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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.

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.

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(subscript 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(subscript electrical). However, in PMR subjects, the probability of MMR(subscript electrical) to median nerve stimulation was less than that of MMR(subscript 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(subscript electrical) is a physiologic phenomenon, and PMR is a sign of increased brainstem excitability.

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. [J Chin Med Assoc 2007;70(2):39–46]

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.

To elucidate the role of somatosensory cortices in coding pain magnitude, we recorded the neuromagnetic responses of ten subjects to mild, moderate, and severe pain stimulation by delivering thulium-laser pulses on the dorsum of the left hand. The stimulus intensities for producing different pain levels were determined individually, and the mean values across subjects were 255, 365, and 490 mJ for mild, moderate, and severe pain, respectively. We obtained 40 responses for each intensity condition, and analyzed the averaged cortical signals by multi-dipole modeling. All subjects showed consistent activation over the bilateral secondary somatosensory (SII) cortices for each intensity level, peaking around 150–230 ms, with 15-ms earlier on the contralateral hemisphere. The SII dipole strength was significantly larger for the moderate than for the mild pain stimulation, but lacked further increase as the pain magnitude elevated to the severe level. In contrast, the primary somatosensory cortical response was detected in only half of our subjects, and thus it seemed difficult to evaluate its role in pain intensity coding. Our results suggest that activation strength in human SII cortices reflects the magnitude of peripheral noxious inputs only up to the moderate level, and some other cerebral correlates may get involved in sensing a further increment of pain magnitude.

Objective:To determine the impact of check size and interstimulus interval (ISI) on neuromagnetic visual cortical responses.Methods:We recorded visual evoked fields to pattern-reversal stimulation with central occlusion in ten subjects. The ~100 ms magnetic activation (P100m) was analyzed by single dipole modeling.Results:With 1 s ISI, P100m strengths increased as check size increased from 15' up to 120' of visual arc, and larger checks elicited less P100m activation. With 120' checks, we found no P100m attenuation as ISI decreased from 4 s to 0.16 s. P100m sources around the calcarine sulcus did not vary with check size or ISI.Conclusions:The magnitude of cortical activation during visual contrast processing is check size-dependent and the 120' checks are optimum for future studies on neuromagnetic visual cortical functions using central-occluded stimulation. The corresponding neuronal activation demonstrated a short refractory period less than 0.16 s. We also found significantly overlapping cortical representation areas for different check sizes or ISIs.

Myelin protein zero gene (MPZ) mutations may account for a small proportion of cases of Charcot-Marie-Tooth disease (CMT). Different MPZ mutations may be associated with different clinical and electrophysiological phenotypes. To expand our understanding of the characteristics of nerve conduction velocity (NCV) in patients with different MPZ mutations, the authors collected and analysed the NCV values from patients with MPZ mutations. The NCVs of fourteen patients from six families carrying MPZ mutations of Val58Asp, Ser63Phe, Thr65Ile,Arg98Cys, Arg98His, and Ser233fs were collected retrospectively. Five of them had received nerve conduction studies (NCS) twice. The mutations were verified by polymerase chain reaction (PCR) amplifications and nucleotide sequencing. Scatterplot analyses of median motor NCV (MNCV) versus specific MPZ mutation were performed. The median MNCV varied widely, with a mean of 16.3 m/s (SD=7.7 m/s) and a range of 5.1–32.9 m/s. Median MNCVs of patients with particular MPZ mutations were similar. Moreover, Median MNCV did not change significantly over time. There was concordance between median MNCV and specific MPZ mutations. However, median MNCV is not an ideal measure with which to distinguish CMT1B patients with MPZ mutations from CMT1A patients with PMP22 mutations.

