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Onychomatricoma: Epidemiological and clinical fndings in a large series of 30 cases quality advair diskus 250 mcg asthma symptoms gerd. Superfcial acral fbromyxoma: A clinicopathologic and immuno histochemical analysis of 37 cases of a distinctive soft tissue tumor with a predilection for the fngers and toes generic advair diskus 500mcg with amex asthma zinc. Keloid formation after syndactyly reconstruction: Associated conditions discount advair diskus 250mcg on line asthmatic bronchitis 39, prevalence cheap advair diskus 250mcg without a prescription asthma graph, and preliminary report of a treatment method. Keloid formation after syndactyly release in patients with associated macro dactyly: Management with methotrexate therapy. Not all granular cell tumors show Schwann cell differen tiation: A granular cell leiomyosarcoma of the thumb, a case report. Plexiform schwannoma (neurilemmoma) associated with macro dactyly: A case report. Insights into enchondroma, enchondromatosis and the risk of secondary chondrosarcoma. Giant cell tumor of the distal phalanx of the biphalangeal ffth toe: A case report and review of the literature. An isolated granular cell tumour of the thumb pulp clinically mimicking a glomus tumour. Clinical profle of Langerhans cell histiocytosis at a tertiary centre: A prospective study. Painful glomus tumour of the thumb in an 11-year-old child with neurofbro matosis 1. Glomus tumours in the long fnger and in the thumb of a young patient with neurofbromatosis-1 (Nf-1). Skin lesions in children with tuberous sclerosis complex: Their prevalence, natural course, and diagnostic signifcance. Multiple ungual fbromas as an only cutaneous manifestation of tuberous scle rosis complex. Shave and phenolization of periungual fbro mas, Koenen’s tumors, in a patient with tuberous sclerosis. Successful treatment of subungual fbromas of tuberous sclerosis with topical rapamycin. Congenital hypertrophy of the lateral nail folds of the hallux: Clinical features and follow-up of seven cases. Ungual pain develops in the context of a unique anatomic confguration: the absence of subcutaneous tis sue between the plate and the underlying bony phalanx, added to the presence of fbrous collagenic fbers frmly attaching the plate to the terminal phalanx, thus making the subungual space virtual, without possible dilation. Traumas Nail bed injuries are the commonest pediatric hand injuries presented to the emergency department. These injuries are often underestimated and, consequently, delegated to the most junior and inexperienced staff. Too often, patients ask for help for late dystrophies resulting from inadequate manage ment of a nail trauma in early childhood. This painful experience still remains too frequent in toddlers for a home accident that can be often prevented by the acquisition of cheap specifc protective devices. There is still no consensus regarding the optimal mode of managing the acute trau matic subungual hematoma in the hand. There is no difference in cosmetic outcome when comparing nail bed repair with simple decompression. Bedside ultrasound has become increasingly important to identify and characterize the for eign body before removal and then to evaluate for any residual foreign body after removal. A few days after its removal, she developed a periungual swelling, with loss of the cuticle and xanthonychia on two nails that also stopped growing. It results from direct or indirect trauma to the cuticle or nail fold allowing penetration of pathogens, such as Staphylococcus aureus and hemolytic Streptoccocus. Bacterial acute paronychia should not be confused with parakeratosis pustulosa, affecting most commonly the thumb or the index fnger, typically in girls around the age of 7 years and considered as a symptom of an infammatory disease of the nail apparatus such as psoriasis, contact dermatitis, or atopic dermatitis. Specifc diagnosis can be made by polymerase chain reaction, culture,28 or direct fuorescent antibody testing. Herpetic whitlow is often misdiagnosed as a bacterial felon and thus improperly treated. Most com monly they are located on the nail folds (proximal and lateral) but sometimes extend to the nail bed with associated onycholysis (Figure 16. Although spontaneous regression is reported in 30% of the cases, treatment is advisable when the lesion causes pain and to avoid spreading of the same. Thirteen children needed oral antibiotic therapy because of bacterial superinfections. It has been attributed to an asynchronism between the growth of the nail plate and that of the soft tissues. The only series on the follow-up of patients demonstrates a spontaneous or partial improvement in 40%, no improvement in 30%, and worsening in 30% of cases. With time, granulation tissue may develop with concomitant oozing, bleeding, and secondary infection (Figure 16. The condition regresses spontaneously in the newborn as the refex disappears around the fourth month. It is characterized by a triad associating arrest of the growth of the nail plate, proximal paronychia, and xanthonychia. It mostly affects women (>80%) and the great toenails (>90%) confrming the probable role of poorly ftting, or tight-toed footwear. This lifts up the proximal nail fold that becomes infamed and irritated from the proximal stacked thin sharp nails, resulting in paronychia. Another clue for the diagnosis is the shortening of the distal nail bed due to the excessive pressure of the distal plate onto the bed and the lifting of the proximal part of the plate from the successive superposed nails. Primary or idiopathic chilblains is more frequent in children, compared to the secondary form, associated with connective tissue disease and hematologic disorders.

