Incidence and Case Fatality of Subarachnoid Haemorrhage in Northern Greece: The Evros Registry of Subarachnoid Haemorrhage

Background

Epidemiological data on subarachnoid haemorrhage incidence and case-fatality rates are scarce in the southeastern Mediterranean region. We conducted a population-based study in Evros Province, located in north-eastern Greece, to determine subarachnoid haemorrhage incidence over a 5-year period (2001–2005).

Methods

Evros Province has a well-defined, largely homogeneous population with healthcare organised around a single tertiary-care University Hospital. We organised a prospective computerised registry of permanent Evros residents admitted or transferred to our hospital with a diagnosis of subarachnoid haemorrhage. Standard World Health Organization definitions and overlapping case-finding methods were used to identify all cases of first ever in a lifetime subarachnoid haemorrhage in all age groups, occurring during the study period. The diagnosis was confirmed by computed tomography scan in all hospitalised cases. Sudden deaths attributable to subarachnoid haemorrhage were systematically recorded province-wide by our forensic department and are included in the study.

Results

During the 5-year period, 51 cases of subarachnoid haemorrhage were recorded (28 men, 23 women; mean age 59 ± 17 years). The crude annual incidence rates were 8·3/100000 persons (95% confidence interval: 5·5–12·0) for men, 7·5/100000 (4·8–11·3) for women and 7·9/100000 (5§9–10§4) for all subjects. The standardised incidence rates for groups aged 45–84 years in the European population were 9·3/100000 (5·8–12·8) for men, 6·5/100000 (3·7–9·4) for women and 7·9/100000 (5·7–10·2). The 28-day case-fatality rates for men, women and all subjects were 36% (21–54%), 35% (19–55%) and 35% (24–49%), respectively.

Conclusions

The incidence and case-fatality rate of subarachnoid haemorrhage haemorrhage in Greece appear to be similar to other developed countries. No gender differences in subarachnoid haemorrhage incidence and case-fatality rate were documented.

Impact of dopamine transporter single photon emission computed tomography imaging using I-123 ioflupane on diagnoses of patients with parkinsonian syndromes

To assess the impact of I-123 ioflupane single photon emission computed tomography (SPECT) imaging on classifying patients with striatal dopaminergic deficits. Sixty-one patients with an initial diagnosis of parkinsonism or uncertain tremor disorder were screened and followed-up for one year. All patients were re-examined by two neurologists at our centre and were classified as having neurodegenerative or non-neurodegenerative disorders. Patients underwent I-123 ioflupane SPECT imaging. SPECT studies were blindly evaluated and classified as normal or abnormal (indicative of neurodegenerative disorders). The overall agreement of the SPECT imaging results with the initial classification was 65.6% (kappa=0.229, p=0.074) but was 90.2% (kappa=0.782, p<0.001) with the classification of the neurologists at our centre. I-123 ioflupane SPECT imaging is a valuable method in the evaluation of patients presenting clinically with uncertain parkinsonian syndromes or for whom diagnostic doubt exists.

Brainstem auditory evoked responses that disappear during sleep: a possible manifestation of a neurogenic vestibular evoked response

OBJECTIVE

To present a case of unilateral hearing loss in which a brainstem auditory evoked potential (BAEP) disappeared during sleep on the symptomatic side, and to argue that this may actually be a manifestation of a neurogenic vestibular evoked potential (NVESTEP).

MATERIAL AND METHOD

Brainstem auditory evoked potentials were performed in the standard manner.

RESULT

A poorly organized response was obtained during wakefulness on the symptomatic side that resembled a BAEP. The BAEP for the right ear was better organized. During sleep, the response for the left ear disappeared.

CONCLUSIONS

The poor organization of the response of the left ear compared to the right, and its disappearance during sleep, suggests that the response for the left ear was actually an NVESTEP and not a BAEP. The possibility of recording vestibular responses with auditory stimuli may have important implications for BAEP examinations performed during wakefulness that may lead to false negative results, in neonatal screening for hearing loss that use tone stimuli, and also in brain mapping using magnetic resonance imaging (MRI) and positron emission tomography (PET) relating to the auditory cortex.

Vestibular symptoms and signs are correlated with abnormal neurogenic vestibular evoked potentials in patients with multiple sclerosis

OBJECTIVES

Symptoms of disequilibrium in multiple sclerosis (MS) are common. Neurogenic vestibular evoked potentials (NVsEPs) are saccular responses to tone-pip acoustic stimuli and are recordable from the parietal areas ipsilaterally to the stimulated ear. We wished to determine possible correlations of abnormal findings in NVsEP with clinical neurological findings related to the vestibular system, and demyelination seen on MRI.

PATIENTS AND METHODS

NVsEPs were performed by delivering a 1 kHz tone-pip stimulus monoaurally with contralateral masking noise via headphones. Brainstem auditory evoked potentials were performed in the standard manner.

RESULTS

Thirty-three patients had either been diagnosed with MS or had possible MS. There is statistical evidence that the presence of symptoms is likely to give an abnormal NVsEP, but no correlation exists between the presence or absence of vestibular symptoms and signs and an abnormal BAEP. No correlation was found between the presence of brainstem lesions on MRI and an abnormal NVsEP. Correlation exists between abnormal NVsEP and the level of disability using Expanded Disability Status Scale scores.

CONCLUSION

We have found that with increasing involvement of abnormal NVsEPs, there is a significant correlation with symptoms and signs that can be referred to the vestibular system.

Neurogenic vestibular evoked potentials in three cases of vestibular system dysfunction

OBJECTIVES

To demonstrate that neurogenic vestibular evoked potentials (NVsEP) may be specific to the vestibular system using three cases of vestibular system dysfunction and normal auditory function,

METHODS

Neurogenic vestibular evoked potentials were performed by recording from the parietal areas of the scalp using a tone-pip auditory stimulus via headphones. Brainstem auditory evoked potentials (BAEPs) and NVsEP were performed in all three cases.

