Sandhoff Disease: An autosomal recessive neurodegenerative disorder characterized by an accumulation of G(M2) GANGLIOSIDE in neurons and other tissues. It is caused by mutation in the common beta subunit of HEXOSAMINIDASE A and HEXOSAMINIDASE B. Thus this disease is also known as the O variant since both hexosaminidase A and B are missing. Clinically, it is indistinguishable from TAY-SACHS DISEASE.Hexosaminidase B: A mammalian beta-hexosaminidase isoform that is comprized of hexosaminidase beta subunits. Deficiency of hexosaminidase B due to mutations in the gene encoding the hexosaminidase beta subunit is a case of SANDHOFF DISEASE.beta-N-Acetylhexosaminidases: A hexosaminidase specific for non-reducing N-acetyl-D-hexosamine residues in N-acetyl-beta-D-hexosaminides. It acts on GLUCOSIDES; GALACTOSIDES; and several OLIGOSACCHARIDES. Two specific mammalian isoenzymes of beta-N-acetylhexoaminidase are referred to as HEXOSAMINIDASE A and HEXOSAMINIDASE B. Deficiency of the type A isoenzyme causes TAY-SACHS DISEASE, while deficiency of both A and B isozymes causes SANDHOFF DISEASE. The enzyme has also been used as a tumor marker to distinguish between malignant and benign disease.Tay-Sachs Disease: An autosomal recessive neurodegenerative disorder characterized by the onset in infancy of an exaggerated startle response, followed by paralysis, dementia, and blindness. It is caused by mutation in the alpha subunit of the HEXOSAMINIDASE A resulting in lipid-laden ganglion cells. It is also known as the B variant (with increased HEXOSAMINIDASE B but absence of hexosaminidase A) and is strongly associated with Ashkenazic Jewish ancestry.Hexosaminidase A: A mammalian beta-hexosaminidase isoform that is a heteromeric protein comprized of both hexosaminidase alpha and hexosaminidase beta subunits. Deficiency of hexosaminidase A due to mutations in the gene encoding the hexosaminidase alpha subunit is a case of TAY-SACHS DISEASE. Deficiency of hexosaminidase A and HEXOSAMINIDASE B due to mutations in the gene encoding the hexosaminidase beta subunit is a case of SANDHOFF DISEASE.Jews: An ethnic group with historical ties to the land of ISRAEL and the religion of JUDAISM.G(M2) Ganglioside: A glycosphingolipid that accumulates due to a deficiency of hexosaminidase A or B (BETA-N-ACETYLHEXOSAMINIDASES), or GM2 activator protein, resulting in GANGLIOSIDOSES, heredity metabolic disorders that include TAY-SACHS DISEASE and SANDHOFF DISEASE.Reaction Time: The time from the onset of a stimulus until a response is observed.Startle Reaction: A complex involuntary response to an unexpected strong stimulus usually auditory in nature.Acoustic Stimulation: Use of sound to elicit a response in the nervous system.Psychomotor Performance: The coordination of a sensory or ideational (cognitive) process and a motor activity.Movement: The act, process, or result of passing from one place or position to another. It differs from LOCOMOTION in that locomotion is restricted to the passing of the whole body from one place to another, while movement encompasses both locomotion but also a change of the position of the whole body or any of its parts. Movement may be used with reference to humans, vertebrate and invertebrate animals, and microorganisms. Differentiate also from MOTOR ACTIVITY, movement associated with behavior.Attention: Focusing on certain aspects of current experience to the exclusion of others. It is the act of heeding or taking notice or concentrating.Photic Stimulation: Investigative technique commonly used during ELECTROENCEPHALOGRAPHY in which a series of bright light flashes or visual patterns are used to elicit brain activity.Aromatherapy: The use of fragrances and essences from plants to affect or alter a person's mood or behavior and to facilitate physical, mental, and emotional well-being. The chemicals comprising essential oils in plants has a host of therapeutic properties and has been used historically in Africa, Asia, and India. Its greatest application is in the field of alternative medicine. (From Random House Unabridged Dictionary, 2d ed; from Dr. Atiba Vheir, Dove Center, Washington, D.C.)Oils, Volatile: Oils which evaporate readily. The volatile oils occur in aromatic plants, to which they give odor and other characteristics. Most volatile oils consist of a mixture of two or more TERPENES or of a mixture of an eleoptene (the more volatile constituent of a volatile oil) with a stearopten (the more solid constituent). The synonym essential oils refers to the essence of a plant, as its perfume or scent, and not to its indispensability.Massage: The systematic and methodical manipulations of body tissues best performed with the hands for the purpose of affecting the nervous and muscular systems and the general circulation.Plant Oils: Oils derived from plants or plant products.Hypnosis: A state of increased receptivity to suggestion and direction, initially induced by the influence of another person.Breast Neoplasms: Tumors or cancer of the human BREAST.Ginger: Deciduous plant rich in volatile oil (OILS, VOLATILE). It is used as a flavoring agent and has many other uses both internally and topically.Stress Disorders, Post-Traumatic: A class of traumatic stress disorders with symptoms that last more than one month. There are various forms of post-traumatic stress disorder, depending on the time of onset and the duration of these stress symptoms. In the acute form, the duration of the symptoms is