Disc swelling due to order 500 mcg advair diskus otc asthmatic bronchitis and pneumonia oedema must be distinguished from pseudopapil loedema buy 500mcg advair diskus otc asthma specialist, elevation of the optic disc not due to discount 500 mcg advair diskus amex asthma questionnaire for doctors oedema generic advair diskus 100mcg on-line asthma treatment image, in which the nerve bre layer is clearly seen. The clinical history, visual acuity, and visual elds may help determine the cause of disc swelling. Recognized causes of disc swelling include • Unilateral: Optic neuritis Acute ischaemic optic neuropathy (arteritic, non-arteritic) Orbital compressive lesions. The disinhibited patient may be inap propriately jocular (witzelsucht), short-tempered (verbally abusive, physically aggressive), distractible (impaired attentional mechanisms), and show emo tional lability. A Disinhibition Scale encompassing various domains (motor, intellectual, instinctive, affective, sensitive) has been described. Disinhibition is a feature of frontal lobe, particularly orbitofrontal, dysfunc tion. This may be due to neurodegenerative disorders (frontotemporal dementia, Alzheimer’s disease), mass lesions, or be a feature of epileptic seizures. Cross References Attention; Emotionalism, Emotional lability; Frontal lobe syndromes; Witzelsucht Dissociated Sensory Loss Dissociated sensory loss refers to impairment of selected sensory modalities with preservation, or sparing, of others. For example, a focal central cord pathology such as syringomyelia will, in the early stages, selectively involve decussating bres of the spinothalamic pathway within the ventral commissure, thus impair ing pain and temperature sensation (often in a suspended, ‘cape-like’, ‘bathing suit’, ‘vest-like’, or cuirasse distribution), whilst the dorsal columns are spared, leaving proprioception intact. Conversely, pathologies con ned, largely or exclusively, to the dorsal columns (classically tabes dorsalis and subacute combined degenera tion of the cord from vitamin B12 de ciency, but probably most commonly seen with compressive cervical myelopathy) impair proprioception, sometimes suf cient to produce pseudoathetosis or sensory ataxia, whilst pain and temperature sensation is preserved. A double dissociation of sensory modalities on opposite sides of the trunk is seen in the Brown–Sequard syndrome. Small bre peripheral neuropathies may selectively affect the bres which transmit pain and temperature sensation, leading to a glove-and-stocking impair ment to these modalities. Neuropathic (Charcot) joints and skin ulceration may occur in this situation; tendon re exes may be preserved. Cross References Analgesia; Ataxia; Brown–Sequard syndrome; Charcot joint; Main succulente; Myelopathy; Proprioception; Pseudoathetosis; Sacral sparing Dissociation Dissociation is an umbrella term for a wide range of symptoms involving feelings of disconnection from the body (depersonalization) or the surroundings (dere alization). Common in psychiatric disorders (depression, anxiety, schizophre nia), these symptoms are also encountered in neurological conditions (epilepsy, migraine, presyncope), conditions such as functional weakness and non-epilpetic attacks, and in isolation by a signi cant proportion of the general population. Symptoms of dizziness and blankness may well be the result of dissociative states rather than neurological disease. The superior division or ramus supplies the superior rectus and levator palpebrae superioris muscles; the inferior division or ramus supplies medial rectus, inferior rectus and inferior oblique muscles. Isolated dys function of these muscular groups allows diagnosis of a divisional palsy and suggests pathology at the superior orbital ssure or anterior cavernous