Telehealth Glossary

Telemedicine/Telehealth Terms:

Distant Site: The Centers for Medicare and Medicaid Services (CMS) define the distant site as the telehealth site where the provider/specialist is seeing the patient at a distance or consulting with a patient’s provider. Others common names for this term include – the hub, specialty site, provider/physician site and referral site.

Digital Camera (still images): A digital camera is typically used to take still images of a patient. General uses for this type of camera include dermatology and wound care. This camera produces images that can be downloaded to a personal computer (PC) and sent to a provider/consultant over a network.

Document Camera: A camera that can display written or typed information (e.g., lab results), photographs, graphics (e.g., EKG strips) and in some cases X-Rays.

Originating Site: CMS defines originating site as the site where the patient and/or the patient’s physician is located during the telehealth encounter or consult. Other common names for this term include – spoke site, patient site, remote site, and rural site.

Patient Examination Camera (video): This is the camera typically used to examine the general condition of the patient. Types of cameras include those that may be embedded with set-top videoconferencing units, handheld video cameras, gooseneck cameras, camcorders, etc. The camera may be analog or digital depending upon the connection to the videoconferencing unit.

Presenter (Patient Presenter): Telehealth encounters require the distant provider to perform an examination of a patient or client from many miles away. In order to assist the provider, an individual at the patient (originating) site is often needed to coordinate tasks, such as use of the equipment or obtaining vital signs. Many providers also prefer that a staff with a clinical background (e.g., LPN, RN, etc) at the patient site “presents” the patient, manage the cameras and perform any “hands-on” activities to successfully complete the examination. For example, a neurological diagnostic exam usually requires a nurse capable of testing a patient’s reflexes and other manipulative activities. It should be noted that in certain cases (e.g., some dermatology or mental health encounters) a presenter with a clinical background is not always necessary, because the encounter may only require camera management skills. Sometimes, especially for psychiatric or other medically oriented examinations, the clinical staff will attend the entire session.

Store and Forward (S&F) or Asynchronous Telemedicine: S&F is a type of telehealth encounter or consult that uses still digital images of a patient for the purpose of rendering a medical opinion or diagnosis. Common types of S&F services include radiology, pathology, dermatology, and wound care. Store and forward also includes the asynchronous transmission of clinical data, such as blood glucose levels and electrocardiogram (ECG) measurements, from one site (e.g., patient’s home) to another site (e.g, home health agency, hospital, clinic). Recent work in telemental health has assessed the reliability of conducting and recording a clinical examination of a patient at the patient sites at one point in time and then forwarding the recording to a psychiatrist for review at a later time.

Universal Service Administrative Company (USAC): The Universal Service Administrative Company administers the Universal Service Fund (USF), which provides communities across the country with affordable telecommunication services. The Rural Health Care Division (RHCD) of USAC manages the telecommunications discount program for health care.

Telecommunication/Networking Terms:

Analog: Information, electronic or otherwise, that is created and transmitted as a continuous stream, as opposed to small digital packets. Most home telehealth devices require the use of analog lines.

Asynchronous: This term is sometimes used to describe store and forward transmission of medical images or information because the transmission typically occurs in one direction in time. This is the opposite of synchronous (see below).

Bandwidth: The capacity of an electronic transmission to transmit data per unit of time. The higher the bandwidth, the more data that can be transmitted. Bandwidth is typically measured in kilobits per second (kbps) or megabits per second (Mbps). Standard telephones are low bandwidth devices. Cable television and T-1 lines are bandwidth devices.

Baud rate: The ring rate or line power of the telephone line providing service into a given structure (e.g., home). Most home telehealth devices require a minimum baud rate of 14,000 to make successful video capture. However, the lower the baud rate, the more likely it is that disconnections will occur.

Broadband: Communications (e.g., broadcast television, microwave, and satellite) capable of carrying a wide range of frequencies. Broadband refers to transmission of signals in a frequency-modulated fashion, over a segment of the total bandwidth available, thereby permitting simultaneous transmission of several messages.

