Human health and medicine

Spastic peristalsis

Spastic peristalsis (ICD-11 DA21.22), also called distal or diffuse esophageal spasm, is a rare esophageal motility disorder with spastic non-peristaltic contractions causing chest pain and dysphagia, diagnosed by high-resolution manometry.

Spastic tetraplegia

Spastic tetraplegia (痙性四肢麻痺) is four-limb paralysis with velocity-dependent muscle tone from stretch-reflex hyperexcitability; ICD-11 code MB50.1, ICD-10-AM G82.4, seen after cervical spinal cord injury, cerebral palsy, and stroke.

Spastic unilateral cerebral palsy

Spastic unilateral cerebral palsy (USCP, spastic hemiplegia, ICD-11 8D20.0) is one-sided spastic CP, 40–60% of spastic cases, with bilateral weakness, sensory impairment, and CIMT or bimanual therapy.

Spasticity

Spasticity (muscle spasticity) is a velocity-dependent increase in stretch reflexes and muscle tone after upper motor neuron lesions, seen in stroke, spinal cord injury, multiple sclerosis, and cerebral palsy, treated with therapy, baclofen, botulinum toxin, and intrathecal baclofen.

Spatax study

SPATAX (Spastic Paraplegia and Ataxia network) is a European clinical-genetic cohort study of cerebellar ataxias and hereditary spastic paraplegias, database created 2000, hosted at the Paris Brain Institute, coordinated by Alexandra Durr, closed 17 May 2022.

Oct 15, 2026

Spatial audio

Spatial audio is a family of recording and playback techniques that let listeners perceive sound sources in three-dimensional space, most commonly on headphones using head-related transfer functions.

Spatial frequency domain imaging

Spatial frequency domain imaging (SFDI) is a noncontact, wide-field optical technique that projects sinusoidal light patterns onto tissue to map absorption, scattering, hemoglobin, and oxygen saturation, reported in 2005.

Spatial normalization (neuroimaging)

Spatial normalization is a neuroimaging preprocessing method that warps brain scans from different subjects into a common reference space, underpinning voxel-based morphometry and fMRI group analysis.

Spatially fractionated radiation therapy

Spatially fractionated radiation therapy (SFRT) is a radiotherapy technique delivering high-dose peaks separated by low-dose valleys to shrink bulky tumors, including 2D GRID therapy and 3D lattice radiotherapy.

SPECC1L-related hypertelorism syndrome

SPECC1L-related hypertelorism syndrome, formerly Teebi hypertelorism syndrome, is a rare autosomal dominant disorder from SPECC1L gene variants, causing widely spaced eyes and birth defects like omphalocele.

Special interest (autism)

A special interest, also known as a restricted or circumscribed interest, is an intense, highly focused interest found in an estimated 75 to 95 percent of autistic people.

Special K

Special K is a Kellogg breakfast cereal brand behind the Special K Challenge, a two-week diet replacing two daily meals with cereal and milk, claiming six pounds lost; studies show short-term loss averaging about 3.5 pounds, but experts call it unsustainable.

Specimen Handling

Specimen handling covers collecting, preserving, transporting, and storing clinical specimens so they stay stable for accurate lab results; also called specimen collection, it spans the preanalytical phase where 60-70% of laboratory errors occur, governed by CLSI, ISO 15189, and CLIA rules.

Speckle contrast imaging

Speckle contrast imaging, also known as LASCA or LSCI, is a label-free optical technique mapping blood flow in tissue from laser speckle blurring, first published in 1981.

Speckle tracking echocardiography

Speckle tracking echocardiography (STE, 2D/3D strain imaging) tracks myocardial speckles on gray-scale ultrasound to measure strain; GLS is more sensitive and reproducible than ejection fraction, standardized by the EACVI/ASE task force.

SPECT-PROTMA trial

SPECT-PROTMA (NCT05010733) is a single-center pilot randomized trial at Bellvitge University Hospital, Barcelona, comparing periprosthetic bone metabolism and alignment of Exeter V40 versus Müller straight stem cemented hip prostheses with 99mTc-MDP SPECT-CT at 3, 6, 12, and 24 months in 16 patients.

SPECT/CT

SPECT/CT is a hybrid nuclear medicine imaging method combining SPECT functional radiotracer images with CT anatomical images for localization and attenuation correction, first commercialized in 1999.

Oct 15, 2026

Spectinomycin

Spectinomycin (Trobicin) is an aminocyclitol antibiotic produced by the bacterium Streptomyces spectabilis, isolated in 1960 and used as a single intramuscular 2 g dose to treat gonorrhea.

Spectral computed tomography

Spectral computed tomography is an X-ray imaging method that measures attenuation in separate energy ranges, producing iodine maps, virtual non-contrast images, and uric acid stone differentiation.

Oct 15, 2026

Spectral CT

Spectral CT, including dual-energy CT and photon-counting CT, is computed tomography that acquires X-ray attenuation data at two or more energy levels, enabling material decomposition and tissue characterization.

Spectral mammography

Spectral mammography is an X-ray breast imaging technique that measures energy-dependent attenuation to characterize breast tissue, including contrast-enhanced spectral mammography, which uses iodinated contrast to show enhancing lesions.

Spectrin-associated autosomal recessive cerebellar ataxia

Spectrin-associated autosomal recessive cerebellar ataxia, also known as SCAR14, is a rare genetic disease caused by SPTBN2 mutations, marked by developmental delay, intellectual disability, and cerebellar atrophy.

Specular microscopy

Specular microscopy is an ophthalmic imaging technique that photographs the corneal endothelium in vivo, measuring endothelial cell density for diagnosing corneal disease and planning corneal surgery.

Speculum examination

A speculum examination is a physical exam in which a speculum holds open a body canal, most often the vagina, so a clinician can view the cervix and collect specimens.

Oct 20, 2026

Speech Articulation Tests

Speech articulation tests are standardized single-word instruments, such as the Goldman-Fristoe and Arizona scales, that measure accuracy of speech sound production in children, supplemented by connected speech sampling, screening tools, and stimulability testing.

Speech audiometry

Speech audiometry is a clinical hearing test measuring how well a listener detects and understands speech rather than pure tones, using the speech recognition threshold and word recognition score.

Speech Discrimination Tests

Speech discrimination tests, now usually called word recognition testing, measure the percentage of standardized monosyllabic words a listener repeats correctly at suprathreshold levels; rooted in Egan's 1948 phonetically balanced lists and Hahlbrock's German test, they assess speech understanding in quiet and in noise.

Speech disorder

Speech disorder: impairment of articulation of speech sounds, fluency (stuttering), or voice as defined by ASHA; distinct from language disorder. Covers types, prevalence (3-16% of US children), and speech-language pathology treatment evidence.

Speech dysfluency

Speech dysfluency is a disruption of the rhythmic flow of speech, ranging from ordinary hesitations and repetitions to fluency disorders, chiefly stuttering and cluttering, with acquired forms following brain injury.