Pure autonomic failure with cold induced sweating

Pure autonomic failure (PAF) is a progressive autonomic neurodegenerative disorder. Cold induced sweating occurred in syndromes with mutations in CRLF1 and CLCF1 genes and in a case of cervical dissection. A patient with PAF developed sweating induced by cool ambient temperatures. He had severe orthostatic hypotension, abnormal cardiovagal reflexes, and paradoxical sweating in the upper trunk at a room temperature of 18°C. Skin biopsy showed involvement of somatic epidermal unmyelinated nerve fibers. Quantitative sensory testing showed abnormal thresholds to all thermal modalities. Possible mechanisms include cold induced noradrenaline release in remaining autonomic innervation and a supersensitive sudomotor response.

Headache in three new cases of Harlequin syndrome with accompanying pharmacological comparison with migraine

BACKGROUND

Harlequin syndrome (HS) is a rare autonomic disorder characterised by unilateral diminished sweating and flushing of the face in response to heat or exercise. Some patients with HS complain of headache.

METHODS

We present three new cases to characterise their headache phenotype and pharmacology and review the literature of cases where headache was described. RESULTS Two out of the three patients presented with episodes of unilateral headache associated with exercise: in one case the headache had migrainous features and was contralateral to the side where the flushing occurred, whereas the second patient, who had had migraine attacks in the past, had a brief throbbing headache, with no associated symptoms, ipsilateral to the facial flushing. The third woman had migraine but the attacks were not associated with HS. Pharmacological characterisation suggested the HS and migraine were biologically distinct. HS was not triggered by nitroglycerin and was unaffected by sumatriptan, dihydroergotamine and ergotamine. HS and migraine did not occur together. In the literature, we found six patients with both HS and headache, five of whom had migraine.

CONCLUSIONS

These data do not show any correlation between the phenotypic expression of migraine and HS suggesting the syndromes are pathogenetically independent.

Progression of cardiovascular autonomic dysfunction in Holmes-Adie syndrome

The Holmes-Adie Syndrome (HAS) is a disorder of unknown aetiology comprising unilateral or bilateral tonic pupils with near light dissociation and tendon areflexia. Although considered to be benign, troublesome symptoms may result from autonomic disturbances, affecting vasomotor, sudomotor and respiratory function. It is unclear if the autonomic manifestations of the disease remain stable or progress, as longitudinal studies with detailed autonomic assessments have not been described. The authors report four HAS patients studied at intervals over 16, 8, 4 and 2 years with cardiovascular autonomic tests (head-up tilt, isometric exercise, mental arithmetic, cutaneous cold, deep breathing, Valsalva manoeuvre and standing). In each, there was progression of cardiovascular autonomic deficits with time, accompanied by symptomatic worsening. These observations in HAS, for the first time, indicate progression of cardiovascular autonomic dysfunction of clinical significance. This has a number of implications, including those relating to aetiology and prognosis. The authors recommend regular clinical and laboratory follow-up, especially of cardiovascular autonomic function, in patients with HAS.

Action of 5 Hz repetitive transcranial magnetic stimulation on sensory, motor and autonomic function in human spinal cord injury

OBJECTIVE

To assess the effectiveness of physiological outcome measures in detecting functional change in the degree of impairment of spinal cord injury (SCI) following repetitive transcranial magnetic stimulation (rTMS) of the sensorimotor cortex.

METHODS

Subjects with complete or incomplete cervical (or T1) SCI received real and sham rTMS in a randomised placebo-controlled single-blinded cross-over trial. rTMS at sub-threshold intensity for upper-limb muscles was applied (5 Hz, 900 stimuli) on 5 consecutive days. Assessments made before and for 2 weeks after treatment comprised the ASIA (American Spinal Injuries Association) impairment scale (AIS), the Action Research Arm Test (ARAT), a peg-board test, electrical perceptual test (EPT), motor evoked potentials, cortical silent period, cardiovascular and sympathetic skin responses.

RESULTS

There were no significant differences in AIS outcomes between real and sham rTMS. The ARAT was increased at 1h after real rTMS compared to baseline. Active motor threshold for the most caudally innervated hand muscle was increased at 72 and 120 h compared to baseline. Persistent reductions in EPT to rTMS occurred in two individuals.

CONCLUSIONS

Changes in cortical motor threshold measures may accompany functional gains to rTMS in SCI subjects.

SIGNIFICANCE

Electrophysiological measures may provide a useful adjunct to ASIA impairment scales.

Presentation, diagnosis, and management of multiple system atrophy in Europe: final analysis of the European multiple system atrophy registry

Multiple system atrophy (MSA) is a Parkinson's Disease (PD)-like α-synucleinopathy clinically characterized by dysautonomia, parkinsonism, cerebellar ataxia, and pyramidal signs in any combination. We aimed to determine whether the clinical presentation of MSA as well as diagnostic and therapeutic strategies differ across Europe and Israel. In 19 European MSA Study Group centres all consecutive patients with a clinical diagnosis of MSA were recruited from 2001 to 2005. A standardized minimal data set was obtained from all patients. Four-hundred thirty-seven MSA patients from 19 centres in 10 countries were included. Mean age at onset was 57.8 years; mean disease duration at inclusion was 5.8 years. According to the consensus criteria 68% were classified as parkinsonian type (MSA-P) and 32% as cerebellar type (MSA-C) (probable MSA: 72%, possible MSA: 28%). Symptomatic dysautonomia was present in almost all patients, and urinary dysfunction (83%) more common than symptomatic orthostatic hypotension (75%). Cerebellar ataxia was present in 64%, and parkinsonism in 87%, of all cases. No significant differences in the clinical presentation were observed between the participating countries. In contrast, diagnostic work up and therapeutic strategies were heterogeneous. Less than a third of patients with documented orthostatic hypotension or neurogenic bladder disturbance were receiving treatment. This largest clinical series of MSA patients reported so far shows that the disease presents uniformly across Europe. The observed differences in diagnostic and therapeutic management including lack of therapy for dysautonomia emphasize the need for future guidelines in these areas.

The isolated sympathetic spinal cord: Cardiovascular and sudomotor assessment in spinal cord injury patients: A literature survey

OBJECTIVES

To present a comprehensive approach to the assessment of the severity of the autonomic lesion in spinal cord injury (SCI) patients, with regard to the level of lesion. To discuss how to assess an isolated sympathetic spinal cord that has lost supraspinal control (sympathetically complete lesion).

METHOD

PubMed was searched for articles related to cardiovascular (mainly cold pressor test, respiratory and postural challenges) and sudomotor (sympathetic skin responses) tests that have been used. The results of these evaluations are analysed with regard to the site of stimulation (above or below the lesion) according to three types of SCI that offer typical autonomic reactions (tetraplegics, paraplegics at T6 and at T10).

RESULTS

Non-invasive cardiovascular and sudomotor testing allows the assessment of the isolated sympathetic spinal cord in SCI patients. Typical responses are found in relation with the level of the sympathetic lesion. Its definition would allow comparison with the somatic motor and sensory level of lesion of SCI patients and provide additional aid to the classification of those patients.

CONCLUSION

For research purposes on the integrity of the spinal sympathetic pathways, a battery of test approach is probably needed, using a combination of stimuli above and below the lesion, evaluating both cardiovascular and sudomotor pathways.

