"Effect of transcranial magnetic stimulation to motor cortex on pain perception and nociceptive reflex".

"Noxious stimulation over the foot can evoke a nociceptive flexor reflex (NR) in the lower limb especially for tibialis anterior muscle (TA). Components of NR include the monosynaptic fast latency NRII, and the polysynaptic slow latency NRIII, supposedly a spinal segmental reflex influenced by the supraspinal control. Pain perception is quantified by visual analogous scale (VAS) and has been reported to be related to NRIII. Previous papers have reported the long lasting effect of transcranial magnetic stimulation (TMS), as well as TMS suppressing pain perception. The purpose of this study was to investigate the immediate and prolonged effect of a single-pulse TMS to suppress NR and pain. NRIII was provoked at right TA by a train of electrical stimulation on the right toe in 10 healthy subjects. TMS was delivered over the vertex area to evoke right anterior tibialis muscle activity. A sham TMS from different directions of the coil was performed on the next day. The NRIII amplitude and VAS were measured. As a result, the amplitude of NRIII was significantly decreased than the control 50 ms pre-stimulation (0.20 ± 0.13 mA vs . 0.65 ± 0.42 mV, P = 0.016), 100 ms pre-stimulation (0.10 ± 0.10 mA vs . 0.65 ± 0.42 mV, P = 0.001), 15 min post-stimulation (0.12 ± 0.09 mA vs . 0.65 ± 0.42 mV, P = 0.004), and 30 min post-stimulation (0.41 ± 0.21 mA vs . 0.65 ± 0.42 mV, P = 0.046). VAS was diminished compared with the control 50 ms pre-stimulation (3.3 ± 0.9 vs . 5.4 ± 1.3, P = 0.002), 100 ms pre-stimulation (2.6 ± 0.5 vs . 5.4 ± 1.3, P < 0.001) and 15 min post-stimulation (3.5 ± 0.9 vs . 5.4 ± 1.3, P = 0.046). The NRIII amplitude was well correlated with VAS in reduction during the TMS condition and 15 min after electrical stimulation (P < 0.001). The sham TMS did not suppress NRIII or VAS. In conclusion, our results indicate that NRIII and the nociception can be inhibited by one single pulse TMS and such an effect can last for a period of time."

[Treatment guidelines for acute and preventive treatment of cluster headache].

The Treatment Guideline Subcommittee of the Taiwan Headache Society evaluated both the acute and the preventive treatments for cluster headache now being used in Taiwan, based on the principles of evidence- based medicine. We assessed the quality of clinical trials and levels of evidence, and referred to other treatment guidelines proposed by other countries. Throughout several panel discussions, we merged opinions from the subcommittee members and proposed a consensus on the major roles, recommended levels, clinical efficacy, adverse events and cautions of clinical practice regarding acute and preventive treatments of cluster headache. The majority of Taiwanese patients have episodic cluster headaches, because chronic clusters are very rare. Cluster headache is characterized by severe and excruciating pain which develops within a short time and is associated with ipsilateral autonomic symptoms. Therefore, emergency treatment for a cluster headache attack is extremely important. Within the group of acute medications currently available in Taiwan, the subcommittee determined that high-flow oxygen inhalation has the best evidence of effectiveness, followed by intranasal triptans. Both are recommended as first-line medical treatments for acute attacks. Oral triptans were determined to be second-line medications. For transitional prophylaxis, oral corticosteroids are recommended as the first-line medication, and ergotamine as the second-line choice. As for maintenance prophylaxis, verapamil has the best evidence and is recommended as the first-line medication. Lithium, melatonin, valproic acid, topiramate and gabapentin are suggested as the second-line preventive medications. Surgical interventions, including occipital nerve stimulation, deep brain stimulation, radiofrequency block of the sphenopalatine ganglion, percutaneous radiofrequency rhizotomy and trigeminal nerve section, are invasive and their long-term efficacy and adverse events are still not clear in Taiwanese patients; therefore, they are not recommended currently by the subcommittee. The transitional and maintenance prophylactic medications can be used together to attain treatment efficacy. Once the maintenance prophylaxis achieves efficacy, the transitional prophylactic medications can be tapered gradually. We suggest the corticosteroids be used within two weeks, if possible. The duration of maintenance treatment depends on the individual patient's clinical condition, and the medications can be tapered off when the cluster period is over.

Differential cerebral reactivity to shortest and longer tones: neuromagnetic and behavioral evidence.