Transcranial magnetic stimulation (TMS) of the motor cortex can interrupt voluntary contralateral rhythmic limb movements. Using the method of “resetting index” (RI), our study investigated the TMS effect on different types of bimanual movements. Six normal subjects participated. For unimanual movement, each subject tapped either the right or left index finger at a comfortable rate. For bimanual movement, index fingers of both hands tapped in the same (in-phase) direction or in the opposite (antiphase) direction. TMS was applied to each hemisphere separately at various intensities from 0.5 to 1.5 times motor threshold (MT). TMS interruption of rhythm was quantified by RI. For the unimanual movements, TMS disrupted both contralateral and ipsilateral rhythmic hand movements, although the effect was much less in the ipsilateral hand. For the bimanual in-phase task, TMS could simultaneously reset the rhythmic movements of both hands, but the effect on the contralateral hand was less and the effect on the ipsilateral hand was more compared with the unimanual tasks. Similar effects were seen from right and left hemisphere stimulation. TMS had little effect on the bimanual antiphase task. The equal effect of right and left hemisphere stimulation indicates that neither motor cortex is dominant for simple bimanual in-phase movement. The smaller influence of contralateral stimulation and the greater effect of ipsilateral stimulation during bimanual in-phase movement compared with unimanual movement suggest hemispheric coupling. The antiphase movements were resistant to TMS disruption, and this suggests that control of rhythm differs in the 2 tasks. TMS produced a transient asynchrony of movements on the 2 sides, indicating that both motor cortices might be downstream of the clocking command or that the clocking is a consequence of the 2 hemispheres communicating equally with each other.

Pyruvoyl-tetrahydropterin synthase (6PTPS) deficiency is a major cause of biopterin deficiency. 6PTPS patients usually have an elevated serum phenylalanine level, a deficiency of neurotransmitters (serotonin and dopamine), and neurological symptoms, if without treatment. We herein investigated the possibility of neurological dysfunction in early-treated patients. In the study, 12 early-treated 6PTPS patients were studied. Their auditory simple reaction time, movement rhythm variation (MRV), somatosensory evoked potentials to median nerve stimulation, and hand muscle responses to transcranial magnetic stimulation, were measured. MRV is a test of repetitive voluntary movements, and was used with and without auditory cues at 0.3 Hz. The 6PTPS patients had an increased motor threshold but normal motor and sensory central conduction times. They performed very well in simple reactions (6PTPS 208.4 ^ 16.7 ms, control 200.3 ^ 11.7 ms, p ¼ 0.18), but not in continuous tasks. The continuous performance tests showed that MRV had increased in the 6PTPS patients (with cues: 6PTPS 7.35 ^ 0.94, control 5.47 ^ 0.80, p , 0.0001; without cues: 6PTPS 9.87 ^ 1.44, control 6.59 ^ 0.68, p , 0.0001). Without cues, MRV had increased in both the 6PTPS and control groups, but more significantly in the 6PTPS patients (6PTPS 2.51 ^ 0.97, control 1.25 ^ 0.42; p ¼ 0.0001). Our findings indicate that early-treated 6PTPS patients have subtle neurological dysfunctions. They may not maintain movement rhythm as well as normal subjects, even with external cues. Hence, MRV is a good method to assess motor control. q 2003 Elsevier B.V. All rights reserved.

We investigated cardiovascular autonomic functions in 23 patients with Alzheimer's disease (AD) and 23 age-matched control subjects. The vagal parasympathetic function was assessed with R-R interval variation (RRIV), and sympathetic function with sympathetic skin response (SSR) and orthostatic cardiovascular reflexes. Compared with controls, the AD patients had significantly depressed RRIV during rest (6.4 +/- 1.3% vs. 7.5 +/- 1.6%, p < 0.02) and deep breathing (12.6 +/- 4.6% vs. 17.0 +/- 5.1%, p < 0.006), but all AD patients had normal SSR. After standing for 3 minutes from supine, the changes of blood pressure and heart rate from baseline in AD patients did not differ from those in controls. The AD patients had a lower systolic blood pressure than controls in both supine (130.7 +/- 17.4 vs. 145.4 +/- 20.7 mmHg, p < 0.02) and standing (129.2 +/- 20.1 vs. 146.6 +/- 21.1 mmHg, p < 0.008) positions, especially in those patients with more severe dementia. We conclude that AD patients have mildly impaired autonomic functions, mainly in vagal parasympathetic functions. The pathogenesis and clinical significance of low blood pressure in AD needs further study.