International spinal cord injury cardiovascular function basic data set

OBJECTIVE

To create an International Spinal Cord Injury (SCI) Cardiovascular Function Basic Data Set within the framework of the International SCI Data Sets.

SETTING

An international working group.

METHODS

The draft of the data set was developed by a working group comprising members appointed by the American Spinal Injury Association (ASIA), the International Spinal Cord Society (ISCoS) and a representative of the executive committee of the International SCI Standards and Data Sets. The final version of the data set was developed after review by members of the executive committee of the International SCI Standards and Data Sets, the ISCoS scientific committee, ASIA board, relevant and interested international organizations and societies, individual persons with specific interest and the ISCoS Council. To make the data set uniform, each variable and each response category within each variable have been specifically defined in a way that is designed to promote the collection and reporting of comparable minimal data.

RESULTS

The variables included in the International SCI Cardiovascular Function Basic Data Set include the following items: date of data collection, cardiovascular history before the spinal cord lesion, events related to cardiovascular function after the spinal cord lesion, cardiovascular function after the spinal cord lesion, medications affecting cardiovascular function on the day of examination; and objective measures of cardiovascular functions, including time of examination, position of examination, pulse and blood pressure. The complete instructions for data collection and the data sheet itself are freely available on the websites of both ISCoS (http://www.iscos.org.uk) and ASIA (http://www.asia-spinalinjury.org).

Effects of water drinking on cardiovascular responses to supine exercise and on orthostatic hypotension after exercise in pure autonomic failure

OBJECTIVE

Patients with pure autonomic failure (PAF) have an abnormal fall in blood pressure (BP) with supine exercise and exacerbation of orthostatic hypotension (OH) after exercise. This study assessed the pressor effect of water on the cardiovascular responses to supine exercise and on OH after exercise.

METHODS

8 patients with PAF underwent a test protocol consisting of standing for 5 min, supine rest for 10 min, supine exercise by pedalling a cycle ergometer at workloads of 25, 50 and 75 W (each for 3 min), supine rest for 10 min and standing for 5 min. The test protocol was performed without water ingestion and on a separate occasion after 480 ml of distilled water immediately after pre-exercise standing. Beat to beat cardiovascular indices were measured with the Portapres II device with subsequent Modelflow analysis.

RESULTS

All patients had severe OH pre-exercise (BP fall systolic 65.0 (26.1) mm Hg, diastolic 22.7 (13.5) mm Hg), with prompt recovery of BP in the supine position. 5 min after water drinking, there was a significant rise in BP in the supine position. With exercise, there was a clear fall in BP (systolic 42.1 (24.4) mm Hg, diastolic 25.9 (10.0) mm Hg) with a modest rise in heart rate; this occurred even after water ingestion (BP fall systolic 49.8 (18.9) mm Hg, diastolic 26.0 (9.1) mm Hg). BP remained low after exercise but was significantly higher after water intake, resulting in better tolerance of post-exercise standing.

CONCLUSIONS

Water drinking did not change the abnormal cardiovascular responses to supine exercise. However, water drinking improved orthostatic tolerance post-exercise.

Second consensus statement on the diagnosis of multiple system atrophy

BACKGROUND

A consensus conference on multiple system atrophy (MSA) in 1998 established criteria for diagnosis that have been accepted widely. Since then, clinical, laboratory, neuropathologic, and imaging studies have advanced the field, requiring a fresh evaluation of diagnostic criteria. We held a second consensus conference in 2007 and present the results here.

METHODS

Experts in the clinical, neuropathologic, and imaging aspects of MSA were invited to participate in a 2-day consensus conference. Participants were divided into five groups, consisting of specialists in the parkinsonian, cerebellar, autonomic, neuropathologic, and imaging aspects of the disorder. Each group independently wrote diagnostic criteria for its area of expertise in advance of the meeting. These criteria were discussed and reconciled during the meeting using consensus methodology.

RESULTS

The new criteria retain the diagnostic categories of MSA with predominant parkinsonism and MSA with predominant cerebellar ataxia to designate the predominant motor features and also retain the designations of definite, probable, and possible MSA. Definite MSA requires neuropathologic demonstration of CNS alpha-synuclein-positive glial cytoplasmic inclusions with neurodegenerative changes in striatonigral or olivopontocerebellar structures. Probable MSA requires a sporadic, progressive adult-onset disorder including rigorously defined autonomic failure and poorly levodopa-responsive parkinsonism or cerebellar ataxia. Possible MSA requires a sporadic, progressive adult-onset disease including parkinsonism or cerebellar ataxia and at least one feature suggesting autonomic dysfunction plus one other feature that may be a clinical or a neuroimaging abnormality.

CONCLUSIONS

These new criteria have simplified the previous criteria, have incorporated current knowledge, and are expected to enhance future assessments of the disease.

Progression of dysautonomia in multiple system atrophy: a prospective study of self-perceived impairment

To assess severity and progression of self-perceived dysautonomia and their impact on health-related quality of life (Hr-QoL) in multiple system atrophy (MSA), twenty-seven patients were recruited by the European MSA Study Group (EMSA-SG). At baseline, all patients completed the Composite Autonomic Symptom Scale (COMPASS) and the 36 item Short Form Health Survey (SF-36), and they were assessed using the 3-point global disease severity scale (SS-3) and the Unified MSA Rating Scale (UMSARS). After 6 months follow-up, the self completed COMPASS Change Scale (CCS), the SF-36, SS-3, and UMSARS were obtained. MSA patients showed marked self-perceived dysautonomia at baseline visit and pronounced worsening of dysautonomia severity on the CCS at follow-up. Severity and progression of dysautonomia did not correlate with age, disease duration, motor impairment and overall disease severity at baseline. There were no significant differences between genders and motor subtypes. Baseline COMPASS scores were, however, inversely correlated with SF-36 scores. Progression of self-perceived dysautonomia did not correlate with global disease progression. Hr-QoL scores were stable during follow-up. This is the first study to investigate self-perceived dysautonomia severity in MSA and its evolution over time. Our data suggest that dysautonomia should be recognized as a key target for therapeutic intervention in MSA.

Unexplained syncope--is screening for carotid sinus hypersensitivity indicated in all patients aged >40 years?

OBJECTIVE

To determine the frequency, age distribution and clinical presentation of carotid sinus hypersensitivity (CSH) among 373 patients (age range 15-92 years) referred to two autonomic referral centres during a 10-year period.

METHODS

Carotid sinus massage (CSM) was performed both supine and during 60 degree head-up tilt. Beat-to-beat blood pressure, heart rate and a three-lead electrocardiography were recorded continuously. CSH was classified as cardioinhibitory (asystole > or = 3 s), vasodepressor (systolic blood pressure fall > or = 50 mm Hg) or mixed. All patients additionally underwent autonomic screening tests for orthostatic hypotension and autonomic failure.

RESULTS

CSH was observed in 13.7% of all patients. The diagnostic yield of CSM was nil in patients aged < 50 years (n = 65), 2.4% in those aged 50-59 years (n = 82), 9.1% in those aged 60-69 years (n = 77), 20.7% in those aged 70-79 years (n = 92) and reached 40.4% in those > 80 years (n = 57). Syncope was the leading clinical symptom in 62.8%. In 27.4% of patients falls without definite loss of consciousness was the main clinical symptom. Mild and mainly systolic orthostatic hypotension was recorded in 17.6%; evidence of sympathetic or parasympathetic dysfunction was found in none.