sinus. However, occasionally this division may occur more proximally, at the fascicu lar level. Proximal superior division oculomotor nerve palsy from metastatic subarachnoid in ltration Journal of Neurology 2002; 249: 343–344. Although this can be done in a conscious patient focusing on a visual target, smooth pursuit eye movements may compensate for head turn ing; hence the head impulse test (q. The manoeuvre is easier to do in the unconscious patient, when testing for the integrity of brainstem re exes. Cross References Bell’s phenomenon, Bell’s sign; Caloric testing; Coma; Head impulse test; Oculocephalic response; Supranuclear gaze palsy; Vestibulo-ocular re exes 112 Dropped Head Syndrome D Dorsal Guttering Dorsal guttering refers to the marked prominence of the extensor tendons on the dorsal surface of the hand when intrinsic hand muscles (especially interossei) are wasted, as may occur in an ulnar nerve lesion, a lower brachial plexus lesion, or a T1 root lesion. Benign extramedullary tumours at the foramen magnum may also produce this picture (remote atrophy, a ‘false-localizing sign’). In many elderly people the extensor tendons are prominent in the absence of signi cant muscle wasting. Cross Reference Wasting Double Elevator Palsy this name has been given to monocular elevation paresis. It may occur in associ ation with pretectal supranuclear lesions either contralateral or ipsilateral to the paretic eye interrupting efferents from the rostral interstitial nucleus of the medial longitudinal fasciculus to the superior rectus and inferior oblique subnuclei. This syndrome has a broad differ ential diagnosis, encompassing disorders which may cause axial truncal muscle weakness, especially of upper thoracic and paraspinous muscles. Treatment of the underlying condition may be possible, hence investigation is mandatory. Cross References Antecollis; Camptocormia; Myopathy Drusen Drusen are hyaline bodies that are typically seen on and around the optic nerve head and may be mistaken for papilloedema (‘pseudopapilloedema’). They occur sporadically or may be inherited in an autosomal dominant fashion, and are common, occurring in 2% of the population. Drusen are usually asymptomatic but can cause visual eld defects (typically an inferior nasal visual eld loss) or occasionally transient visual obscurations, but not changes in visual acuity; these require investigation for an alternative cause. When there is doubt whether papilloedema or drusen is the cause of a swollen optic nerve head, retinal uorescein angiography is required. Cross References Disc swelling; Papilloedema; Pseudopapilloedema; Visual eld defects 114 Dysarthria D Dynamic Aphasia Dynamic aphasia refers to an aphasia characterized by dif culty initiating speech output, ascribed to executive dysfunction. There is a reduction in spontaneous speech, but on formal testing there are no paraphasias, minimal anomia, pre served repetition, and automatic speech. Dynamic aphasia may be conceptualized as a variant of transcortical motor aphasia and may be seen with lesions of dorsolateral prefrontal cortex (‘frontal aphasia’). A division into pure and mixed forms has been suggested, with additional phonological, lexical, syntactical, and articulatory impairments in the latter. Cross References Echolalia; Transcortical aphasias Dysaesthesia Dysaesthesia is an unpleasant, abnormal or unfamiliar, sensation, often with a burning and/or ‘electrical’ quality. Some authorities reserve the term for provoked positive sensory phenomena, as opposed to spontaneous sensations (paraesthesia). Dysaesthesia differs from paraesthesia in its unpleasant quality, but may overlap in some respects with allodynia, hyperalgesia, and hyper pathia (the latter phenomena are provoked by stimuli, either non-noxious or noxious).