The sympathetic skin response (SSR) was measured in 35 normal healthy adults and in 40 patients with diabetic polyneuropathy. When recording from the hand or the foot, the SSR latency was the same whether stimulating at the hand or the foot. This may suggest that the conduction velocity of afferent fibers is much faster than that of efferent fibers, so that the former do not contribute to the SSR latency. The SSR amplitudes were significantly reduced in diabetic patients (p < 0.001), but their latencies were normal as long as responses could be detected. It is possible that some surviving unmyelinated fibers and/or regenerated fibers take the responsibility for normal conduction. Another possible explanation is that the postganglionic unmyelinated fibers in polyneuropathy may represent themselves as 'all or none', i.e., either the fibers conduct with normal velocity or they do not conduct at all.

From July 1988 to June 1989, the etiology was registered of 520 patients with generalized neuropathy in 5 neurological centers in Taiwan. The neuropathy was diabetic in 256 cases (49.23%), alcoholic in 45 (8.65%), inflammatory in 34 (6.53%; including 21 with acute inflammatory demyelinating polyneuropathy, 12 with chronic inflammatory demyelinating polyneuropathy, and 1 with chronic relapsing polyneuropathy), 12 with associated malignancy (2.31%), 9 with dysproteinemia (1.73%), uremic in 22 (4.23%), hereditary motor and sensory in 22 (4.23%), toxic in 14 (2.69%), ischemic in 12 (2.31%), hypothyroidism in 10 (1.92%), nutritional deficiency and malabsorption in 6 (1.15%), chronic liver disease in 4 (0.77%), other diseases in 11 (2.12%) and unclassified in 63 (12.12%). This survey provided a crude etiological picture of generalized neuropathy on this island.

We investigated autonomic function in patients with idiopathic Parkinson's disease (PD) by measuring sympathetic skin response (SSR) and R-R interval variation (RRIV). Sixty-two PD patients and 62 age-matched normal subjects were recruited. Abnormal SSR was noted in nine (14.5%) PD patients, including three in Stage II, three in Stage III, and three in Stage IV, but not in Stage I patients or normal subjects. Four of these nine patients had postural hypotension. Abnormal SSR was correlated with duration of illness and impotence. In PD patients, abnormal SSR may be due to intermediolateral column dysfunction. After logarithmic transformation and age adjustment, 19 (31.6%) of 60 PD patients had abnormal RRIV during rest and deep breathing. Abnormal RRIV was not related to staging or duration of illness. Patients with constipation had significantly lower RRIV, indicating parasympathetic dysfunction. RRIV was not affected by acute or chronic L-dopa treatment. The agreement between RRIV and SSR in PD patients was poor (kappa = -0.07). It appears that abnormal SSR, but not RRIV, may be associated with more autonomic disturbances in PD patients.

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.

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.

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 ɛ4 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.

To evaluate whether the side of stimulated ear affects the hemispheric asymmetry of auditory evoked cortical activations.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.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.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.

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 (MMRaverage45 ms; MMRsingle60 ms), and a lower amplitude of MMRaverage (MMRaverage50 microV; MMRsingle150 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.

Purposes To elucidate the oscillatory dynamics with respect to interictal spike occurrence in benign rolandic epilepsy (BRE). Methods Using a whole-scalp magnetoencephalography (MEG), we recorded scalp EEG and MEG signals in 10 BRE patients (age 8–12 years) and visually identified unilateral interictal spikes that were simultaneously present on both EEG and MEG channels. We obtained the peak timing of individual spike complex based on MEG single-dipole modeling, and then applied wavelet transform to analyze the time–frequency components of corresponding MEG signals with respect to spike occurrence. Results In the hemisphere with time-domain spike waveforms, we identified a clear increase of 0.5–40Hz activity around the spike peak, most prominent at alpha band (8–13Hz). Notably, at the approximate timing we also observed an increase in 0.5–25Hz oscillations over the homotopic area in the other hemisphere where no spike signals were found. Conclusions Our results indicate bilateral increases in 0.5–25Hz oscillations during unilateral spike formation in BRE patients. By using wavelet transform analysis, one could be able to detect some irritative feature that would in visual analysis remain undetected.