CONCLUSIONS

CSH was confirmed in patients > 50 years, the incidence steeply increasing with age. The current European Society of Cardiology guidelines that recommend testing for CSH in all patients > 40 years with syncope of unknown aetiology may need reconsideration. Orthostatic hypotension was noted in some patients with CSH, but evidence of sympathetic or parasympathetic failure was not found in any of them.

Multiple system atrophy and autonomic failure

Multiple system atrophy (MSA) is a sporadic neurodegenerative disorder that affects adults. It is characterised by autonomic failure affecting many systems; cardiovascular, urinary, sexual, gastrointestinal and sudomotor, amongst others. In addition there are motor deficits, resulting in both parkinsonian and/or cerebellar features. This review will outline the clinical features, investigations and management of MSA, with a particular emphasis on autonomic failure.

EFNS guidelines on the diagnosis and management of orthostatic hypotension

Orthostatic (postural) hypotension (OH) is a common, yet under diagnosed disorder. It may contribute to disability and even death. It can be the initial sign, and lead to incapacitating symptoms in primary and secondary autonomic disorders. These range from visual disturbances and dizziness to loss of consciousness (syncope) after postural change. Evidence based guidelines for the diagnostic workup and the therapeutic management (non-pharmacological and pharmacological) are provided based on the EFNS guidance regulations. The final literature research was performed in March 2005. For diagnosis of OH, a structured history taking and measurement of blood pressure (BP) and heart rate in supine and upright position are necessary. OH is defined as fall in systolic BP below 20 mmHg and diastolic BP below 10 mmHg of baseline within 3 min in upright position. Passive head-up tilt testing is recommended if the active standing test is negative, especially if the history is suggestive of OH, or in patients with motor impairment. The management initially consists of education, advice and training on various factors that influence blood pressure. Increased water and salt ingestion effectively improves OH. Physical measures include leg crossing, squatting, elastic abdominal binders and stockings, and careful exercise. Fludrocortisone is a valuable starter drug. Second line drugs include sympathomimetics, such as midodrine, ephedrine, or dihydroxyphenylserine. Supine hypertension has to be considered.

Skin vasomotor reflex responses in two contrasting groups of autonomic failure

BACKGROUND & AIM

A variety of stimuli such as deep inspiration, isometric exercise and mental arithmetic, result in a transient vasoconstriction,mediated by sympathetic efferent nerves, in the skin of the fingers and toes of healthy controls (Skin Vasomotor Reflex: SkVR). Multiple system atrophy (MSA) and pure autonomic failure (PAF) provide contrasting models of autonomic failure. In MSA the lesion is central and preganglionic, whilst in PAF the lesion site is peripheral and postganglionic. We evaluated the SkVR in response to various stimuli in MSA and PAF, to determine differences in skin vasomotor involvement between these two patient groups.

METHODS

25 subjects (10 MSA, 7 PAF, 8 healthy controls) were studied. Baseline recordings of skin blood flow were obtained with a laser Doppler probe on the left index finger pulp and forearm. The subject then underwent a variety of stimuli with rest periods in between to reestablish baseline SkBF. These stimuli were: single deep inspiration (inspiratory gasp); mental arithmetic; bilateral leg elevation and cutaneous cold.

RESULTS

Healthy control subjects demonstrated marked SkVRs on the finger pulp to each of the stimuli of a magnitude similar to those seen in previous studies, but no SkVRs on the forearm. In MSA SkVRs to inspiratory gasp on the finger pulp were reduced relative to controls. In PAF SkVRs were reduced relative to controls or MSA. The magnitude of SkVR response to gasp and cutaneous cold in PAF was significantly less than in healthy controls. In addition, the magnitude of the response in PAF was significantly less than in MSA for inspiratory gasp.

CONCLUSIONS

PAF showed a decreased SkVR response to all 4 stimuli, the response being significantly less than controls (for inspiratory gasp and cutaneous cold) or MSA (cutaneous cold inspiratory gasp). The decreased responses in PAF may reflect the extensive postganglionic sympathetic denervation seen in this group. The measurement of SkVR may therefore provide a non-invasive aid to the differentiation of MSA and PAF.

Long-term outcome of high-dose melphalan and autologous stem cell transplantation for AL amyloidosis

Light chain (AL) amyloidosis is the result of a clonal plasma cell expansion, in which amyloidogenic monoclonal light chains deposit in various tissues resulting in organ dysfunction and organ failure. The median survival of patients with AL amyloidosis without therapy is 10-14 months. Several phase II studies report haematological and clinical remission in up to 50% of patients after high-dose melphalan and autologous stem cell transplantation. We analysed retrospectively the long-term outcome of 19 patients treated in this way between August/1996 and December/2001. We observed a relatively high treatment-related mortality of 26%, but 12 patients (63%) were high-risk candidates. Eight patients (42%) surviving longer than 100 days achieved haematological remission and long-term survival, whereas 6 (32%) obtained no clear benefit from high-dose therapy. However, 62% of patients survived beyond 2 years and the median survival from transplant was 48 months (range 0-104 months).

Heat-provoked skin vasodilatation in innervated and denervated trunk dermatomes in human spinal cord injury

STUDY DESIGN

Cross-sectional, observational, controlled study.

OBJECTIVE

High spinal cord injury (SCI) results in disruption of sympathetic vasomotor control. Vasodilatation as a response to local heating is a biphasic mechanism: the first phase (neurogenic) is mediated by the axon-reflex and is modulated by activity of sympathetic nerves. Our objective was to determine whether the response to heat provocation in trunk dermatomes may provide a measure of vasomotor sympathetic function in SCI.

SETTING

National Spinal Injuries Centre, Stoke Mandeville Hospital, Buckinghamshire, UK; Autonomic Unit, The National Hospital for Neurology and Neurosurgery, Queen Square, London, UK; Neurovascular Medicine Unit, Imperial College London at St Mary's Hospital, UK.

SUBJECTS

A total of 30 subjects were studied; 18 had chronic complete SCI (level C6-T11) and 12 were healthy controls.

METHODS

Recordings of skin blood flow (SkBF) were obtained with thermostatic laser Doppler probes placed in the upper trunk (at C4) and lower trunk (T10 or T12) dermatomes.

RESULTS

SkBF at baseline (SkBF(bas)) and SkBF at the first peak of vasodilatation (SkBF(max)) showed no significant differences between SCI and controls either in upper or lower trunk dermatomes. However, the ratio of SkBF(max)/SkBF(bas) was significantly different in lower trunk dermatomes in SCI at C6-T5 level (7.5+/-3.5 PU) compared to SCI at T6-T11 level (3.5+/-1.5 PU) (P < 0.01).

CONCLUSION

Measurement of SkBF in response to local heating may provide a safe, noninvasive method to assess integrity of sympathetic spinal pathways to the local vasculature. This may aid the classification of the SCI lesions, as the autonomic component currently is not included in the accepted American Spinal Injury Association scoring.