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In particular order advair diskus 100mcg with amex asthma symptoms pain in back, many struct comprehensive variation maps of the cancers involve the epigenetic inactivation of human genome (1a) generic 500 mcg advair diskus with amex asthma differential diagnosis. These data indicate that plex interactions of multiple genes and vari transcriptional regulatory elements generic advair diskus 250mcg without prescription asthma definition 9 amendment, particu ants residing therein that may affect advair diskus 250mcg for sale asthmatic bronchitis otc treatment, for ex larly promoters, may represent a major site ample, disease susceptibility or progression. Clearly, annotating all functional tran that underlie such diseases is categorizing scriptional regulatory elements in the human the single-base differences among individuals, genome will be valuable for future medical known as single-nucleotide polymorphisms studies. In assays that Activity measure enhancer-blocking activity, the ge One of the more versatile methods for iden nomicsegmentcontainingaputativeinsulator tifying and analyzing transcriptional regu is positioned between an enhancer and a pro latory element activity is based on the use moter that are known to interact; if present, of a reporter-gene assay. Although tradition an insulator should interfere with enhancer ally used for directed studies, this method promoter communication when positioned holds the promise of being adapted for use between the two elements. For the purposes of position effects, particularly from the repres large-scale screens, the genomic segments can sive effects of heterochromatin, allowing for be generated randomly either by enzymatic position-independent reporter gene expres or physical means. The precise con guration of There are several challenges in using func the reporter construct depends on the regula tional assays to identify transcriptional reg tory element to be identi ed. First, regulatory elements the genomic segment is being tested for core can be widely dispersed, and it can be dif promoter activity, then it is placed immedi cult to capture them all in a single reporter ately upstream of a reporter gene lacking an construct. Proximal ing only a portion of a promoter element will promoters can be assayed in a similar manner, likelynotrecapitulatetheexpressionofitscor if they are cloned upstream of a reporter gene responding gene. Second, the in vivo activity driven by a weak heterologous core promoter of a reporter gene may fail to duplicate the that allows increases in transcription to be de expression pattern of its endogenous counter tected (Figure 5b). If the cell culture system used to assay linker-scanning mutagenesis, or site-directed the reporter gene activity does not match the mutagenesis can be employed to more accu physiological conditions under which the reg rately delineate the functional element(s). Genomic segment Reporter construct Figure 5 Functional assays that measure transcriptional regulatory element activity. Traditional methods for analyzing the activity of a transcriptional regulatory element are based on the use of plasmid-based or transgenic-reporter gene assays. Depending on the protein factor allows the following reporter gene expression through that serves as the immunoprecipitation tar determination of the the entire development of the organism (54, get, the technique can detect enhancers (24, entire spectrum of in vivo binding sites for 139). Despite these limi methodologies, however, have certain limi tations, however, reporter gene assays remain tations. Recently, a tech genomic methods must be cautiously inter nique was developed for high-throughput preted. Such an approach is pow site in the genome, they do not demonstrate erful in its capacity to detect any regulatory that each and every site is a functional element element associated with chromotin perturba that regulates transcription of a target gene. In 44 Maston · Evans · Green fact, recent studies suggest that this is highly unlikely. Similar results have been obtained tate the entire human genome for all functional elements. In addition, because promoters Toward this end, efforts are under way to can contain any one of a number of combi adapt existing methods for high-throughput nations of core promoter elements [and, con applications, and to develop new methodolo versely, many promoters have only one or no gies. This analysis is often provide ample data from which to discover hampered by the prediction of a large num novel promoter structures and construct bet ber of sites, a signi cant fraction of which are ter models of core promoters. Unfortunately, alternative analysis technique used to over for the other half of genes not associated with come the above-mentioned challenges is to CpG islands, whose tissue-speci c regulation amass genes that are suspected to be coregu is arguably more interesting and complex, ab lated (or experimentally determined to be co initio promoter predictions are much less re expressed, such as from a microarray analy liable. Ex uate and compare the performance of such perimental data regarding the speci c bind programs (181). It is clear that there is room ing sites of most well-characterized transcrip for improvement, especially when analyzing 46 Maston · Evans · Green metazoan sequences, in which transcription relation between conservation and function factor cooperativity is much more widespread results, in part, from the presence of a large thaninyeastandlowereukaryotes. Infact,fur amount of highly conserved noncoding se Phylogenetic ther improvement in