To study the neural correlates of Chinese word-appropriateness judgment, we used 2-word phrases and corresponding meaningless pairs produced by replacing the second words (W2) with homophones. Fourteen right-handed healthy adults viewed word pairs randomly presented one word at a time, and judged the lexical appropriateness of the W2 for combining its preceding first word (W1) into a meaningful phrase. We measured magnetoencephalographic (MEG) responses to W1, appropriate W2, and inappropriate W2 stimuli. For each subject, multi-dipole analyses revealed sequential neuromagnetic activations which involved the bilateral visual cortices at approximately 100 milliseconds (ms), the bilateral occipitotemporal regions at approximately 190 ms, and the left temporal lobe at approximately 350 ms (M350) following stimuli. We found that the word appropriateness had no clear effect on the occipitotemporal activation to W2 stimuli, whereas the M350 activation to inappropriate W2 was greater than that to W1 or appropriate W2. In 8 of our subjects, we found an additional activation in the right temporal region, with a smaller amplitude as compared with the left M350. Our results suggest that the M350 activity reflects both lexical and semantic appropriateness assessment. The lateralized M350 strengths may be used to determine the language dominance hemisphere; and additionally, our 2-word contexture judgment paradigm can be applied in further research on the cortical processing of lexicon-semantic information in Chinese speakers.

To study the oscillatory activities during face processing, we recorded magnetoencephalographic responses in 8 healthy subjects to upright and inverted human faces, and obtained the time-frequency representation by using wavelet transform. Delta to beta activities were clearly increased at 140-210 ms after stimulus onset in the bilateral occipitotemporal (OT) areas (t(7)5.5; p0.001), with larger power for theta, alpha and beta over the right side. Notably, more increase alpha activity for inverted than upright face condition was observed in the right OT area. Our results suggest that 4-25 Hz oscillations are involved in face information processing, and the more activation over the right OT implies the right hemisphere advantage for face perception. Moreover, the alpha activity may reflect the differential cortical demands for processing inverted and upright face images.

OBJECTIVE To report a case in which significant hypotension occurred after initiation of tizanidine in a patient using the antihypertensive agent lisinopril. CASE SUMMARY A 48-year-old woman was admitted due to cerebral hemorrhage at the midbrain and pons, with extension to the fourth ventricle. Consciousness disturbance (Glasgow coma scale 4) with a decerebrate posture improved 5 days after stroke onset. As the BP was fairly high, antihypertensive agents, including lisinopril, were initiated. Three weeks later, the decerebrate rigidity and high BP remained, and tizanidine was initiated to see whether the decrease in muscle tone could facilitate hypertension control and motor recovery. However, the BP dropped dramatically within 2 hours after the first dose of tizanidine. The tizanidine and all of the antihypertensive medications were withdrawn. Tizanidine was used again after her BP had stabilized, but did not produce similar problems. DISCUSSION A similar event was reported in 2000. The reaction in our patient appeared after tizanidine initiation and improved after both lisinopril and tizanidine were discontinued. According to the Naranjo probability scale, this was classified as a possible drug interaction. This kind of reaction is seldom mentioned as occurring during co-administration with tizanidine. With its characteristics, tizanidine has the potential to compromise hemodynamic stability during concomitant angiotensin-converting enzyme inhibitor use. CONCLUSIONS Based upon the literature review, the hypotension in this patient was possibly due to the interaction between tizanidine and lisinopril.

