1,527 articles
Sleep-related hypermotor epilepsy
Sleep-related hypermotor epilepsy (SHE), formerly nocturnal frontal lobe epilepsy, is a rare focal epilepsy with brief stereotyped hypermotor seizures from NREM sleep; renamed in 2016, with genetic and extrafrontal forms.
Sleep-related rhythmic movement disorder
Sleep-related rhythmic movement disorder (SRRMD, RMD) is a sleep-related movement disorder with rhythmic large-muscle movements like head banging and body rocking at 0.5-2 Hz, common and benign in infants, a disorder only when sleep, function, or safety is harmed.
Sleeptalking
Sleeptalking, or somniloquy (ICD-11 MB60), is the production of unaware speech during sleep, a benign parasomnia with 66% lifetime prevalence, more frequent in NREM sleep, with more correct language in REM.
Sleepwalking
Sleepwalking (somnambulism) is an NREM parasomnia causing walking or complex behaviors during deep N3 sleep, mostly in children, with amnesia afterward; genetic, triggered by sleep deprivation, medications, and sleep apnea.
Snowflake vitreoretinal degeneration
Snowflake vitreoretinal degeneration (SVD, OMIM 193230) is a rare autosomal dominant vitreoretinopathy with retinal snowflake deposits, fibrillar vitreous degeneration, early cataract, corneal guttae, and retinal detachment risk, caused by KCNJ13 (Kir7.1) mutations.
Somnolence
Somnolence, also called drowsiness, is the state of wanting to fall asleep; severe, lasting cases are called excessive daytime sleepiness, affecting 4–20% of the population.
Spasm of accommodation
Spasm of accommodation (pseudomyopia, ciliary spasm, ICD-11 9D01.2) is excessive ciliary contraction causing sudden apparent myopia that resolves with cycloplegia; causes include close work, stress, and head trauma.
Spasm of conjugate gaze
Spasm of conjugate gaze (conjugate gaze spasm, CGS): sudden involuntary movement of both eyes in the same direction from extraocular muscle spasm; ICD-10-CM H51.0, ICD-11 9C83.1; includes oculogyric crisis.
Spasm of the near reflex
Spasm of the near reflex (SNR), also called convergence or accommodative spasm, is an intermittent triad of convergent strabismus, pseudomyopia, and miosis, first named by Cogan in 1955; mostly functional, treated with cycloplegics and fogging.
Spasmodic dysphonia
Spasmodic dysphonia, or laryngeal dystonia, is a rare focal dystonia causing involuntary laryngeal muscle spasms, voice breaks, and strained or breathy speech, treated mainly with botulinum toxin injections.
Spasmodic torticollis
Spasmodic torticollis (cervical dystonia): the most common adult-onset focal dystonia, causing involuntary head turning, tilting, and tremor. Treated mainly with botulinum toxin; features geste antagoniste sensory tricks and prominent pain.
Spasmus nutans
Spasmus nutans, a rare benign infantile eye-movement disorder with the triad of asymmetric pendular nystagmus, head nodding, and torticollis; onset 4-12 months, spontaneous remission, but mimicked by optic pathway glioma.
Spastic bilateral cerebral palsy
Spastic bilateral cerebral palsy (ICD-11 8D20.1; SCPE bilateral spastic CP, formerly diplegia/quadriplegia) is spasticity affecting both body sides, about 60% of CP cases, with variable walking ability, gait scissoring, and rehabilitation evidence.
Spastic cerebral palsy
Spastic cerebral palsy, the most common CP type at about 80% of cases, features increased muscle tone with diplegic, hemiplegic, and quadriplegic subtypes; treated with botulinum toxin A, therapy, and selective dorsal rhizotomy.
Spastic diplegia
Spastic diplegia, also called Little's disease or bilateral spastic cerebral palsy, is the most common cerebral palsy subtype, with leg spasticity exceeding arm involvement; treated with SDR, physiotherapy, and rehabilitation.
Spastic hemiplegia
Spastic hemiplegia (ICD-11 MB53.2, ICD-10 G81.1) is one-sided paralysis with involuntary contractions and increased muscle tone, seen as unilateral spastic cerebral palsy in children and post-stroke hemiparesis in adults, affecting the arm more than the leg.
Spastic paraplegia type 2
Spastic paraplegia type 2 (SPG2, X-linked spastic paraplegia 2) is a rare X-linked recessive leukodystrophy caused by PLP1 mutations, allelic with Pelizaeus-Merzbacher disease, causing childhood-onset spastic gait, autonomic dysfunction, and hypomyelination.
Spastic paraplegia type 7
Spastic paraplegia type 7 (SPG7) is a rare autosomal recessive hereditary spastic paraplegia caused by SPG7 gene variants encoding mitochondrial paraplegin, with adult-onset leg spasticity, ataxia, and optic atrophy.
Spastic paraplegia-intellectual disability-nystagmus-obesity syndrome
SINO syndrome (spastic paraplegia-intellectual disability-nystagmus-obesity syndrome, ORPHA:521390, OMIM 617296) is a rare autosomal dominant KIDINS220-related neurodevelopmental disorder with congenital spastic paraplegia, intellectual disability, nystagmus, and obesity.
Spastic paraplegia-optic atrophy-neuropathy syndrome
SPOAN syndrome (spastic paraplegia-optic atrophy-neuropathy syndrome, OMIM 609541) is an autosomal recessive hereditary spastic paraplegia caused by a 216-bp non-coding deletion upregulating KLC2 on 11q13, concentrated in northeastern Brazil, with congenital optic atrophy, infancy-onset spastic paraplegia, and axonal neuropathy.
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.
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.
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.
Speech or language disturbances
Speech or language disturbances (ICD-11 MA80) is a Chapter 21 symptom category covering acquired aphasia, dysphasia, dysarthria, and anarthria, excluding developmental disorders (6A01), autism (6A02), and speech dysfluency (MA81); ICD-10-CM equivalent R47.
Spinocerebellar ataxia type 1
Spinocerebellar ataxia type 1 (SCA1), an autosomal dominant polyglutamine disease from CAG repeat expansion in ATXN1 on 6p22, causing progressive ataxia, dysarthria, bulbar failure; onset third to fourth decade.
Spinocerebellar ataxia type 10
Spinocerebellar ataxia type 10 (SCA10) is a rare autosomal dominant ataxia with seizures caused by an ATTCT pentanucleotide repeat expansion in intron 9 of ATXN10 on chromosome 22q13, found mainly in people of Indigenous American ancestry.
Spinocerebellar ataxia type 11
Spinocerebellar ataxia type 11 (SCA11) is a rare autosomal dominant cerebellar ataxia caused by TTBK2 mutations, classified as ADCA III, with onset at 11-70 years, slowly progressive ataxia, nystagmus, dysarthria, and supportive-only treatment.