Detecting a change in sound duration is important in language processing. The cerebral reactivity to a duration deviant in oddball paradigm has been reflected as a mismatch negativity (MMN). This study aimed to see cerebral responses to several duration-varying sounds presented with equal probability. Magnetoencephalographic (MEG) and behavior responses to equi-probable sounds (25-50-75-100-125 ms or 50-75-100-125-150 ms tones) were recorded in 10 healthy adult volunteers. By subtracting the average of the responses to 4 longer tones from the response to the shortest tone, a clear deflection peaking at 100-200 ms from stimulus onset was identified. This activity was called as sub-standard MMNm, and its amplitude tended to increase with the increment of duration deviance within a stimulation paradigm. The source of sub-standard MMNm was localized in superior temporal area, with 5-6 mm more anterior to the generator of N100m response. Behavioral tests also showed best performance in the recognition of the shortest tone than longer tones. In conclusion, the preferential response to the shortest tone in an equiprobable paradigm suggests an asymmetrical processing in the auditory cortex for duration-varying sounds.

Memory-based mismatch response to changes in duration of auditory stimuli: an MEG study.

OBJECTIVE: Differences in physical features and occurrence probability between standards and deviants in oddball paradigms provide contributions to magnetic mismatch negativity (MMNm). We aimed to reduce these influential factors and extract memory-based MMNm by adding a control paradigm. METHODS: Magnetoencephalographic responses were recorded in 13 healthy adults with an oddball paradigm (125-ms standard and 50-ms deviant tones) and an equiprobable control paradigm (50-ms control and four other duration-varying tones). The stimulus onset asynchrony was 500 ms. Controlled MMNm was obtained by subtracting control-evoked responses from deviant-evoked responses. RESULTS: With respect to the onset of stimulus difference, the peak latency of controlled MMNm was compatible with previous intracranial MMN recordings. Both controlled and traditional MMNm were generated around the superior temporal cortex, whereas the controlled MMNm amplitude was about 70% of traditional MMNm amplitude. Right-hemispheric dominance was observed in traditional MMNm but not in controlled MMNm. N100m amplitude was smaller in standard-evoked than in deviant- or control-evoked responses. CONCLUSIONS: Controlled MMNm reflects memory-based processing of duration changes, whereas traditional MMNm additionally involves non-memory activations related to differential refractoriness states and physical properties between standard and deviant stimuli. SIGNIFICANCE: The memory-based processing of auditory deviants may be preferentially extracted by adding a control paradigm.

Theta oscillation during auditory change detection: An MEG study.

To study the phase and power characteristics of brain oscillations during the preattentive detection of auditory deviance, we recorded magnetoencephalographic responses in 10 healthy subjects with an oddball paradigm. As the subject was watching a silent movie, standard tones (1000-Hz frequency, 100-ms duration) and their duration deviants (50-ms duration, probability of 15%) were randomly delivered binaurally. In addition to localizing the magnetic counterpart of mismatch negativity (MMNm) with equivalent current dipole modeling, we also measured the phase-locking value (PLV) and power change of the oscillatory responses to standard and deviant stimuli by employing the Morlet wavelet-based analysis. The MMNm signals peaking at 150-200ms after the onset of deviant were localized in bilateral temporal regions with larger amplitudes in the right hemisphere. Then 50ms after the onset of either standard or deviant stimuli, we observed an increase of PLV and power of theta and alpha oscillations in bilateral temporal regions. PLVs of theta and alpha activities to deviant stimuli were significantly larger in the right than left hemisphere (P<0.001). Compared with standard stimuli, deviants elicited a larger theta PLV (P<0.001) at 150-300ms and a larger theta power change (P<0.05) at 50-300ms for the responses in the right temporal region. In addition, a prominent theta phase-locking of deviant-elicited responses was found in the right frontal area at 110-250ms (P<0.01). Our current data suggest that a pronounced phase and power modulation on sound-elicited theta oscillations might characterize the change detection processing in the temporo-frontal network as reflected by the mismatch negativity.

Accelerated hippocampal atrophy rates in stable and progressive amnestic mild cognitive impairment.