Evaluation of antioxidant activity of Brazilian plants

In this work, 22 alcoholic extracts, obtained from 14 species of plants belonging to four families, used for different food and medicinal purposes in Brazil, were evaluated for their capacity to inhibit the reduction of the free radical, 1,1-diphenyl-2-picrylhydrazyl (DPPH), and to protect Saccharomyces cerevisiae cells, an eukaryotic cell model, against the lethal oxidative stress caused by tert-butylhydroperoxide (TBH). Five extracts, two from Lamiaceae family (ethanol and butanol extracts from aerial parts of Hyptis fasciculata) and three from Palmae family (Copernicia cerifera leaves and mesocarp of fruits and the endocarp/mesocarp of fruits from Orbignya speciosa) were able to increase the tolerance of S. cerevisiae to TBH and showed to be active as DPPH radical scavengers, thus indicating that these plant extracts could be considered as potential sources of antioxidants. With the exception of ethanol extract of H. fasciculata, the remainder four extracts exhibited a DPPH radical scavenging activity higher than that obtained from Ginkgo biloba, a reference plant with well documented antioxidant activity. Interestingly, the ethanol extract of G. biloba were not effective for yeast cell protection, reinforcing the antioxidant potential of these extracts.

Syncope associated with pain as the presenting feature of neck malignancy: failure of cardiac pacemaker to prevent attacks in two cases

Two patients are described in whom syncope was the presenting clinical feature of an undiagnosed neck malignancy. Both patients also had attacks associated with paroxysms of severe neck pain. Neither patient responded to cardiac pacing.

The European Multiple System Atrophy-Study Group (EMSA-SG)

Introduction. The European Multiple System Atrophy-Study Group (EMSA-SG) is an academic network comprising 23 centers across Europe and Israel that has constituted itself already in January 1999. This international forum of established experts under the guidance of the University Hospital of Innsbruck as coordinating center is supported by the 5th framework program of the European Union since March 2001 (QLK6-CT-2000-00661). Objectives. Primary goals of the network include (1) a central Registry for European multiple system atrophy (MSA) patients, (2) a decentralized DNA Bank, (3) the development and validation of the novel Unified MSA Rating Scale (UMSARS), (4) the conduction of a Natural History Study (NHS), and (5) the planning or implementation of interventional therapeutic trials. Methods. The EMSA-SG Registry is a computerized data bank localized at the coordinating centre in Innsbruck collecting diagnostic and therapeutic data of MSA patients. Blood samples of patients and controls are recruited into the DNA Bank. The UMSARS is a novel specific rating instrument that has been developed and validated by the EMSA-SG. The NHS comprises assessments of basic anthropometric data as well as a range of scales including the UMSARS, Unified Parkinson's Disease Rating Scale (UPDRS), measures of global disability, Red Flag list, MMSE (Mini Mental State Examination), quality of live measures, i.e. EuroQoL 5D (EQ-5D) and Medical Outcome Study Short Form (SF-36) as well as the Beck Depression Inventory (BDI). In a subgroup of patients dysautonomic features are recorded in detail using the Queen Square Cardiovascular Autonomic Function Test Battery, the Composite Autonomic Symptom Scale (COMPASS) and measurements of residual urinary volume. Most of these measures are repeated at 6-monthly follow up visits for a total study period of 24 months. Surrogate markers of the disease progression are identified by the EMSA-SG using magnetic resonance and diffusion weighted imaging (MRI and DWI, respectively). Results. 412 patients have been recruited into the Registry so far. Probable MSA-P was the most common diagnosis (49% of cases). 507 patients donated DNA for research. 131 patients have been recruited into the NHS. There was a rapid deterioration of the motor disorder (in particular akinesia) by 26.1% of the UMSARS II, and - to a lesser degree - of activities of daily living by 16.8% of the UMSARS I in relation to the respective baseline scores. Motor progression was associated with low motor or global disability as well as low akinesia or cerebellar subscores at baseline. Mental function did not deteriorate during this short follow up period. Conclusion. For the first time, prospective data concerning disease progression are available. Such data about the natural history and prognosis of MSA as well as surrogate markers of disease process allow planning and implementation of multi-centre phase II/III neuroprotective intervention trials within the next years more effectively. Indeed, a trial on growth hormone in MSA has just been completed, and another on minocycline will be completed by the end of this year.

Skin vasodilator response to local heating in human chronic spinal cord injury

Local heating evokes an increase in skin blood flow (SkBF), which consists of an initial peak (axon-reflex mediated) followed by a brief nadir and a secondary rise to a plateau. The aim of this study was to investigate whether heat provoked vasodilatation detects sympathetic vasomotor dysfunction and completeness of injury in patients with spinal cord injury (SCI). Twelve (seven complete, and five incomplete; level C4-L4) SCI patients, and nine healthy subjects as controls were studied. Thermostatic laser Doppler probes, which heat the skin locally, were placed on the dorsum of the hand and foot. SkBF was measured by laser Doppler flowmetry at baseline and at the first peak of vasodilatation (SkBF(max)). On the hand, SkBF at baseline and SkBF(max) were similar between the three groups. On the foot, SkBF at baseline was similar between the three groups but SkBF(max) was significantly diminished in complete SCI patients compared with controls (P < 0.01). In conclusion, heat provoked axon-reflex vasodilatation was diminished in the foot, below the level of lesion, in complete SCI. This test, that evaluates localized sympathetic vasomotor dysfunction, may be a useful non-invasive technique to detect completeness of autonomic disruption after SCI.

The effects of water ingestion on orthostatic hypotension in two groups of chronic autonomic failure: multiple system atrophy and pure autonomic failure

BACKGROUND

Oral ingestion of water increases seated blood pressure in patients with chronic autonomic failure by mechanisms that remain unclear. As orthostatic hypotension is common in chronic autonomic failure, and is not always adequately controlled by medication, the potential benefits of water ingestion on standing blood pressure were studied in two types of autonomic failure: multiple system atrophy (MSA), in which the lesion is central and pre-ganglionic, and pure autonomic failure (PAF), in which the lesion is post-ganglionic.

METHODS

In 14 patients with autonomic failure (seven PAF and seven MSA) standing blood pressure and heart rate were measured before, and 15 and 35 minutes after ingestion of 480 ml distilled water. Patients remained seated for 15 minutes after water ingestion, with beat to beat cardiovascular indices measured with the Portapres II device with subsequent Modelflow analysis.

RESULTS

Standing prior to water ingestion caused a significant fall in blood pressure in all patients. After water ingestion there was a rise in seated blood pressure. Seated and standing blood pressure at 15 and 35 minutes after water ingestion was significantly higher than before water, with an improvement in orthostatic symptoms. The time to first significant rise in seated blood pressure occurred at 5 minutes post water ingestion in PAF and at 13 minutes in MSA. These increases were accompanied by increases in total peripheral resistance, reaching significance by 5 minutes in PAF and 13 minutes in MSA. There were no significant changes in cardiac output, stroke volume, or ejection fraction.

CONCLUSIONS

Water is thus beneficial in improving standing BP in AF, acting within 15 minutes in both MSA and PAF. The earlier onset of the pressor effect in PAF may reflect the differing lesion site and underlying pathophysiology between these conditions.