between 1 to 3 months. In the chronic form, symptoms last more than 3 months. With delayed onset, symptoms develop more than 6 months after the traumatic event.Encyclopedias as Topic: Works containing information articles on subjects in every field of knowledge, usually arranged in alphabetical order, or a similar work limited to a special field or subject. (From The ALA Glossary of Library and Information Science, 1983)Combat Disorders: Neurotic reactions to unusual, severe, or overwhelming military stress.War: Hostile conflict between organized groups of people.Veterans: Former members of the armed services.Stress Disorders, Traumatic, Acute: A class of traumatic stress disorders that is characterized by the significant dissociative states seen immediately after overwhelming trauma. By definition it cannot last longer than 1 month, if it persists, a diagnosis of post-traumatic stress disorder (STRESS DISORDERS, POST-TRAUMATIC) is more appropriate.Life Change Events: Those occurrences, including social, psychological, and environmental, which require an adjustment or effect a change in an individual's pattern of living.Communication Disorders: Disorders of verbal and nonverbal communication caused by receptive or expressive LANGUAGE DISORDERS, cognitive dysfunction (e.g., MENTAL RETARDATION), psychiatric conditions, and HEARING DISORDERS.Stereotyped Behavior: Relatively invariant mode of behavior elicited or determined by a particular situation; may be verbal, postural, or expressive.Autistic Disorder: A disorder beginning in childhood. It is marked by the presence of markedly abnormal or impaired development in social interaction and communication and a markedly restricted repertoire of activity and interest. Manifestations of the disorder vary greatly depending on the developmental level and chronological age of the individual. (DSM-V)Communication Aids for Disabled: Equipment that provides mentally or physically disabled persons with a means of communication. The aids include display boards, typewriters, cathode ray tubes, computers, and speech synthesizers. The output of such aids includes written words, artificial speech, language signs, Morse code, and pictures.Behavior, Animal: The observable response an animal makes to any situation.Motor Activity: The physical activity of a human or an animal as a behavioral phenomenon.Valproic Acid: A fatty acid with anticonvulsant properties used in the treatment of epilepsy. The mechanisms of its therapeutic actions are not well understood. It may act by increasing GAMMA-AMINOBUTYRIC ACID levels in the brain or by altering the properties of voltage dependent sodium channels.Personnel Staffing and Scheduling Information Systems: Computer-based systems for use in personnel management in a facility, e.g., distribution of caregivers with relation to patient needs.New York CityNew YorkInternet: A loose confederation of computer communication networks around the world. The networks that make up the Internet are connected through several backbone networks. The Internet grew out of the US Government ARPAnet project and was designed to facilitate information exchange.Blinking: Brief closing of the eyelids by involuntary normal periodic closing, as a protective measure, or by voluntary action.Sodium Chloride, Dietary: Sodium chloride used in foods.Hypertension: Persistently high systemic arterial BLOOD PRESSURE. Based on multiple readings (BLOOD PRESSURE DETERMINATION), hypertension is currently defined as when SYSTOLIC PRESSURE is consistently greater than 140 mm Hg or when DIASTOLIC PRESSURE is consistently 90 mm Hg or more.Blood Pressure: PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.Rats, Inbred Dahl: Inbred rats derived from Sprague-Dawley rats and used for the study of salt-dependent hypertension. Salt-sensitive and salt-resistant strains have been selectively bred to show the opposite genetically determined blood pressure responses to excess sodium chloride ingestion.Sodium, Dietary: Sodium or sodium compounds used in foods or as a food. The most frequently used compounds are sodium chloride or sodium glutamate.Heart Rate: The number of times the HEART VENTRICLES contract per unit of time, usually per minute.Avoidance Learning: A response to a cue that is instrumental in avoiding a noxious experience.Seals, Earless: The family Phocidae, suborder PINNIPEDIA, order CARNIVORA, comprising the true seals. They lack external ears and are unable to use their hind flippers to walk. It includes over 18 species including the harp seal, probably the best known seal species in the world.Psychophysiology: The study of the physiological basis of human and animal behavior.Sound: A type of non-ionizing radiation in which energy is transmitted through solid, liquid, or gas as compression waves. Sound (acoustic or sonic) radiation with frequencies above the audible range is classified as ultrasonic. Sound radiation below the audible range is classified as infrasonic.Pinnipedia: The suborder of aquatic CARNIVORA comprising the WALRUSES; FUR SEALS; SEA LIONS; and EARLESS SEALS. They have fusiform bodies with very short tails and are found on all sea coasts. The offspring are born on land.Animal Welfare: The protection of animals in laboratories or other specific environments by promoting their health through better nutrition, housing, and care.Auditory Perception: The process whereby auditory stimuli are selected, organized, and interpreted by the organism.