Studies suggest that smaller hippocampal volume predicts Alzheimer's disease (AD) in mild cognitive impairment (MCI). However, few studies have demonstrated decline rates in cognition and hippocampal volume in MCI subjects with stable clinical presentation. Furthermore, the effects of apolipoprotein E (ApoE) on the change rates of medial temporal structures and cognition in MCI are rarely investigated. Fifty-eight subjects with amnestic MCI and 20 normal aging elderly controls received annual neuropsychological and magnetic resonance imaging (MRI) assessments. Annual decline rates in neuropsychological test scores, hippocampal and amygdalar volumes were calculated. ApoE genotypes were examined. Nineteen (32.7%) MCI subjects converted to AD during an average 22.5-month follow-up period. The annual hippocampal atrophy rate was correlated with a decline in memory test scores. The presence of the ApoE varepsilon4 allele did not affect the change rates in neuropsychological test scores and medial temporal structures volume. Compared to subjects with stable MCI (MCI-S) and normal aging, progressive MCI (MCI-P) had the highest annual decline rates in cognition and hippocampal volume. Logistic regression analysis showed that higher annual decline rates in hippocampal volume and global cognitive test scores were associated with conversion to AD. Furthermore, although MCI-S subjects had little cognitive decline, their hippocampal atrophy rates were higher than those of normal aging controls. Therefore, accelerated hippocampal atrophy rates may be an early and important presentation in MCI subjects.

Diagnosis and development of screening items for migraine in neurological practice in Taiwan.

BACKGROUND/PURPOSE: The objectives of this study were to: (1) survey migraine diagnoses among neurological outpatients in Taiwan; (2) compare neurologists' migraine diagnoses with the International Classification of Headache Disorders 2nd Edition (ICHD-2) criteria; and (3) evaluate the diagnostic ability of screening items on a patient migraine questionnaire. METHODS: This prospective study surveyed patients who consulted neurologists for the first time with a chief complaint of headache, excluding those experiencing headaches for > or = 15 days/month. Each neurologist interviewed a maximum of 10 patients. Patients were asked to complete a self-administered questionnaire and their physicians completed another questionnaire. The physicians were asked if patients could be diagnosed with migraine. In addition, a diagnosis of ICHD-2 migraine was made by the physician's questionnaire through a computer-generated algorithm. In this study, migraine without aura (code 1.1) or migraine with aura (code 1.2) were designated as "strict migraine", and the combination of strict migraine and ICHD-2 probable migraine (code 1.6) as "any migraine". RESULTS: Among 755 patients who were eligible for analysis, 537 (71%) were diagnosed as having "any migraine", 363 (48%) with "strict migraine", and 451 (60%) with physician-diagnosed migraine. Among the 537 patients diagnosed as having "any migraine", 308 patients (57%) had not been diagnosed by any physician before. A moderate agreement (kappa statistic around 0.5) was found between the physicians' diagnoses and ICHD-2 "strict migraine" or "any migraine". In patients with ICHD-2 probable migraine (n = 174), only 52% were diagnosed with migraine by our physicians. Nausea was the best single item for predicting migraine diagnosis, while any combination of two items among nausea/vomiting, moderate or severe pain and photophobia, provided the optimum screening tool. CONCLUSION: Migraine was the most common headache diagnosis in the neurologists' clinics. Probable migraine was not completely adopted as a migraine spectrum among neurologists. In contrast to ID Migraine(TM), moderate or severe headache intensity replaced headache-related disability as one screening item for migraine in Taiwan.

Gabapentin for decerebrate rigidity: a case report.

A 48-year-old woman suddenly lost consciousness as a result of a right rostral pontine tegmentum haemorrhage. The patient presented with decerebrate rigidity (DR) and regained full consciousness 5 days after the initial onset. The patient was given gabapentin 1200 mg/day nasogastrically and her DR significantly improved, although other antiepileptic drugs such as phenytoin and carbamazepine were given in larger dosages to decrease muscle hypertonicity. The patients' preserved consciousness and motor-evoked potentials to transcranial magnetic stimulation indicated a derangement of the extrapyramidal tracts with preservation of the pyramidal tracts. This case report discusses the possible mechanisms of action of gabapentin in DR.

Effect of sacral neuromodulation on the spinal nociceptive reflex of patients with idiopathic overactive bladder.

Objectives. Sacral root stimulation (SRS) is a technique to restore the idiopathic overactive bladder (IOB). However, its mechanism of action is yet to be elucidated. Hence, we studied whether SRS restored IOB through the mechanism of spinal neuromodulation. Materials and Methods. Six IOB patients and 10 healthy volunteers were included in the study. The spinal nociceptive reflex was used as the index of spinal excitability and was evoked by electrical stimulation at the foot, with recording at the ipsilateral tibialis anterior. Results. IOB patients had increased spinal excitability to somatic nociceptive stimuli of the lower limbs. This spinal excitability decreased and bladder function improved after SRS, an effect that outlasted actual stimulation by at least 30 min. Conclusions. Our results showed that spinal excitability was increased in response to somatic nociceptive afferents in IOB patients. SRS restored bladder function, at least, in part, through spinal neuromodulation.