Water drinking in the management of orthostatic intolerance due to orthostatic hypotension, vasovagal syncope and the postural tachycardia syndrome

Water drinking recently has been shown to raise blood pressure in normal subjects and in patients with autonomic failure who have orthostatic hypotension. However, in normal young subjects, ingestion of approximately 500 ml has no pressor effect; but in older subjects there is an increase in blood pressure. An even greater rise in blood pressure occurs in cases with autonomic failure. The possible mechanisms responsible for the pressor response to water include neural and humoral factors; fluid redistribution also needs to be considered. This review will concentrate on the water pressor response in normal subjects and different groups of patients with autonomic diseases who have orthostatic intolerance, on the mechanisms that could be involved, and on whether this pressor response may be used in the management of orthostatic hypotension, vasovagal syncope and the postural tachycardia syndrome.

Social and motivational functioning is not critically dependent on feedback of autonomic responses: neuropsychological evidence from patients with pure autonomic failure

Social, emotional and motivational behaviours are associated with production of automatic bodily responses. Re-representation in the brain through feedback of autonomic and skeletomuscular arousal is proposed to underlie "feeling states". These influence emotional judgments and bias motivational decision-making and guide social interactions. Consistent with this hypothesis, dissocial behaviour and deficits on emotional and motivation tasks are associated with blunted bodily responses in patients with orbitofrontal brain lesions or developmental psychopathy. To determine the critical dependence of social and emotional behaviours on bodily responses mediated by the autonomic nervous system, we examined patients with pure autonomic failure (PAF), a peripheral denervation of autonomic neurons with onset in middle age. Compared to healthy subjects, PAF patients were unimpaired on tests of motivational decision-making (Iowa Gambling Task), recognition of emotional facial expressions, Theory of Mind Tasks and tests of social cognition. Only on a test of emotional attribution, which is perhaps more sensitive to subjective feeling states, did PAF patients score worse than the comparison group, though there was no evidence that this deficit was specific to a discrete emotion and requires further validation. These findings suggest that emotional and social functioning is not critically tied to on-going experience of autonomic arousal state, Acquisition of autonomic failure late in life may protect against maladaptive social behaviour through established behavioural responses that may be associated with central "as if" representations.

[11C](R)-PK11195 PET imaging of microglial activation in multiple system atrophy

Microglia, the brain's intrinsic macrophages, bind (R)-PK11195 when activated by neuronal injury. The authors used [11C](R)-PK11195 PET to localize in vivo microglial activation in patients with multiple system atrophy (MSA). Increased [11C](R)-PK11195 binding was primarily found in the dorsolateral prefrontal cortex, putamen, pallidum, pons, and substantia nigra, reflecting the known distribution of neuropathologic changes in MSA. Providing an indicator of disease activity, [11C](R)-PK11195 PET can thus be used to characterize the in vivo neuropathology of MSA.

Erectile and urinary dysfunction may be the presenting features in patients with multiple system atrophy: a retrospective study

Multiple system atrophy (MSA) is a progressive neurodegenerative disease characterized by parkinsonism and cerebellar, autonomic, urinary, and/or pyramidal dysfunction. Urinary and erectile dysfunction (ED) symptoms are prominent early features in men with MSA. Autonomic failure, considered until recently to be the cause of ED in these men, is commonly expressed through symptoms of orthostatic hypotension (OH). The aim of this retrospective study is to examine the chronological relationship between the development of urogenital symptoms and those of OH in patients diagnosed with MSA and discuss its significance in the aetiology of ED in these patients. A total of 71 male patients, referred to a Uro-Neurology department with a diagnosis of 'probable MSA', were reviewed in terms of 'autonomic' symptoms only--OH and lower urinary tract symptoms, accompanied by ED--present at the time of their referral. Laboratory investigations including anal sphincter EMG and/or autonomic function tests (AFTs) were performed in 75 and 90% of the patients, respectively. At presentation, urinary complaints were recorded in 96% of patients and ED in all patients that this was inquired about. The onset of ED had preceded the onset of bladder symptoms in 58% and the onset of OH symptoms in 91% of these men. Bladder symptoms also preceded symptoms of OH in 76% of patients. Sphincter EMG was abnormal in 91% and AFTs in 77% of the patients tested. Almost all patients with abnormal EMG had troublesome urinary symptoms. AFTs showed similar sensitivity relating to symptoms. At presentation, urogenital symptoms are common in patients with probable MSA and are often not accompanied by symptoms of OH. The earlier occurrence of ED in men with MSA suggests a lack of a causal relationship to hypotension. The notion that MSA possibly affects the dopaminergic mechanism of erectile function is discussed.

Cardiovascular autonomic function in systemic lupus erythematosus

AIM

To determine whether cardiovascular autonomic function is impaired in systemic lupus erythematosus (SLE).

METHODS

A case-control study of 23 patients with SLE was performed. Autonomic symptoms were assessed using a standard questionnaire. Cardiovascular autonomic function was measured using 10 non-invasive investigations. There were significant differences between patients and controls in three out of 24 parameters measured during the different tests (P < 0.002). These were reduction in systolic blood pressure at 5 min on head-up tilt, and heart rate responses to isometric exercise and cutaneous cold. Eleven out of 23 patients had an abnormal heart rate, blood pressure or Valsalva response (value below the age corrected 5th centile) while testing compared with six of the controls. Plasma adrenaline and noradrenaline levels were significantly lower in patients vs controls in both the supine (P < 0.05) and tilt position (P < 0.01). Twenty-one of the 23 patients had one or more symptoms that may be attributable to abnormalities in autonomic function. There was no significant association between the number of symptoms and presence of autonomic dysfunction. Cardiovascular autonomic impairment may be demonstrated in some patients with SLE. Symptoms attributable to autonomic dysfunction are common in SLE and autonomic assessment may be required.

Do published criteria improve clinical diagnostic accuracy in multiple system atrophy?

OBJECTIVE

To assess the accuracy of a clinical diagnosis of multiple system atrophy (MSA) and compare it to the Quinn and Consensus criteria for MSA using neuropathologically examined cases from the Queen Square Brain Bank for Neurological Disorders.

METHODS

Fifty-nine cases with a neurologic diagnosis of MSA when last assessed prior to death were studied.

RESULTS

In 51 (86%) of these cases, the diagnosis of MSA was confirmed pathologically. False positive diagnoses included PD (n = 6), progressive supranuclear palsy (n = 1), and cerebrovascular disease (n = 1). When applying either set of diagnostic criteria, a diagnosis of probable MSA gave lower sensitivity but higher positive predictive value than one of possible MSA. Application of either set of diagnostic criteria was superior to actual clinical diagnosis made early in the disease, but there was little difference by the last clinic visit.

CONCLUSIONS

This study shows a high diagnostic accuracy for the clinical diagnosis of MSA by neurologists, with PD accounting for most of the false positive diagnoses. Application of either Quinn or Consensus criteria was superior to actual clinical diagnosis made early in the disease, but there was little difference by last clinic visit.

Organisation of the sympathetic skin response in spinal cord injury

OBJECTIVES

The sympathetic skin response (SSR) is a technique to assess the sympathetic cholinergic pathways, and it can be used to study the central sympathetic pathways in spinal cord injury (SCI). This study investigated the capacity of the isolated spinal cord to generate an SSR, and determined the relation between SSR, levels of spinal cord lesion, and supraspinal connections.

METHODS

Palmar and plantar SSR to peripheral nerve electrical stimulation (median or supraorbital nerve above the lesion, and peroneal nerve below the lesion) were recorded in 29 patients with SCI at various neurological levels and in 10 healthy control subjects.

