and Functional Performance Laboratory

Current Version: 1.01 (June 2006), (Version 1.0 was July 2003)

Table of Contents

Note: This technical report, including the table of teleconferencing products, is under revision and expansion during the summer of 2006, and will soon be updated.

Executive Summary

With the many progressions in medical technology and the demands by patients for enhanced access, telehealth has become a veritable melting pot for different disciplines and technologies.  An important consideration is how the medical device industry can utilize technologies, especially those currently developed, to allow persons with disabilities more equitable access.  One advantage of videoconferencing technologies is that they are inherently multimodal, thus potentially providing alternative modes for healthcare encounters. The use of videoconferencing equipment for telehealth for applications such as home telehealth, telepsychiatry, rural healthcare advancement, and elderly healthcare has been and continues to be a current topic for research and innovation.

This review is concerned with how these products can be used in their current state by those who have disabilities.  The most common aspects that will be looked at in this assessment are how difficulties relating to visual impairments, hearing impairments, lack of speech, and motor deficiencies are compensated by adjusting the current products without changing their essential design.

The products reviewed were not designed with disabilities in the fore mind of the planner.  However, the products can still be evaluated with the specific mindset of how they can be utilized by and for people with disabilities, especially as related to healthcare.  For instance, some products allow the main video feed to be displayed on a secondary screen.  One can use a large screen television with high definition to supplement for a loss of partial eyesight, allowing one to now see the screen without major complications.  While most of these products are fairly usable, one hope of this review is that it provides information that can be used to improve on current designs of videoconferencing and telehealth equipment and procedures so as to enable higher access for people with disabilities, both to healthcare and to employment opportunities in the health professions.

Background

One aspect of telehealth is the use of interactive videoconferencing technology by the medical community.  Many health professions, such as dermatology, correctional psychiatry, ophthalmology, rheumatology, applied health and clinical nursing, have found many clinical uses for videoconferencing equipment.

The three different standards used in this review are H.324, H.323, and H.320; there are many sources for review of these standards, including from the perspective of telerehabilitation (Winters, 2003). Key principles behind having such standards are compliance and interoperability.  When looking at products, it should always be checked that it is compliant with the standard that it is using.  In being so, it will be able to connect to any other unit that is also compliant, including different brands.  The standards also dictate the minimum ability that any aspect related to the quality of the product must meet, which helps to create uniformity among the products in the standard.  Yet, one of the most important pieces is that a certain amount of bandwidth must be dedicated to audio, which causes video to be the first segmentation of the total bandwidth to go out if the bandwidth suddenly is lessened.  In doing so, one is always able to retain an audio conversation with the remote site.

The International Telecommunication Union's (ITU's) H.320 standard is applied mostly to dedicated circuit-based switched network (point-to-point) connections of moderate or high bandwidth. Connections made with H.320 compliant products use ISDN (integrated services digital network) lines or fractionated high bandwidth T1 lines.  With ISDN, multiple digital phone lines must be installed, as a single-line ISDN connection requires two phone lines to get to a rate of 128 Kbits per second (128 Kbps).  The industry norm is to use 3 ISDN lines (i.e. connect at 3x128Kbps = 384 Kbps), which is also a quarter of a 1.44 Gbps T1 line. This normally gives near-TV level quality (30 fps, CIF or 4CIF image).The optional T.120 standard includes a shared whiteboard, chat, and file transfer. In addition to local and remote control of zoom/pan/tilt, there are connection protocols, prioritization for bandwidth distribution between audio, video and data (audio has highest priority), and specifications for the structure of multipoint connections. Virtually all of the newer H.320 products are also H.323 compliant.

The ITU's H.324 protocol, intended for "videophones" that use POTS (plain old telephone service) phone lines (available in 97% of US households), is the standard that uses normal analog telephone lines for communication. It was adopted by many videophones and home telehealth products, especially during the late 1990's and early 2000's.  Much like a computer modem, POTS units cannot exceed a connection rate higher than 56 Kbps (with about 33 Kbps the practical maximum), and is thus considered to be low-bandwidth.  Since communication is by standard phone lines, it is also the most commonly found medium in households.  These are the least expensive of all of the videoconferencing technologies taken into account here.  Being the least expensive, they also on average have the least number of options and access to change the usability. Most devices function as a stand-alone appliance with simple set-up, and have an interactive on-screen display. Control operations are typically through either a telephone keypad or remote control. Most support both NTSC and PAL formats and auto-answer features. The maximum frame rate is 15 fps, typically with a selectable range from about 1-15 fps. Typically the number of pixels is CIF (354x288) or QCIF (176x144), and most systems enable users to see both feeds (e.g., via picture-in-picture). Most employ low-delay full duplex audio with echo cancellation (using G.723.1, a fairly aggressive speech codec at 5.3 or 6.3 Kbps), and the H.263 or H.264 video codecs.