Oscillatory characteristics of nociceptive responses in the SII cortex.

OBJECTIVE: This study is aimed to explore the frequency characteristics of pain-evoked neuromagnetic responses in the secondary somatosensory (SII) cortices. METHODS: Thulium-laser nociceptive stimuli to the left hand dorsum of 10 right-handed healthy adults. The pain stimuli were rated as mild, moderate, and severe levels according to subjects' reports on a 10-point visual analog scale. We analyzed their cortical responses with wavelet-based frequency analyses and equivalent current dipole (ECD) modeling. RESULTS: For each pain level, we found an increase of theta (4-8 Hz) and alpha (8-13 Hz) power in bilateral SII areas at 180-210 ms after stimulus onset. The power was larger for the moderate than for the mild pain level (p < 0.05), but there was no statistical power difference of these oscillations between moderate and severe pain stimulus conditions (p = 0.7). Within the SII area, we did not observe particular difference in theta and alpha ECD locations between varying pain level conditions. CONCLUSIONS: The 4-13 Hz activities, peaking from 180 to 210 ms, are oscillatory correlates of SII activation in response to nociceptive stimulation, but their power may code the magnitude of pain stimuli only up to moderate level, as rated subjectively. This measure could be potentially used to evaluate SII activation in further pain studies.

Multimodal evoked potentials of Kennedy's disease.

BACKGROUND: Kennedy's disease (KD) is an X-linked recessive polyglutamine disease. Traditionally, it is a lower motor neuron syndrome with additional features such as gynecomastia and tremor. Sensory symptoms are minimal if ever present. We used multimodal evoked potential (EPs) tests to study the distribution of the involvement of the disease. METHODS: Visual, brainstem auditory, somatosensory and motor EPs were studied in six KD patients. All of them had typical presentations and had been proved genetically. RESULTS: Abnormal findings were noted as follows: prolonged peak latencies of visual EPs, increased hearing threshold level, inconsistent brainstem auditory EPs, decreased amplitudes of cortical potentials of somatosensory EPs, and increased motor threshold to transcranial magnetic stimulation. CONCLUSIONS: Our multimodal EP studies showed that KD involved multiple levels of the nervous system. It implies the widespread effects of the mutant androgen receptors.

Brainstem excitability is increased in subjects with palmomental reflex.

BACKGROUND/PURPOSE: The palmomental reflex (PMR) is a brief contraction of the mentalis muscles caused by a scratch over the thenar eminence, i.e. a brainstem reflex to afferents of upper limb. Using electrophysiologic methods, we studied the characteristics of brainstem excitability in PMR subjects. METHODS: Ten healthy PMR subjects were included in the study. Brainstem excitability was assessed with electrical stimulation at the trigeminal nerve, median nerve, ulnar nerve, and sural nerve with recordings at the mentalis muscles. A comparison was made by the probability between the mechanical scratch and the electrical stimulation to evoke the visible muscle contraction of mentalis. RESULTS: An electrical stimulus was able to elicit mentalis muscle responses (MMR(electrical)) in all the subjects if the stimulus was of sufficient strength. Using electrical stimulation, the median nerve at the wrist was the best site to evoke MMR(electrical). However, in PMR subjects, the probability of MMR(electrical) to median nerve stimulation was less than that of MMR(scratch), i.e. the clinical findings of PMR. Significantly lower thresholds and higher amplitudes were noted in PMR subjects only when the median nerve was stimulated. The onset latency did not show any difference between the two groups despite the stimulation sites. CONCLUSION: The facial motor neurons to median nerve stimulation are more sensitive in PMR subjects. In healthy PMR subjects, this indicates that the excitability increases only in the specific neuronal circuits between the lower cervical spinal cord and the facial motor nucleus in the rostral medulla. MMR(electrical) is a physiologic phenomenon, and PMR is a sign of increased brainstem excitability.

Side of the stimulated ear influences the hemispheric balance in coding tonal stimuli.