CODEC: Acronym for coder-decoder. This is the videoconferencing device (e.g., Polycom, Tandberg, Sony, Panasonic, etc) that converts analog video and audio signals to digital video and audio code and vice versa. CODECs typically compress the digital code to conserve bandwidth on a telecommunications path.

Component video: This type of video yields better image quality, higher lines of resolution, and better color.

Compressed video: Video images that have been processed to reduce the amount of bandwidth needed to capture the necessary information so that the information can be sent over a telephone network.

Digital: Information coded in numerical values (bits). Digital data streams are less susceptible to interference than analog streams. They can be more easily integrated with other data streams such as voice/video/data.

Digital camera: Captures images (still or motion) digitally and does not require analog to digital conversion before the image can be transmitted or stored in a computer. Most home telehealth equipment uses digital video cameras.

Digital Imaging and Communication in Medicine (DICOM): A standard for communications among medical imaging devices.

DS1 (T1): A digital carrier capable of transmitting 1.544 Mbps of electronic information. The general term used for a digital carrier available for high-value voice, data, or compressed video traffic.DS3 (T3): A carrier of 45 Mbps. Many systems use only a fraction of this transmission capability: “fractional T1 line.”

Electronic Data Interchange (EDI): The sending and receiving of data directly between trading partners without paper or human intervention.

Encryption: A mathematical transposition of a file or data stream so that it cannot be deciphered at the receiving end without the proper key. Encryption is a security feature that assures only the appropriate parties participates in a video visit or data transfer.

Firewall: A computer connected both to the Internet and a local network (e.g.,a hospital) that prevents the passing of Internet traffic to the internal network. Provides an added security layer.

Frame rate: Frames per second (fps) displayed on a video unit. A frame rate of 25-30 is considered full motion. A lower frame rate can be associated with a noticeably “jerky” motion on the screen. Slower frame rates may be inadequate for some assessments such as gait and balance activities.

H.320: This is the technical standard for videoconferencing compression standards that allow different equipment to interoperate via connections through T1 lines or an Integrated Services Digital Network (ISDN).

H.323: This is the technical standard for videoconferencing compression standards that allow different equipment to interoperate via the Internet Protocol (see below).

H.324: This is the technical standard for videoconferencing compression standards that allow different equipment to interoperate via Plain Old Telephone Service (POTS).

Health Level 7 (HL7) Data Communications Protocol: A standard interface between hospital information systems. Defines standards for transmitting billing, hospital census, order entries, and other health-related information.

Interactive video/television: This is analogous to videoconferencing technologies that allow for two-way, synchronous, interactive video and audio signals for the purpose of delivering telehealth, telemedicine or distant education services. It is often referred to by the acronyms – ITV, IATV or VTC (video teleconference).

Internet: A loose gathering of thousands of computer networks forming an enormous worldwide area network.

Intranet: A “private Internet”, or internal web that employs certain communication protocols used over the Internet. The Intranet may be linked to the public Internet through tightly managed gateways.

Integrated Services Digital Network (ISDN): This is a common dial-up transmission path for videoconferencing. Since ISDN services are used on demand by dialing another ISDN based device, per minute charges accumulate at some 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.

ISDN Basic Rate Interface (BRI): This is an ISDN interface that provides 128k of bandwidth for videoconferencing or simultaneous voice and data services. Multiple BRI lines can be linked together using a multiplexer (see below) to achieve higher bandwidth levels. For instance, a popular choice among telehealth networks is to combine 3 BRI lines to provide 384k of bandwidth for video-conferencing. It should be noted that BRI services are not available in some rural locations. One should check with their telecommunications providers on the availability of BRI service before ordering videoconferencing equipment that uses this type of service.