the success of predicting quences in the human genome. An types of transcriptional regulatory elements conserved sequences other strategy that has become widely ex or clusters of elements (41, 165). In one form regulation, or if they perhaps serve an as-yet Phylogenetic of this, known as phylogenetic footprinting de ned other role. For example, it sequence analyses pared, and those sequences found to be in has been estimated that roughly one third of that compares closely common. This could be due to a num rather than distantly related sequences approach is based on the expectation that ber of reasons. Second, al have been developed to perform such anal though gene-expression patterns may be con yses, such as FootPrinter (21) and PhastCons served across species, a speci c regulatory el (165). As with the other prediction tools dis ement may not be conserved (61, 118, 188); cussed above, a recent analysis of the accu this can occur because of redundancy of reg racy of some of these programs suggests that ulatory elements (76, 159) that allows a single they are acceptable, but imperfect, in cor element to be gained or lost without affecting rectly identifying known functional sites (90). Two thorough reviews have covered the grow Finally, some of the most important tran ing eld of comparative genomics (129) and scriptional regulatory elements relevant to the challenges faced in the statistical imple normal human development and disease may mentation of comparative sequence analyses not be highly conserved, but rather might (171). The comments below are thus lim be found only in humans or shared with a ited to a broader perspective on the use of small group of our primate relatives. First, al methods will likely depend on advances in though there is ample evidence that conserved comparative genomics; this may require new regions do, indeed, often contain functional analytical approaches, such as phylogenetic regulatory motifs (121, 139, 193), this corre shadowing (22) that analyzes closely related lation does not always hold (10), and other sequences. In often located distantly from the promoter terplay between the entire suite of core pro upon which they act, and are not always moters, proximal regulatory elements, and conserved through evolution. These prop distal regulatory elements, as well as their erties make regulatory elements dif cult to binding factors and cofactors, contribute to identify through computational means alone. Regulatory systems of a transcription factor at a given site, but are robust and redundant, and yet highly sen do not assess the functional signi cance of sitive as well: Even single-nucleotide differ that binding. Functional assays that directly ences in a regulatory sequence can have sig assess the regulatory capacity of a site are ni cant effects on gene expression. These re the best available tools, and the current chal sults suggest that transcriptional regulation lenge is to adapt these methods for their high can cover a broad, continuous spectrum of throughput usage to screen the entire human regulatory control, such that it is likely that genome. The concerted action of multiple different transcriptional regulatory elements, along with their cognate activators and coactivators, contributes to the overall spatial and temporal regulation of a gene’s expression pattern.

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This process may be asymptomatic in its early stages order advair diskus 250 mcg mastercard asthma with status asthmaticus, but may later be a cause of nyctalopia (night blindness) discount 100mcg advair diskus with amex asthmatic bronchitis quizlet, and produce a midperipheral ring scotoma on visual eld testing advair diskus 250 mcg sale asthmatic bronchitis 32. A variety of genetic causes of isolated retinitis pigmentosa have been partially characterized: • autosomal recessive: linked to cheap 100mcg advair diskus otc asthma prophylaxis definition chromosome 1q; • X-linked: Xp11, Xp21; • autosomal dominant:3q,6p,8. Looking at protein misfolding neurodegenerative disease through retinitis pigmentosa. Cross References Nyctalopia; Optic atrophy; Scotoma Retinopathy Retinopathy is a pathological process affecting the retina, with changes observ able on ophthalmoscopy; dilatation of the pupil aids observation of the periph eral retina. Laser treatment of new vessels is the treatment of choice • Hypertension: hypertensive retinopathy may cause arteriolar constriction, with the development of cotton–wool spots; and abnormal vascular per meability causing ame-shaped haemorrhages, retinal oedema, and hard exudates; around the fovea, the latter may produce a macular star. Systemic hypertension is associated with an increased risk of branch retinal vein and central retinal artery occlusion • Drug-induced. Cross References Maculopathy; Retinitis pigmentosa; Scotoma Retrocollis Retrocollis is an extended posture of the neck. Retrocollis may also be a feature of cervical dystonia (torticollis) and of kernicterus. This phenomenon does not have partic ular localizing value, since it may occur with both occipital and anterior visual pathway lesions. Cross References Akinetopsia; Visual agnosia Right–Left Disorientation Right–left disorientation is an inability to say whether a part of the body is on the right or left side or to use a named body part to command. This may occur in association with acalculia, agraphia, and nger agnosia, collectively known as the Gerstmann syndrome. Although all these features are dissociable, their concurrence indicates a posterior parietal dominant hemisphere lesion involving the angular and supramarginal gyri. Cross