The third class of standards are based on conferencing over the packet-based circuits, often called Internet Telephony. This refers to real-time transport of multimedia telephone calls over the Internet. When only voice is transferred, it is often called Voice over IP (VoIP).  Next to POTS, IP communication is the second most common medium in households, and with increased penetration of DSL and Cable Modem technologies, IP-based teleconferencing is growing. But over the Internet there is not guaranteed quality of service, which is an issue for some helathcare applications. One of the two key standards is H.323, which "describes terminals and other entities that provide multimedia communications services over Packet Based Networks (PBN) which may not provide a guaranteed Quality of Service. H.323 may provide real-time audio, video and/or data communication" (from ITU-T Recommendation H.323 V4). The other key standard, SIP (Session Initation Protocol), is "an application layer signaling protocol that defines initiation, modification and termination of interactive, multimedia communication sessions between users." (IETF RFC 2543 SIP). It consists of a user agent that initiates, receives and terminates calls (with client/server model) and a proxy server that relays call signaling, a SIP redirect server, and a SIP registrar that accepts requests and maintains user's whereabouts. Advantages of IP-based conferencing include low costs for those who already have computers (e.g., webcams are as cheap as $20, free embedded software such as and Microsoft's client-side H.323-based Netmeeting and MSN Messenger packages, and their SIP-based Windows Messenger product). The speed of IP is not very constant, however, since it depends on the speed at which one is able to communicate through their Internet/Ethernet.  IP can also be computer based, which is why there is such a large mass of software available.  Adduitionally, multimedia can be integrated into web-based healthcare services. The technology boom is making IP products cheaper and cheaper as the quality increases, vastly improving their capabilities.

The accessibility by persons with disabilities comes into play in several fashions.  Take the example of a person who has a tremor.  The said tremor causes a loss of fine and gross motor control of their hand.  When trying to operate a remote, the person is not able to press the buttons with any degree of accuracy or precision.  This greatly hinders their ability to dial phone numbers and control video settings during a call using the remote.  Some units allow the use of a phone to control the video system.  This can be easier to use by a person with tremor, because a large button phone can be used as the medium for controlling the videoconference.  Some of the high priced units have far-site control, which means that the person with whom you are conferencing can control your camera and features if they have the proper equipment.  Although this takes the control out of the direct hands of the person with tremor, it could still be easier for them to give directions to the person on the screen instead of do the physical work themselves.

Product Table

Product Survey

The Product Table provides a brief summary of teleconferencing equipment currently on the market that has been (or could be) used for healthcare applications.  The products are listed with design elements that are relevant to this review, including control features.  Many of the columns are design specifications as documented by the manufacturer.  The last few columns are the ones relating to persons with disabilities.  A scale was devised from 0 to 2, with 0 being that the product does not allow for equal usability by those with disabilities, 1 being that is partially allows, and 2 being that is allows full and equal use.  The cost reflects the worth as stated by the manufacturer, and not necessarily the price currently on the market.
There are several aspects of the tables that deserve extra attention.  The first, and probably one of the most important, is that ability to have alternate/peripheral outputs and inputs on the videoconferencing system being used.  The main reason for this is that with video outputs, the screen size and quality is up to the cost directive of the user.  For instance, the TeleVyou 511 by Leadtek is an H.320 standalone unit with a 5.0 inch built-in LCD display.  For those with no eyesight and even partial eyesight, the small size of the screen is a major fallback of the product.  However, the TeleVyou 511 gives the user the ability to use a second monitor that shows the same video output as the LCD display.  The user could then purchase a 36-inch plasma television, which would be much better to use for those whom have visual impairments. 

However, those who have no vision are left with little choice when quality of product is of concern.  Of all of the currently investigated products, none has the inherent ability to output Braille.  For a blind person, unless IP-based text messaging is used, sitting in a videoconference is no different than sitting in front of the practitioner face-to-face, or even just being on the telephone. 

Product Evaluation

To be completed.

Recommendations for R&D

It is recommended that the RERC-AMI's D3 Emerging and Accessible Healthcare Technologies continue to pursue work in this area.

Acknowledgment

This work is supported by the Rehabilitation Engineering Research Center on Accessible Medical Instrumentation, funded by the National Institute on Disability and Rehabilitation Research, U.S. Department of Education Grant #H133E020729. All opinions are those of the authors.

References

  1. Winters, J.M. (2003).  Telerehabilitation Research: Emerging Opportunities.  Ann. Rev. Biomedical Engineering, 4: 287-320.