OBJECTIVE: To evaluate whether the side of stimulated ear affects the hemispheric asymmetry of auditory evoked cortical activations. METHODS: Using a whole-head neuromagnetometer, we recorded neuromagnetic approximately 100 ms responses (N100m) in 21 healthy right-handers to 100 ms 1 kHz tones delivered alternatively to left and right ear. RESULTS: Although the peak latencies of N100m were shorter in contralateral than in ipsilateral hemisphere, the difference was significant only for the left ear stimulation. Based on the relative N100m amplitudes across hemispheres, the laterality evaluation showed a rightward predominance of N100m activation to tone stimuli, but the lateralization toward the right hemisphere was more apparent by the left than by the right ear stimulation (laterality index: -0.27 versus -0.10, p=0.008). Within the right hemisphere, the N100m was 2-4 mm more posterior for left ear than for right ear stimulation. CONCLUSIONS: The hemispheric asymmetry in auditory processing depends on the side of the stimulated ear. The more anterior localization of right N100m responses to ipsilateral than to contralateral ear stimulation suggests that there might be differential neuronal populations in the right hemisphere for processing spatially different auditory inputs.

Neurotoxicity of nitrous oxide: multimodal evoked potentials in an abuser.

INTRODUCTION: Nitrous oxide (N2O) damages the nervous system of chronic abusers. Multimodal evoked potentials (EPs) can help document the electrophysiological abnormalities of N2O abusers and its distribution in the nervous system. CASE REPORT: A 41-year-old male N2O abuser had used N2O (4-5 cans/per day, about 2000 ml/can) for more than 10 years. He complained of progressive motor clumsiness and distal paresthesia in the four limbs. Abnormal laboratory tests were megaloblastic red blood cells (102.3 fL, normal 80-94 fL) and serum vitamin B12 concentration of 143 pg/nL (normal 160-970 pg/nL). An MR image did not show significant findings in the brain but demonstrated conspicuous changes in the posterior and lateral columns at the C2-C7 level, in accordance with the anatomical lesions of the subacute combined degeneration of the spinal cord. In addition to sensori-motor axonal polyneuropathy, multimodal EPs showed abnormal visual EPs with prolonged peak latencies of P100, abnormal brainstem auditory EPs characterized by delayed wave V and difficulty in the recognition of waves I and III, abnormal somatosensory EPs with significant decreased peak amplitudes of cortical potentials bilaterally, and abnormal motor EPs to transcranial magnetic stimulation with prolonged central motor conduction time. CONCLUSION: Our studies document electrophysiological abnormalities that may be attributed to N2O and indicate that N2O may indirectly involve multiple levels of the nervous system.

Intranasal sumatriptan study with high placebo response in Taiwanese patients with migraine.

BACKGROUND: Triptan's efficacy in the treatment of migraine has never been reported in Taiwanese. A high placebo effect was reported in Japanese. The objective of this study was to evaluate the efficacy of intranasal sumatriptan in the acute treatment of migraine in Taiwanese patients. METHODS: Fifty-eight patients who had experienced migraine for at least 1 year were randomly assigned to 2 groups, self-administered intranasal sumatriptan 20 mg or placebo to treat a single migraine attack of moderate or severe intensity. RESULTS: A significant difference in headache relief rates between the 2 groups was observed at 30 minutes postdose (46% vs. 21%, p < 0.05). One hour postdose, 61% of sumatriptan recipients experienced headache relief compared with 43% of placebo recipients (p = 0.181). The difference in relief rates between groups diminished over time, mainly due to a high placebo response (54% at 2 hours postdose). CONCLUSION: Our study suggests that ethnicity might have a role in placebo response, and highlights the importance of a placebo group in acute migraine trials. However, the small sample size in this study should also be taken into consideration.

Plastic phase-locking and magnetic mismatch response to auditory deviants in temporal lobe epilepsy.

The magnetic equivalent (MMNm) of mismatch negativity may reflect auditory discrimination and sensory memory. To study whether temporal lobe epilepsy (TLE) affects automatic central auditory-change processing, we recorded magnetoencephalographic (MEG) responses to standard and duration-deviant sounds in 12 TLE patients and 12 age-matched controls, and repeated MEG measurement in 8 patients 6-30 months following epilepsy surgery and in 6 controls 3-8 months after their first measurement. We compared the MMNm between patients and controls, and also evaluated intertrial phase coherences as indexed by phase-locking factors (PLF) using wavelet-based analyses. We observed longer MMNm latencies for patients than for controls. Dipole modeling and minimum-current estimates together showed bi-frontotemporal sources for MMNm. The phase locking across trials was dominant at the 4- to 14-Hz band, and the main difference in PLF between deviant- and standard-evoked responses occurred in the time frame of 150-250 ms after stimulus onset. Notably, in the 5 patients who became seizure free after removal of right temporal epileptic focus, the phase-locking phenomena resulting from deviant stimuli were enhanced, and even more distributed in the frontotemporal regions. We conclude that mesial TLE might affect auditory-change detection, and a successful surgery causes a possible plastic change in phase locking of deviant-evoked signals.