References Acalculia; Agraphia; Autotopagnosia; Finger agnosia; Gerstmann syndrome Rigidity Rigidity is an increased resistance to the passive movement of a joint which is constant throughout the range of joint displacement and not related to the speed of joint movement; resistance is present in both agonist and antagonist mus cles. Rigidity may be described as: • consistent: ‘leadpipe rigidity’; or • jerky: ‘cogwheel rigidity’ or Negro’s sign, when a rhythmic uctuation. However, this may occur in some normal subjects; it is most helpful in the diagnosis of Parkinson’s disease if unilateral. Rigidity is a feature of parkinsonism and may coexist with any of the other clinical features of extrapyramidal system disease, but particularly akinesia (akinetic-rigid syndrome); both are associated with loss of dopamine projections from the substantia nigra to the putamen. The pathophysiology of rigidity is thought to relate to overactivity of tonic stretch re exes in the spinal cord due to excessive supraspinal drive to spinal cord 313 R Rindblindheit motor neurones following loss of descending inhibition as a result of basal gan glia dysfunction. In other words, there is a change in the sensitivity of the spinal interneurones which control motor neurones due to defective supraspinal con trol. Hence rigidity is a positive or release symptom, re ecting the operation of intact suprasegmental centres. In support of this, pyramidotomy has in the past been shown to produce some relief of rigidity. Rigidity in Parkinson’s disease may be lessened by treatment with levodopa preparations. The techniques of modern stereotactic neurosurgery may also be helpful, particularly stimulation of the subthalamic nucleus, although both thalamotomy and pallidotomy may also have an effect. The term rigidity may also be used to describe • posturing associated with coma: decorticate or decerebrate, exor and extensor posturing, respectively; • a lack of mental exibility, particularly evident in patients with frontal lobe dysfunction. Pathophysiology of Parkinson’s disease rigidity: role of corticospinal motor projections. Neurophysiology of Parkinson’s disease, levodopa-induced dyskinesias, dystonia, Huntington’s disease and myoclonus. Relationship between electromyographic activity and clin ically assessed rigidity studied at the wrist joint in Parkinson’s disease. Risus sardonicus may also occur in the context of dystonia, more usually symptomatic (secondary) than idiopathic (primary) dystonia. Cross References Parkinsonism; ‘Wheelchair sign’ Roger’s Sign Roger’s sign, or the numb chin syndrome, is an isolated neuropathy affecting the mental branch of the mandibular division of the trigeminal (V) nerve, causing pain, swelling, and numbness of the lower lip, chin, and mucous membrane inside the lip. Hypoaesthesia involving the cheek, upper lip, upper incisors, and gingiva, due to involvement of the infraorbital portion of the maxillary division of the trigeminal nerve (‘numb cheek syndrome’), is also often an ominous sign, result ing from recurrence of squamous cell carcinoma of the face in ltrating the nerve. Le signe du mentonnier (parasthesie et anesthesie unilaterale) revelateur d’un processus neoplasique metastatique. Cross References Parkinsonism; Wartenberg’s swing test Rombergism, Romberg’s Sign Romberg’s sign is adjudged present (or positive) when there is a dramatic increase in unsteadiness, sometimes with falls, after eye closure in a patient standing com fortably (static Romberg’s test). Before asking the patient to close his or her eyes, it is advisable to position ones arms in such a way as to be able to catch the patient should they begin to fall. A modest increase in sway on closing the eyes may be seen in normal subjects and patients with cerebellar ataxia, frontal lobe ataxia, and vestibular disorders (towards the side of the involved ear); on occasion these too may produce an increase in sway suf cient to cause falls. Large amplitude sway without falling, due to the patient clutching hold of the physician, has been labelled ‘psychogenic Romberg’s sign’, an indicator of functional stance impairment. Heel–toe (tandem) walking along a straight line is sometimes known as the dynamic Romberg’s test. Cross References Ataxia; Functional weakness and sensory disturbance; Proprioception; Tandem walking Roos Test Roos test, or the elevated arm stress test, may be helpful in the diagnosis of vascu lar thoracic outlet syndrome, along with Adson’s test. Development of numbness, pain, and paraesthesia, along with pallor of the hand, supports the diagnosis of thoracic outlet syndrome. Its presence in adults is indicative of diffuse premotor frontal disease, this being a primitive re ex or frontal release sign. These movements may be performed voluntar ily (tested clinically by asking the patient to ‘Look to your left, keeping your head still’, etc. A number of parameters may be observed, including latency of saccade onset, saccadic amplitude, and saccadic velocity. Of these, saccadic velocity is the most important in terms of localization value, since it depends on burst neurones in the brainstem (para median pontine reticular formation for horizontal saccades, rostral interstitial nucleus of the medial longitudinal fasciculus for vertical saccades). Latency involves cortical and basal ganglia circuits; antisaccades involve frontal lobe structures; and amplitude involves basal ganglia and cerebellar circuits (saccadic hypometria, with a subsequent correctional saccade, may be seen in extrapyra midal disorders such as Parkinson’s disease; saccadic hypermetria or overshoot may be seen in cerebellar disorders).