RESULTS

In complete SCI at any neurological level, SSR was absent below the lesion. Palmar SSR to median nerve stimuli was absent in complete SCI with level of lesion above T6. Plantar SSR was absent in all patients with complete SCI at the cervical and thoracic level. In incomplete SCI, the occurrence of SSR was dependent on the preservation of supraspinal connections. For all stimulated nerves, there was no difference between recording from ipsilateral and contralateral limbs.

CONCLUSIONS

No evidence was found to support the hypothesis that the spinal cord isolated from the brain stem could generate an SSR. The results indicate that supraspinal connections are necessary for the SSR, together with integrity of central sympathetic pathways of the upper thoracic segments for palmar SSR, and possibly all thoracic segments for plantar SSR.

The prevalence and association of neck (coat-hanger) pain and orthostatic (postural) hypotension in human spinal cord injury

OBJECTIVE

To investigate the prevalence of orthostatic (postural) hypotension (OH) and neck pain in a 'coat-hanger' occipito-cervical distribution in subjects with spinal cord injury (SCI), and their association.

METHOD

Blood pressure was measured during head-up tilt to 60 degrees (to determine OH) and neck pain was assessed in 28 subjects with SCI (cervical, thoracic and lumbar level) with McGill Pain Questionnaire, visual analogue scale for pain intensity and Orthostatic Intolerance Symptoms Questionnaire for pain frequency.

RESULTS

Neck pain was reported by 53.6% of subjects. Orthostatic hypotension was present in 57.1% of subjects. Neck pain was reported by 75% of subjects with OH and 25% of subjects without OH (P<0.03, Chi-square). Features of such pain included positive correlation to upright posture and exercise, and relief when lying flat.

CONCLUSION

There is a high prevalence of neck pain and OH in SCI, with a positive association similar to that reported in primary autonomic failure with OH.

Cardiovascular and neurohormonal responses to i. v. l-arginine in two groups with primary autonomic failure

Nitric oxide (NO) is synthesised from the amino-acid l-arginine by the enzyme nitric oxide synthetase (NOS) and modulates a wide variety of neural, cardiovascular and hormonal processes. Cardiovascular autonomic dysfunction and impaired neurohormonal secretion characterise patients with primary chronic autonomic failure (AF). To investigate the role of NO, we studied the cardiovascular and neurohormonal effects of intravenous (i. v.) l-arginine (0.5 g/kg) in 20 patients with AF: [10 with multiple system atrophy (MSA) and 10 patients with pure autonomic failure (PAF)] and compared them with age-matched healthy normal subjects. Basal mean arterial pressure (MAP) was higher in MSA and PAF than controls (p < 0.02). Following l-arginine, MAP fell in MSA (mean: -39 +/- 8 mmHg, 95 % CI -21 to -57, p < 0.05) and PAF (-37 +/- 5,95 % CI -26 to -58, p < 0.05) but not in controls. There were no significant changes in HR between the groups. Basal plasma noradrenaline (NA) was similar in controls and MSA, but lower in PAF (p < 0.05). Following l-arginine the percentage rise in plasma NA was similar in controls and MSA, but not in PAF (p < 0.05). Plasma insulin rose similarly in controls and MSA, but was higher in PAF (p < 0.05). Plasma glucose rose to a similar level in all groups. In conclusion, l-arginine, lowered BP in both MSA and PAF. In PAF a contributory factor may be increased insulin release, without a compensatory increase in sympatho-neural activity to counter its potential vasodilator effects. These studies suggest that reducing NO levels, as with NOS inhibitors, may be of benefit in the treatment of postural hypotension and possibly post-prandial hypotension in chronic primary AF.

Characteristics of habituation of the sympathetic skin response to repeated electrical stimuli in man

OBJECTIVES

To study the effect of repeating electrical peripheral nerve stimulation on latency, duration and amplitude of the sympathetic skin response (SSR).

METHODS

SSRs were elicited in all limbs by median and peroneal nerves stimuli. In 10 subjects, 20 stimuli were applied at random time intervals (15-20 s). Another test was performed in 7 subjects using the same protocol, but switching the stimulation site every 5 or 10 stimuli without warning.

RESULTS

The mean amplitude of right palmar response to right peroneal nerve stimulation decreased from 5.05+/-0.76 (SEM) mV at the first stimulus to 1.23+/-0.42 mV at the 20th stimulus (P<0.001). The latency did not change significantly (1473+/-82 to 1550+/-90 ms, P>0.1), while the duration increased (1872+/-356 to 3170+/-681 ms, P<0.001). Stimulation and recording at other sites showed similar trends. Changing the stimulation site failed to alter the adaptation process in terms of amplitude, latency or duration.

CONCLUSIONS

Changes in amplitude and duration of the SSRs to repeated electrical stimuli can occur in presence of constant latency and appear to be independent of the source of sensory input. Peripheral sweat gland mechanisms may be involved in the loss of amplitude and increase in duration of the SSR during habituation.

Treatment of erectile dysfunction with sildenafil citrate (Viagra) in parkinsonism due to Parkinson's disease or multiple system atrophy with observations on orthostatic hypotension

OBJECTIVES

To assess the efficacy and safety of sildenafil citrate (Viagra) in men with erectile dysfunction and parkinsonism due either to Parkinson's disease or multiple system atrophy.

METHODS

Twenty four patients with erectile disease were recruited, 12 with Parkinson's disease and 12 with multiple system atrophy, into a randomised, double blind, placebo controlled, crossover study of sildenafil citrate. The starting dose was 50 mg active or placebo medication with the opportunity for dose adjustment depending on efficacy and tolerability. The international index of erectile function questionnaire (IIEF) was used to assess treatment efficacy and a quality of life questionnaire to assess the effect of treatment on sex life and whole life. Criteria for entry included a definite neurological diagnosis and a standing systolic blood pressure of 90-180 mm Hg and diastolic blood pressure of 50-110 mm Hg, on treatment if necessary. Blood pressure was taken at randomisation (visit 2) and crossover (visit 5) lying, sitting, and standing, before and 1 hour after taking the study medication in hospital.

RESULTS

Sidenafil citrate was efficacious in men with parkinsonism with a significant improvement, as demonstrated in questionnaire responses, in ability to achieve and maintain an erection and improvement in quality of sex life. In Parkinson's disease there was minimal change in blood pressure between active and placebo medication. In multiple system atrophy, six patients were studied before recruitment was stopped because three men showed a severe drop in blood pressure 1 hour after taking the active medication. Two were already known to have orthostatic hypotension and were receiving treatment with ephedrine and midodrine but the third had asymptomatic hypotension. However, the blood pressures in all three had been within the inclusion criterion for the study protocol. Despite a significant postural fall in blood pressure after sildenafil, all patients with multiple system atrophy reported a good erectile response and were reluctant to discontinue the medication.

CONCLUSIONS

Sidenafil citrate (50 mg) is efficacious in the treatment of erectile dysfunction in parkinsonism due to Parkinson's disease or multiple system atrophy; however, it may unmask or exacerbate hypotension in multiple system atrophy. As Parkinson's disease may be diagnostically difficult to distinguish from multiple system atrophy, especially in the early stages, we recommend measurement of lying and standing blood pressure before prescribing sildenafil to men with parkinsonism. Furthermore, such patients should be made aware of seeking medical advice if they develop symptoms on treatment suggestive of orthostatic hypotension.

