The eHealth industry is evolving rapidly, along with an ever-increasing number of applications. The terminology being used to describe eHealth is also evolving. With this glossary, CTEC seeks to clarify terms currently in widespread use.

Defined simply, Telemedicine and eHealth (TM/eH) are the use of electronic communication technologies as a method of delivering health care, education, and related services. Dissolving barriers such as distance, time, geography, weather, and economics, TM/eH applications are designed to bring services to clients rather than clients to services. The common goal of any TM/eH application is to increase access and ease of health care, especially for rural and underserved populations.

When data rather than clients are moved, health resources extend their reach: the arm of specialty care extends further, access to better informed primary care services increases, and there is greater chance for utilization of medical education and training by medical professionals and community members. Because TM/eH systems increase access to specialty care and education as well as communication with larger, more sophisticated hospitals, rural doctors and clinicians are able to maintain a working relationship with their peers, and can increase their professional and social connections to the medical realm and its information flow.

Essentially, TM/eH systems are designed to increase the reach, as well as reduce both the time and cost, of medical consultations and care by bringing both preventative and maintenance-based information and services to the patient.

Telemedicine
The use of telecommunications and information technologies for the provision of healthcare at a distance. New methods continue to evolve over time, but this includes real time videoconferencing as well as store and forward methodologies.

Real Time
In Telemedicine terms, conducting an encounter or consultation where both parties are available and interacting simultaneously. Real Time Telemedicine is generally conducted via full motion videoconferencing.

Store and Forward
A Telemedicine/eHealth encounter or consult that relies on the asynchronous transfer of still digital images of a patient, or clinical data, such as blood glucose levels or electrocardiogram measurements, from one site to another for the purpose for rendering a medical opinion or diagnosis. Common types of store and forward services include radiology, pathology, dermatology, ophthalmology, and wound care.

Asynchronous Communication
A mode of communication where the transfer takes place over a period of time, or in separate time frames, not requiring the transmission to take place simultaneously. Examples include e-mail or store and forward Telemedicine/eHealth.

Synchronous Communication
A mode of communication where the transfer takes place simultaneously. Examples include real time videoconferencing or standard telephony.

Telecommunications
Transmission and reception of voice, video, or other data over a distance. A telecommunications system has several components: a transmitter (electronic device), a transmission medium (e.g., wire-based Telco or LAN, wireless antenna, satellite), and generally a specific channel (e.g., radio frequency, phone number, IP address). Telecommunications can be point-to-point, multipoint, or broadcast (one way transmission from a sender to multiple receivers).

Bandwidth
A measure of the information-carrying capacity of a communications channel. The higher the bandwidth (the larger the “pipe”), the greater the amount of information or data that can be transmitted in a given time period. Bandwidth is usually measured in Kilobits (Kbps) or Megabits per second (Mbps). Higher levels of bandwidth allow video and audio data to be transmitted more rapidly from point to point, allowing the capture and transmission of movement with less “jerkiness.”

Broadband
In networking terminology, a telecommunications medium capable of transmitting multiple data signals simultaneously. The term broadband is also used to describe media that transmit data at a high rate, generally comparable to T1 or better, and occasionally as a synonym for DSL. Television, microwave, and satellite telecommunications are examples of broadband media.

Digital Subscriber Line (DSL)
A dedicated broadband technology that uses the ubiquitous twisted pair copper wire connecting most homes and businesses today through the public telephone system to provide connectivity at relatively high speeds. DSL accomplishes this by dividing the existing telephone frequencies so that voice and data may be carried simultaneously without interference. Unlike a dial-up connection, DSL is always available. There are several different implementations available. The most common is called Asymmetric or Asynchronous (ADSL). An ADSL connection is characterized by a high-speed downstream channel, and somewhat lower speed upstream channel. Synchronous DSL is also available for business use. Distance from the subscriber site to the Telco’s Central Office is the main determinant of the actual performance of a DSL connection.

Integrated Services Digital Network (ISDN)
A dial-up digital connectivity medium used commonly for videoconferencing. ISDN can transmit voice, data, and video simultaneously over a connection. Since ISDN services are used on demand by dialing another ISDN-based device, per-minute charges accumulate at a contracted rate and then are billed to the site placing the call. This service is analogous to using the dialing features associated with a long distance telephone call – whoever dials pays the bill.

Plain Old Telephone Service (POTS)
The ubiquitous, partially analog phone system currently in public use worldwide. Also known as the Public Switched Telephone Network (PSTN). Although a relatively low bandwidth medium, POTS is sometimes a suitable medium for Telemedicine, based on ease of access and low cost. POTS videophones and telemetry devices are often used in Telehomecare.

Coder-Decoder (CODEC)
A device, either hardware or software based, that encodes analog video and audio signals to digital video and audio, and vice versa. CODECs typically compress the digital code to conserve bandwidth and increase effective throughput.

Gatekeeper
A device that manages videoconferencing traffic and address translation within an IP-based (H.323) network, often for a specific zone. This device is useful in eliminating bottlenecks, enhancing quality of service, and simplifies addressing of videoconferencing endpoints.

Gateway
A device that provides protocol translation between H.320 (ISDN) and H.323 (IP) networking environments, allowing endpoints using ISDN to interconnect with endpoints videoconferencing over IP.

