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malformations. They found that patients with AWMtended to present with a large bleed, causing headache andsubarachnoid haemorrhage. Those with AOVM were morelikely to have an evolving or episodic disturbance, leading toan incorrect diagnosis of multiple sclerosis in some patients.We are not told whether there was any supportive evidencefor the clinical diagnosis of demyelination; such

misdiagnosis has been reported by others.5 Nor is it clearhow often MRI was the only investigation that revealed anabnormality but probably it was seldom. Usually the CTscan showed a hyperdense lesion and the differential

diagnosis for this is between haemorrhage, calcification,astrocytoma, oligodendroglioma, and granuloma. Less

commonly an area of reduced density was seen. MRI candistinguish between haemorrhage and the others.One reason for distinguishing AOVM from non-vascular

lesions is that surgery may have something to offer topatients with vascular malformation. In those with

brainstem malformations surgery is often not feasible, butvarious radiotherapeutic measures, including stereotacticprocedures, are now being evaluated.Vascular malformations are classified neuro-

pathologically as capillary telangiectases, cavernous

angiomas, and (arterio-)venous malformations. Capillarytelangiectases are a cluster of dilated capillary channels andare a common incidental finding at necropsy; they are mostfrequently over the pons and the cerebral cortex. Cavernousangiomas are thin-walled blood-filled spaces and are usuallylarger than capillary telangiectases. Arteriovenousmalformations consist of a tangle of vessels, usually arteriesand veins in which the former have excess elastic tissue andthe latter walls thickened by collagen. Abe et al did not haveenough histological data to classify their malformations, butit is possible that the capillary telangiectases and cavernousangiomas, which are low pressure and low flow systems,do not present with large haemorrhages and are

angiographically occult.

WHICH ORTHOSIS?

CONSIDERABLE media attention has lately been focusedon the problems of getting young paraplegic patients towalk. The high technology approach-ie, use of electricalimpulses to stimulate coordinated muscle function andthereby permit ambulation-has been emphasised. Thesetechniques are still experimental and are available only inspecialist centres. However, the difficulties faced by youngparaplegics are very real; any help that can be given to thisgroup of people to allow them to walk will not only facilitatean independent existence and improve their self-esteem butalso may well decrease the costs to the community in lookingafter them.Two orthoses have lately been developed to help young

paraplegic people to walk. The hip guidance orthosis

(HGO) is British and designed along classical NationalHealth Service lines, with substantial leather and metalcomponents and a regard for utility rather than cosmesis.The reciprocating gait orthosis (RGO) is American andmakes use of lightweight plastics. Unlike the HGO, theRGO is designed to be worn under clothing and is thereforecosmetically more acceptable.

5. Britt RH, Connor WS, Enzmann DR. Occult arteriovenous malformation of the brainstem simulating multiple sclerosis. Neurology 1981; 31: 901-04.

A comprehensive prospective trial was carried out toevaluate these two orthoses by the then Department ofHealth and Social Security.1 Unfortunately, few childrencould be recruited, so the study was undertaken withtwenty-two adults. Variables assessed included ease of

measurement; fabrication and fitting of the orthoses;training that was required to achieve competence in theiruse; clinical, ergonomic, and biochemical differences;psychological aspects associated with their use; relative cost;and acceptability to the patients.

In many ways the two orthoses were very similar. Most

patients were fitted fairly easily, although considerableattention to detail was required to achieve a satisfactoryresult. The RGO failed in two patients whereas nostructural failure was recorded with the more substantialHGO. The RGO took twice as long to manufacture and cost£ 1772 vs C 1116 for the HGO. Results of ergonomic testingwere evenly split, the HGO being quicker to doff and donand the RGO allowing for more rapid standing. Thedifferences in the times to doff and don the orthoses are

mainly related to the fact that the HGO is worn over theclothes and the RGO under them. Videotape and gaitanalysis showed no significant difference in walking qualityand only minor differences in gait. Energy consumption wassimilar for both appliances.Comparison between the two orthoses ultimately comes

down to consumer preference, with twelve patients optingfor the RGO and four for the HGO. The remaining sixpatients were either unable or did not wish to use an orthosisafter the trial. Cosmesis undoubtedly played a major part inthe choice of orthosis; it is interesting that psychologicalanalysis showed that highly anxious people might not besuitable for the HGO.

AUTONOMIC NEUROPATHY IN LIVERDISEASE

AUTONOMIC nervous dysfunction is an important causeof morbidity and mortality in diabetes mellitus2 andalcoholism.3 Its presence in other diseases of metabolism hasnot been fully assessed. The autonomic neuropathy ofdiabetes is characterised by an unremitting course.

Widespread subclinical nerve damage can precede themanifestations of disordered carbohydrate metabolism;4 4both parasympathetic and sympathetic nerves are involved,with the brunt of the damage being borne by the vagus nerveand splanchnic sympathetics. Complications such as

orthostatic hypotension can be ameliorated but continue topfogress. The 5-year mortality rate in diabetic patients oncea symptomatic neuropathy has developed is 56 %P Inchronic alcoholics the 7-year mortality is between 20 and34%; the lower figure is nonetheless 10-20% above that fornon-alcoholic controls. Autonomic neuropathy fromalcohol abuse differs from diabetic neuropathy in that fewerpatients have sympathetic dysfunction. Moreover, withcontinued abstinence, chronic alcoholics with vagal

1. A comparative evaluation of the hip guidance orthosis (HGO) and the reciprocatinggait orthosis (RGO). Health Equipment Information 192. DH, NHS ProcurementDirectorate, 14 Russell Square, London WC1B 5EP.

2. Ewing DJ, Campbell IW, Clarke BF. The natural history of diabetic autonomicneuropathy. Quart J Med 1980; 49: 95-105.

3. Johnson RH, Robinson BJ Mortality in alcoholics with autonomic neuropathy.J Neurol Neurosurg Psychiatry 1988; 51: 476-80.

4. Rundles RW Diabetic neuropathy. Medicine 1945, 24: 110-60