RESULTS

Brainstem auditory evoked potentials were within normal limits in all three cases. All three patients showed abnormalities in their NVsEP In the third case, the responses normalized after treatment.

CONCLUSIONS

The findings support further the hypothesis that NVsEP are specific to the vestibular system and are a separate response from the BAEP SIGNIFICANCE: Neurogenic vestibular evoked potentials is an easy examination to carry out and can be performed in any clinical neurophysiological laboratory that is familiar with BAEPs. Examinations used to diagnose vestibular system disorders at present include the glycerol dehydration test, electrocochleography, myogenic vestibular evoked potentials and electronystagmography. Neurogenic vestibular evoked potentials may also prove to be useful.

Phenytoin-induced lymphocytic chemotaxis, angiogenesis and accelerated healing of decubitus ulcer in a patient with stroke

We studied the effect of topically applied phenytoin on the healing of a decubitus ulcer in the sacral region of an immobile patient with stroke. Another similar, but smaller, ulcer was treated with conventional treatment only and served as a control. The ulcers were measured once a week and biopsies were taken from the margins before, 1 week and 2 weeks after commencing treatment with phenytoin. Clinically, phenytoin substantially accelerated the rate of healing. Microscopic examination of the biopsies showed increased lymphocytic infiltration of the phenytoin-treated lesion. Anti-CD31 immunohistochemistry revealed dense CD31+ lymphocytic infiltration and increased angiogenesis only in the phenytoin-treated lesion. Our findings suggest that phenytoin enhances wound healing by stimulating lymphocytic chemotaxis and up-regulation of angiogenesis.

Neurogenic vestibular evoked potentials in the diagnosis of multiple sclerosis

OBJECTIVES

To determine the value of neurogenic vesibular evoked potential (NVESTEP) studies in comparison with other paraclinical tests in demonstrating dissemination in time and space in Multiple Sclerosis (MS) and in identifying clinically silent lesions.

METHOD

All patients in whom MS was suspected but the diagnosis of MS was not possible based on the McDonald criteria were included in this study. We studied 14 patients and performed visual, brainstem auditory, somatosensory and neurogenic vestibular evoked potentials in all patients, together with MRI and CSF analysis of oligoclonal bands (OB).

RESULTS

Two out of the thirteen patients could be movedfrom the category of "possible MS" to "MS" using the McDonald criteria based on an abnormal NVESTEP result.

CONCLUSION

Neurogenic vestibular evoked potentials are potentially useful in identifying clinically silent lesions in patients with possible MS.

Neurogenic vestibular evoked potentials using a tone pip auditory stimulus

OBJECTIVES

To obtain neurogenic vestibular evoked potentials (NVESTEPs) with surface scalp recording using a tone pip auditory stimulus.

METHODS

Fourteen neurologically normal volunteers (Age range 26-45 years, 10 females and 4 males), and two patients with sensorineural hearing loss and possible multiple sclerosis respectively, were examined. Two channel recordings were obtained, the first channel being P3 referred to Fpz, and the second channel being P4 referred to Fpz. A 1 kHz tone pip stimulus with two cycles was delivered via headphones monoaurally with contralateral masking noise.

RESULTS

A consistent negative wave with a mean absolute latency of 4.72 msec was obtained, which we have named N5. 25% of the ears tested had better responses at the ipsilateral parietal electrode. In the patient with bilateral sensorineural hearing loss, NVESTEPs was present, suggesting that the NVESTEP is not a cochlear response. In the patient with possible multiple sclerosis, an abnormal NVESTEP response and a normal BAEP response were found.

CONCLUSION

Use of a tone-pip rather than a click auditory stimulus allows a lower click intensity to be used in the production of NVESTEP responses, leads to a shorter testing time, and is therefore more comfortable for the patient. This study adds to our impression that the NVESTEP may be a physiological response that can be used to assess the vestibular system and is different from the BAEP response. Further testing in patients with symptoms of dizziness and with disorders specific for the vestibular nerve is required.

Click evoked neurogenic vestibular potentials (NVESTEPs): a method of assessing the function of the vestibular system

OBJECTIVES

To obtain neurogenic vestibular evoked potentials (NVESTEPs) with surface scalp recording using high intensity auditory clicks. The same stimulus is used in myogenic vestibular evoked potentials which has been shown to evoke potentials in the vestibular division of the vestibulocochlear nerve.

METHODS

A whole head recording with surface EEG electrodes was performed using high intensity clicks in one normal volunteer to determine the best recording position for vestibular evoked potentials. The results were compared to responses at moderate click intensities used for brainstem auditory evoked potentials (BAEPs). The difference in the location of the two responses on the scalp was assumed to be from the vestibular system.

RESULTS

Responses specific to the high intensity clicks were best obtained in the parietal areas, with no reproducible responses obtained in the same area with moderate intensity clicks normally used in BAEPs. Recordings in neurologically normal volunteers showed a consistent response with a negative polarity at around 3 ms, which we therefore called N3. Two case studies are presented. The first case is a patient with unilateral sensorineural hearing loss with NVESTEPs present, suggesting that NVESTEPs is not a cochlear response. The second case is a patient with multiple sclerosis with demyelinating lesions in the pons and an unobtainable NVESTEP response.

CONCLUSION

NVESTEPs is a possible new diagnostic technique that may be specific for the vestibular pathway. It has potential use in patients with symptoms of dizziness, subclinical symptoms in multiple sclerosis, and in disorders specific for the vestibular nerve.