Multiplexer (MUX)
A device that combines multiple inputs (such as ISDN PRI channels or ISDN BRI lines) into an aggregate signal to be transported via a single transmission path. For example, a MUX can be used to achieve a speed of 384 Kbps for effective videoconferencing by combining three pairs of BRI lines into a single data circuit.

International Telecommunications Union (ITU) Recommendations
Now an agency of the United Nations, the ITU was originally founded in 1865 to standardize telegraphy. The ITU’s Telecommunication Standardization Sector (ITU-T) publishes a wide range of “Recommendations” (i.e. standards) relating to telecommunications and videoconferencing. Equipment based on these standards allows successful conferencing regardless of platform or manufacturer. The ITU-T standards most familiar to videoconferencing users are found in the H-series, “Audiovisual and Multimedia Systems,” (primarily for control of videoconferencing over ISDN, IP, etc.), the G-series, “Transmission Systems and Media, Digital Systems and Networks,” (primarily for control of audio transmission) and the T-series, “Terminals for Telematic Services” (primarily for control of data collaboration and similar features). See also http://www.itu.int/ITU-T/index.html.

H.320
The ITU technical standard for videoconferencing that allows different equipment to interoperate via ISDN connections.

H.323
The ITU technical standard for videoconferencing that allows different equipment to interoperate via TCP/IP.

Continuous Presence
In multipoint conferencing, a mode that displays multiple participants in a portion of the screen at all times. Although an effective format for discussion, continuous presence is not generally the ideal mode for lectures, as any presentation graphics will be limited to a segment of the available viewing area.

Endpoint
A terminal used to make or receive a videoconferencing call. Calls originate and terminate at endpoints.

Hub Site
In Telemedicine, the location from which specialty or consultative services originate.

Multipoint Videoconference
Videoconference with three or more participants. A multipoint conference generally requires the use of an MCU (or equipment with built-in multipoint capability). During a multipoint conference, there are two modes available to present the participants. In a continuous presence videoconference, all participants can be seen at the same time on the far end monitors. Microphones at all sites can be active, which may lead to extraneous noises and interruptions. This mode is not the best choice if data is to be displayed (e.g., via document camera, whiteboard, etc.) as the presentation will be limited to a portion of the screen. Conversely, in the voice activated mode, only the participating site that produced the most recent audio input will be visible. Other sites must ensure their microphones are muted to prevent inadvertently switching the video away from the intended speaker. Where several speakers take turns in voice activated mode, they must realize there is a tangible delay as the view switches from one site to the next.

Point to Point Conference
The classic videoconferencing mode consisting of two participants connected directly. This is the most common usage for patient encounters or provider consultations.

Presentation Mode
Videoconferencing mode in which one site (e.g., a lecturer) is continuously displayed to all endpoints. Sometimes also called broadcast or lecture mode.

Presenter (Patient Presenter)
Telemedicine encounters require the distant provider to perform an exam of a patient from many miles away. In order to accomplish that task, an individual with sufficient clinical background and training in the use of Telemedicine equipment must be available at the originating site to “present” the patient, manage the cameras, and perform any “hands-on” activities to successfully complete the exam.

Spoke Site
The remote site where the patient is presented during a Telemedicine encounter, or where the professional requesting consultation with a specialist is located.

Electronic Health Record (EHR)
An electronic record composed of health information regarding an individual patient that exists as part of a complete system designed to provide access to, and management of, such information. The EHR is developed and managed by the health facility or provider. The term Electronic Health Record has largely replaced the older “Electronic Medical Record.”

Health Level Seven Messaging Standard (HL7)
A series of communications protocol standards for the transmission of health information. HL7 messaging allows various applications and medical devices to successfully interact and exchange information. See also http://www.hl7.org/.

Kiosk (Electronic Kiosk)
A purpose-built computer system designed to allow access to a specific set of programs or search sites. An electronic kiosk is generally designed with a sturdy housing to prevent theft or tampering, and withstand unattended public use. The system uses software operating in “kiosk mode,” which restricts access to carefully defined functionality, whether a search for health information, assistance in completing forms, etc. Kiosks have been used to provide access to health information, online applications for state programs such as health insurance (i.e. Medi-Cal or Healthy Families in California), or to generate vouchers for specific treatments such as flu shots.

National Health Information Infrastructure (NHII)
An initiative of the Department of Health and Human Services to improve the state of health information technology in the U.S. One vision for the future of this initiative involves work towards a National Health Information Network (NHIN), to help face the significant challenges of inconsistent quality and rising costs in U.S. healthcare, and integrate Regional Health Information Organizations as they develop throughout the country. See also http://www.hhs.gov/healthit/.

Personal Health Record (PHR)
A longitudinal patient-maintained record of individual health history. The PHR is generally a consumer product that can be accessed, and in a growing number of cases, populated, by the patient. The intent of many such systems is to allow the PHR to be either owned or at the least shared by the patient. The PHR is meant to move along with the patient no matter where they are located or what health plan or organization they are connected to.

Picture Archiving and Communications System (PACS)
A digital system for the acquisition, storage, transmission and display of images from various sources, including X-ray, CT, MRI, and ultrasound. PACS generally include optical storage servers, high resolution displays, printers, and other functionality.