Haemodynamics of the pressor effect of oral water in human sympathetic denervation due to autonomic failure

Oral water ingestion increases blood pressure in normal elderly subjects and in patients suffering from autonomic failure, but the time course of the haemodynamic changes is not known. We therefore studied 14 subjects with documented sympathetic denervation due to pure autonomic failure, with continuous haemodynamic recordings obtained before and after ingestion of 500 ml of distilled water at room temperature. The time course of changes in values of systolic and diastolic beat-by-beat finger blood pressure, heart rate, stroke volume, cardiac output, ejection fraction and total peripheral resistance were analysed. Systolic blood pressure rose from 115+/-8 mmHg (mean+/-S.E.M.) to 133+/-8 mmHg (P<0.001), and diastolic blood pressure from 64+/-4 to 73+/-4 mmHg (P<0.001), with the pressor response beginning a few minutes after water ingestion, plateauing between 10 and 35 min (peak at 14 min), and returning to baseline at 50 min. Heart rate fell from 71+/-2.5 to 67+/-2 beats/min (P<0.001), and total peripheral resistance increased from 1.31+/-0.19 to 1.61+/-0.24 m-units (P<0.001). There were no significant changes in ejection fraction, stroke volume or cardiac output. This study confirmed a pressor response to oral water in subjects with sympathetic denervation. The temporal profile of the response did not favour reflexly mediated sympathetic activation. As subjects with autonomic failure are prone to salt and water depletion, and since blood pressure is exquisitely sensitive to such changes, it may be that the observed response is due to repletion or restoration of intravascular and extravascular fluid volume.

L-threo-dihydroxyphenylserine (L-threo-DOPS; droxidopa) in the management of neurogenic orthostatic hypotension: a multi-national, multi-center, dose-ranging study in multiple system atrophy and pure autonomic failure

This study was designed to determine the efficacy and tolerability of increasing doses of L-threo-dihydroxyphenylserine (L-threo-DOPS) in treating symptomatic orthostatic hypotension associated with multiple system atrophy (MSA) and pure autonomic failure (PAF). Following a one-week run-in, patients (26 MSA; 6 PAF) with symptomatic orthostatic hypotension received increasing doses of L-threo-DOPS (100, 200 and 300 mg, twice daily) in an open, dose-ranging study. Incremental dose adjustment (after weeks two and four of outpatient treatment) was based on clinical need until blood pressure (BP), and symptoms improved. Final dosage was maintained for six weeks. With L-threo-DOPS, systolic BP decrease was reduced during orthostatic challenge (-22+/-28 mm Hg reduction from a baseline decrease of 54.3+/-27.7 mm Hg, p = 0.0001, n = 32; supine systolic BP at final visit was 118.9+/-28.2 mm Hg). By the end of the study, 25 patients (78%) improved, and in 14 patients (44%) orthostatic hypotension was no longer observed. Decreased orthostatic systolic BP decrease occurred in 22% (7/32), 24% (6/25) and 61% (11/18) of patients treated with 100, 200, and 300 mg L-threo-DOPS twice daily, respectively. An improvement occurred in symptoms associated with orthostatic hypotension, such as light-headedness, dizziness (p = 0.0125), and blurred vision (p = 0.0290). L-threo-DOPS was well tolerated, with the 2 serious adverse events reported being a possible complication of the disease under study, and with no reports of supine hypertension. In conclusion, L-threo-DOPS (100, 200, and 300 mg, twice daily) was well tolerated. The dosage of 300 mg twice daily L-threo-DOPS seemed to offer the most effective control of symptomatic orthostatic hypotension in MSA and PAF.

The metabolic, catecholamine and cardiovascular effects of exercise in human sympathetic denervation

The cardiovascular and metabolic responses to supine leg exercise were measured in 9 healthy subjects (controls) and in 19 subjects with two primary forms of autonomic failure (11 with peripheral sympathetic denervation [pure autonomic failure; PAF], 8 with central sympathetic failure [multiple system atrophy; MSA]). With exercise, blood pressure increased in controls and fell markedly in subjects with PAF and MSA. Blood pressure returned to baseline in controls, but remained low in the PAF and MSA groups. With exercise, heart rate increased more in controls than the PAF and MSA groups. Resting plasma noradrenaline concentrations in controls and in subjects with MSA were similar, but were lower in subjects with PAF. With exercise, plasma noradrenaline concentrations increased in controls and were unchanged in subjects with PAF; there was no significant increase in the MSA group. Resting plasma lactate, pyruvate and lactate/pyruvate ratios were similar in all three groups. With exercise, lactate concentrations increased until 2 minutes post exercise in all groups. Pyruvate concentrations after 9 minutes' exercise were higher in controls than in the PAF group but were similar to the MSA group; thereafter, concentrations increased similarly in all groups. The lactate/pyruvate ratio increased until 2 minutes post exercise in all groups. Resting plasma free fatty acids, and beta-hydroxybutyrate were similar in all groups. Plasma glycerol concentrations in control and MSA subjects were similar; concentrations were lower in PAF subjects. With exercise, plasma free fatty acids and glycerol concentrations remained unchanged in all groups; beta-hydroxybutyrate concentrations decreased less in control subjects than in PAF and MSA subjects. In conclusion, there were similar concentrations of plasma free fatty acids, glycerol and beta-hydroxybutyrate in control, PAF and MSA subjects; this could indicate up-regulation of beta-receptors in AF, or that sympathetic activity plays a smaller role in lipolysis. Plasma lactate and pyruvate concentrations increased similarly in all groups, despite marked differences in BP; this suggested an impairment of production or clearance of lactate in AF. A role for lactate-induced vasodilatation, not compensated for by sympathetic vasoconstriction, remains speculative.

Brain activity during biofeedback relaxation: a functional neuroimaging investigation

The mechanisms by which cognitive processes influence states of bodily arousal are important for understanding the pathogenesis and maintenance of stress-related morbidity. We used PET to investigate cerebral activity relating to the cognitively driven modulation of sympathetic activity. Subjects were trained to perform a biofeedback relaxation exercise that reflected electrodermal activity and were subsequently scanned performing repetitions of four tasks: biofeedback relaxation, relaxation without biofeedback and two corresponding control conditions in which the subjects were instructed not to relax. Relaxation was associated with significant increases in left anterior cingulate and globus pallidus activity, whereas no significant increases in activity were associated with biofeedback compared with random feedback. The interaction between biofeedback and relaxation, highlighting activity unique to biofeedback relaxation, was associated with enhanced anterior cingulate and cerebellar vermal activity. These data implicate the anterior cingulate cortex in the intentional modulation of bodily arousal and suggest a functional neuroanatomy of how cognitive states are integrated with bodily responses. The findings have potential implications for a mechanistic account of how therapeutic interventions, such as relaxation training in stress-related disorders, mediate their effects.