ISDN Primary Rate Interface (PRI): This is an ISDN interface standard that operates using 23, 64k channels and one 64k data channel. With the proper multiplexing equipment the ISDN PRI channels can be selected by the user for a video call. For instance if the user wants to have a videoconference at 384k of bandwidth then they can instruct the multiplexer to use channels 1 through 6 (6 x 64k = 384k). This is important because the user typically pays charges based on the number of 64k channels used during a videoconference. The fewer channels used to obtain a quality video signal the less expensive the call.

Internet Protocol (IP): IP is part of the protocols describing the software that tracks the Internet address of outgoing and incoming messages. Most of today’s videoconferencing devices have the capability to use IP as a video protocol (see H.323 above). The IP address of a videoconferencing system is its phone number.

Local Area Network (LAN): A computer network linking computers, printers, servers, and other equipment within a system. Can support audio, video, and data exchange.

Modem: Modulator/Demodulator. Enables transmission of digital data over standard analog phone lines and cable video systems.

Multiplexer (MUX): A device that combines multiple inputs (ISDN PRI channels or ISDN BRI lines) into an aggregate signal to be transported via a single transmission path.

Multipoint Control Unit (MCU): A device that can link multiple videoconferencing sites into a single videoconference. An MCU is also often referred to as a “bridge”.

Network: An assortment of electronic devices (computers, printers, scanners etc,) connected by wires or wireless for mutual exchange of digital information.

PBX: Private Branch Exchange (a.k.a. the switchboard) is a telephone system (i.e., switchboard, telephone lines, switching computer) within a VHA facility/campus that switches internal phone lines between VHA users, who actually share a certain number of external (outside) phone lines. Having a PBX saves money by reducing the number of lines required to connect all VHA facility telephones to the telephone company’s central office.

Peripheral devices: Attachments to videoconferencing systems to augment their communications or medical capabilities. Examples include electronic stethoscopes, blood pressure cuffs, glucometers, and weight scales.

Pixel: A picture cell with specific color or brightness. The more pixels an image has, the more detail or resolution it can display.

POTS: Acronym for Plain Old Telephone Service. The analog, public-switched telephone network in common use throughout the world. Most home telehealth products rely on POTS.

Real time: Sends and receives audio/video/data simultaneously, without more than a fraction of a second delay.

Resolution: The level of detail that can be captured or displayed. For video displays resolution is measured in pixels X lines X bit depth.

Router: This is a device that interfaces between two networks or connects sub-networks within a single organization. It routes network traffic between multiple locations and it can find the best route between any two sites. For example, PCs or H.323 videoconferencing devices tell the routers where the destination device is located and the routers find the best way to get the information to that distant point.

Store-and-forward: captured audio clips, video clips, still images, or data that are transmitted or received at a later time (sometimes no more than a minute).

Switch: A switch in the videoconferencing world is an electrical device that selects the path of the video transmission. It may be thought of as an intelligent hub (see hub above) because it can be programmed to direct traffic on specific ports to specific destinations. Hub ports feed the same information to each device.

Synchronous: This term is sometimes used to describe interactive video connections because the transmission of information in both directions is occurring at exactly the same period.

Telehealth and Telemedicine: Telemedicine and telehealth both describe the use of medical information exchanged from one site to another via electronic communications to improve patients’ health status. Although these terms are evolving to be more specific, telemedicine is sometimes associated with direct patient clinical services and telehealth sometimes associated with a broader definition of remote healthcare that may include other health related services, including health education, patient-accessed information.

Thumbnail: Miniature pictures of images using very small, low-resolution data files. These download for display very quickly.

Transmission control protocol/Internet protocol (TCP/IP): A communications protocol governing data exchanged on the Internet

Transmission rate: Amount of information/unit of time that a technology such as POTS or digital ISDN phone line, satellite or wireless technology, or local area network can transmit.

Wide area network (WAN): Wider in geographic scope than a LAN. Provides digital communications (voice/video/data) over switched or un-switched networks.