Transcranial magnetic stimulation after conditioning stimulation in two adrenomyeloneuropathy patients: delayed but facilitated motor-evoked potentials.

Two male patients were diagnosed with adrenomyeloneuropathy. Their chief problems were progressive spastic paraparesis, sensory impairment, hyperpigmentation and testis atrophy. Transcranial magnetic stimulation (TMS) does not easily elicit motor-evoked potentials (MEPs) in patients with a central nervous system dysfunction, even though a few methods, such as contraction of the target muscles and the Jendrassik maneuver (JM), are used in the attempt to facilitate them. In these two patients, we used a conditioning method (prior electrical stimulation over the cutaneous nerve of the left index finger) in order to facilitate MEPs, elicited by TMS, in the left tibialis anterior muscle. In patient 1, facilitation of MEPs was present at conditioning-test (C-T) intervals in the range 60-220 ms, with the maximal MEP recorded at C-T 160 ms; in patient 2, it occurred in the C-T interval range 110-140 ms, with the maximal MEP recorded at C-T 130 ms. By means of conditioning electrical stimulation, we can facilitate MEPs elicited by TMS in those subjects in whom MEPs are minimal or difficult to elicit even using the conventional JM or muscle contraction. The facilitation of MEPs by conditioning stimuli allowed us not only to assess central motor conduction time, but also to demonstrate the preserved continuity of the corticospinal tract in these two patients.

Mentalis muscle responses to median nerve stimulation.

Electrical stimulation may produce excitation or inhibition of the motor neurons, as represented the blink reflex and masseter silent period in response to trigeminal nerve stimulation. Clinically, a light touch on the palm may evoke a mentalis muscle response (MMR), i.e. a palmomental reflex. In this study, we attempted to characterize the MMR to median nerve stimulation. Electrical stimulation was applied at the median nerve with recordings at the mentalis muscles. An inhibition study was done with continuous stimuli during muscle contraction (I1 and I2 of MMRaverage). Excitation was done with a single shot during muscle relaxation (MMRsingle) or by continuous stimuli during muscle contraction (E1 and E2 of MMRaverage). The characteristic differences between MMRaverage and MMRsingle were as follows: earlier onset latencies of MMRaverage (MMRaverage < 45 ms; MMRsingle > 60 ms), and a lower amplitude of MMRaverage (MMRaverage < 50 microV; MMRsingle > 150 microV). The receptive field of MMRsingle was widespread over the body surface and that of MMRaverage was limited to the trigeminal, median and index digital nerves. Series of stimuli usually significantly decreased the amplitude of MMRsingle, as a phenomenon of habituation. On the other hand, it was difficult to evoke the earlier response (i.e. MMRaverage) without continuous stimuli and an average technique. MMRaverage had the components of both excitation (E) and inhibition (I); for example, E1-I1-E2-I2 or I1-E2-I2. E2 was the most consistent component. In patients with dorsal column dysfunction, median nerve stimulation could successfully elicit MMRsingle, but not MMRaverage. Contrarily, in patients with pain sensory loss, it was more difficult to reproduce MMRsingle than MMRaverage. It seemed that MMRaverage and MMRsingle did not have equivalents across the different modalities of stimulation.

Hydrocephalus associated with Guillain-Barre syndrome.

A 68-year-old man developed progressive four-limb weakness and areflexia 17 days after an influenza vaccination. He was diagnosed with Guillain-Barre syndrome (GBS), and remained ventilator dependent and bed-bound for 3 months, despite plasmapheresis and immunoglobulin infusion. However, cognitive impairment, excessive daytime sleepiness, and motor disability were still present, even when he was no longer ventilator dependent. Brain computerized tomography scan and isotope cisternography was consistent with normal pressure hydrocephalus. His motor control and cognitive function recovered almost completely after insertion of a ventriculoperitoneal shunt. Although hydrocephalus is not frequently associated with GBS, our case report indicates that brain imaging is necessary in GBS patients whose cognitive functions deteriorates after disease onset.