Age- and gender-related growth hormone responses to intravenous clonidine in healthy adults

The alpha(2)-adrenoceptor agonist clonidine stimulates growth hormone (GH) release in both animals and humans. It has been used to test for GH deficiency in children, to assess central alpha(2)-adrenoceptor function in adults and to determine the pathophysiological basis and to confirm diagnosis in neurological diseases with autonomic failure. The dose and mode of administration, however, may be important, as in some studies in adults oral clonidine has minimal effects on GH. We report our experience following intravenous (i.v.) clonidine (2 microg/kg) in 98 normal adults on the neuroendocrine (GH, insulin, glucose and catecholamine) and cardiovascular (blood pressure) responses. In males between 25 and 89 years and females between 25 and 64 years there was a significant rise in GH secretion (P < 0.05) after clonidine. Males showed an age-sensitive secretory pattern, with the greatest response between 25 and 35 years (P < 0.02). Younger males (< 45 years) had significantly higher peak GH levels post-clonidine than younger females < 45 years (P < 0.03). No sex-related change was observed in older subjects (< 45 years). Clonidine caused a significant fall in plasma noradrenalin and adrenalin in all age-sex groups (P< 0.001). There were no significant changes in glucose or insulin. There were no effects of age on the fall in blood pressure induced by clonidine. In conclusion, i.v. clonidine stimulated GH in all age groups and there was a marked sexually dimorphic pattern in adults < 45 years. The results overall suggest that i.v. clonidine-GH testing provides a reliable method for investigation of central alpha(2)-adrenergic function in adult humans.

A novel TRK A (NTRK1) mutation associated with hereditary sensory and autonomic neuropathy type V

A boy with recurrent pyrexial episodes from early life sustained a painless ankle injury and was found to have a calcaneus fracture and, later, neuropathic joint degeneration of the tarsus. Examination revealed distal loss of pain and temperature sensation and widespread anhidrosis. Sural nerve biopsy demonstrated severe reduction in small-caliber myelinated fiber density but only modest reduction in unmyelinated axons, the pattern of type V hereditary sensory and autonomic neuropathy (HSAN V). DNA analysis showed that he was homozygous for a mutation in the NTRK1/high-affinity nerve growth factor (TrkA) gene, his parents being heterozygous. Mutations in this gene are known to be responsible for HSAN IV (congenital insensitivity to pain with anhidrosis). The two disorders are therefore likely to be allelic.

Observations on recurrent syncope and presyncope in 641 patients

BACKGROUND

Syncope is a common disorder that is potentially disabling and affects both young and old. Once neurological, cardiological, and metabolic causes have been excluded, there remains a group in which diagnosis is unclear; some may have an autonomic basis. We therefore did a retrospective study on consecutive patients referred to our tertiary referral autonomic centres between 1992 and 1998 with recurrent syncope and presyncope, in whom non-autonomic causes, before referral, had been sought and excluded. The object was to find out whether autonomic investigation helped diagnosis.

METHODS

Data from case notes and from the autonomic database on 641 patients were analysed. Syncopal patients with a known or provisional diagnosis of autonomic failure were excluded from analysis. The role of screening tests in establishing or excluding an autonomic cause was assessed. Response to additional autonomic tests (such as head-up tilt with or without venepuncture, and food challenge and exercise) was documented. Some patients underwent further testing if non-autonomic neurological, psychiatric, and other disorders were considered.

FINDINGS

Screening autonomic function tests indicated orthostatic hypotension and confirmed chronic autonomic failure in 31 (4.8%) patients. Neurally mediated syncope was diagnosed in 279 (43.5%) on the basis of clinical features and autonomic testing. Most had vasovagal syncope (227 [35%]); other causes included carotid sinus hypersensitivity (37 [5.8%]), and a group of 15 (2.3%) were associated with rarer causes such as micturition and swallowing. Miscellaneous cardiovascular causes (systemic hypotension, arrhythmias), or drugs, contributed to syncope in 53 (8.3%). Non-autonomic neurological causes included vestibular dysfunction (32 [5%]) and epilepsy (11 [1.7%]). In 56 (8.7%) a psychiatric cause was thought to be contributory. In 179 (27.9%), syncope was of unknown cause.

INTERPRETATION

In recurrent syncope and presyncope, when cardiac, neurological, and metabolic causes have been excluded, autonomic investigation can aid management by making, confirming, or excluding various factors or diagnoses.

Neuroanatomical basis for first- and second-order representations of bodily states

Changes in bodily states, particularly those mediated by the autonomic nervous system, are crucial to ongoing emotional experience. A theoretical model proposes a first-order autoregulatory representation of bodily state at the level of dorsal pons, and a second-order experience-dependent re-mapping of changes in bodily state within structures such as cingulate and medial parietal cortices. We tested these anatomical predictions using positron emission tomography and a human neurological model (pure autonomic failure), in which peripheral autonomic denervation prevents the emergence of autonomic responses. Compared to controls, we observed task-independent differences in activity of dorsal pons and context-induced differences in cingulate and medial parietal activity in PAF patients. An absence of afferent feedback concerning autonomically generated bodily states was associated with subtle impairments of emotional responses in PAF patients. Our findings provide empirical support for a theory proposing a hierarchical representation of bodily states.

Neural activity in the human brain relating to uncertainty and arousal during anticipation

We used functional magnetic resonance neuroimaging to measure brain activity during delay between reward-related decisions and their outcomes, and the modulation of this delay activity by uncertainty and arousal. Feedback, indicating financial gain or loss, was given following a fixed delay. Anticipatory arousal was indexed by galvanic skin conductance. Delay-period activity was associated with bilateral activation in orbital and medial prefrontal, temporal, and right parietal cortices. During delay, activity in anterior cingulate and orbitofrontal cortices was modulated by outcome uncertainty, whereas anterior cingulate, dorsolateral prefrontal, and parietal cortices activity was modulated by degree of anticipatory arousal. A distinct region of anterior cingulate was commonly activated by both uncertainty and arousal. Our findings highlight distinct contributions of cognitive uncertainty and autonomic arousal to anticipatory neural activity in prefrontal cortex.

Physiological, pharmacological and neurohormonal assessment of autonomic function in progressive supranuclear palsy

The clinical features of progressive supranuclear palsy (PSP) overlap with other parkinsonian syndromes, including multiple system atrophy (MSA). Autonomic dysfunction is a characteristic of MSA, but has also been described in PSP. We therefore report results from a series of physiological studies of cardiovascular autonomic function in 35 PSP and 20 MSA subjects, and 26 age-matched healthy control subjects. The response to growth hormone-clonidine testing, a neuropharmacological assessment of central adrenoceptor function, was also assessed in 14 PSP and 10 MSA subjects, and compared with 10 controls. None was on medication which may have affected the results. Orthostatic hypotension did not occur in PSP subjects or controls, unlike MSA subjects. Overall there was no evidence of sympathetic vasoconstrictor failure in PSP subjects, unlike MSA subjects, although the pressor response to mental arithmetic was reduced. Cardiac parasympathetic function was affected in only a minority (three of 35) of PSP subjects and was abnormal in MSA subjects. After clonidine administration, growth hormone rose in PSP subjects (median increase 4.3; interquartile range 1.8-7.8 mU/l) and controls, unlike MSA subjects (0.9; 0.3-2.4 mU/l; P < 0.005, Mann-Whitney U-test). In conclusion, in PSP subjects, responses to both physiological and pharmacological tests provided evidence against widespread autonomic dysfunction; this differed markedly from MSA subjects. Thus, cardiovascular autonomic dysfunction should be an exclusionary feature in the diagnosis of PSP.