By definition, transient ischemic attacks (TIAs) do not leave a neurological deficit beyond 24 hours after onset. However, a subgroup of TIA patients is characterized by persistent perfusion defect on single photon emission computed tomogram or infarction on brain computerized tomogram and magnetic resonance imaging. Here, we applied transcranial magnetic stimulation (TMS) to study whether TIA could produce persistent subclinical dysfunction for more than 24 hours.The study included 23 TIA patients who had the criteria of hand weakness as one of their clinical manifestations. TMS was done twice in each TIA patient. The first time was during the period of 24-48 hours after onset and the second 7 days after onset. We studied the cortical motor threshold, the latencies and the amplitudes of the motor evoked potentials, the central motor conduction time, and the cortical silent period at the intensity of 1.5 times motor threshold with maximal voluntary isometric contraction. The recording was at the first dorsal interosseous muscle.There was no significant difference between the whole group of TIA patients and normal control. However, in the subgroup of TIA patients who had hand weakness more than 1 hour, they had increased motor threshold and prolonged cortical silent period during the first test. Both improved 1 week after onset. On the contrary, in TIA patients who had hand weakness less than 1 hour, their data were all within normal limits during the first and the second studies.Our results indicate that the motor function of TMS study will recover to full if the motor symptoms subside within 1 hour in TIA patients. Subclinical motor deficits may persist in TIA patients who have motor symptoms more than 1 hour.

Hand movement constitutes the most common daily activities in our life. Hand dexterity is often impaired in patients with neurological disease. We developed an adjunct method, based upon the electrodiagnostic software, for study of motor control and hand dexterity.Thirty-two normal subjects, 2 stroke patients and 2 Parkinson patients were included in the study. All of them were right-handed, and were asked to pace rhythmic finger tapping at a comfortable rate without cue or any external stimuli. A trigger kit was designed to transform the finger tapping. After using the triggering mode and adjusting the sweep speed, 2 tapping signals were simultaneously displayed on the screen. The first signal was the triggering potential, and the variation in timing of the second signal represented the variation in timing of the inter-response interval. Twenty sweeps were recorded, superimposed and measured on the screen. Movement rhythm variation (MRV) was defined as b/a x 100 (b = [maximal interval of finger tapping - minimal interval of finger tapping]; a = [maximal interval of finger tapping + minimal interval of finger tapping]/2). Each subject started with right hand and then left hand.MRV measurement showed excellent intrarater (r = 0.97) and interrater (r = 0.97) reliability. In normal right-handed subjects, the MRV was better in right hand than in left hand (right 16.5 +/- 4.1% and left 21.0 +/- 7.6%; p0.05). The MRV improved in stroke patients along with the recovery and improved in Parkinson patients after levodopa treatment.MRV was a good method to provide quantitative data for assessment of hand dexterity. Our study also showed the potential role of MRV in motor control study.

The purpose of this study was to study the relationship between interictal spike sources and somatosensory cortices in benign rolandic epilepsy of childhood (BREC) using a whole-scalp neuromagnetometer. We recorded spontaneous magnetoencephalography (MEG) and EEG signals and cortical somatosensory-evoked magnetic fields (SEFs) to electric stimulation of the median nerve in 9 children with BREC. Interictal rolandic discharges (RDs) and SEFs were analyzed by equivalent current dipole (ECD) modeling. Based on the orientation and locations of corresponding ECDs, we compared generators of RDs with primary (SI) and second somatosensory cortices (SII). Our results showed that RDs and SII responses had similar ECD orientation on the magnetic field maps. The ECDs of RDs were localized 15.3 +/- 1.9 and 12.2 +/- 2.8 mm anterior to SI and SII, respectively. The spatial distance on average from the location of RDs to SII (21.9 +/- 1.6 mm) cortex was significantly shorter than to SI cortex (29.7 +/- 1.7 mm) (P

Background : Charcot–Marie–Tooth disease type 1 (CMT1) is the most common inherited peripheral neuropathy and represents a genetically heterogeneous condition. In addition to the peripheral myelin protein 22 gene ( PMP22 ) duplication (CMT1A), myelin protein zero gene ( MPZ ) mutations may account for a certain portion of CMT1 patients (CMT1B). Objectives : The authors analyzed the MPZ mutations in Taiwanese patients who do not have PMP22 duplication. Specifically, their clinical and molecular features were characterized. Materials and methods : Twenty-four of 57 unrelated Taiwanese patients with CMT1 were selected after excluding the CMT1A duplication. Subsequent analysis of the coding regions of the MPZ gene was performed with single-strand-conformation polymorphism (SSCP), which was then followed by nucleotide sequencing. Results : Four missense mutations and one 4-base pair (bp) deletion, respectively, were identified in five patients, of which one mutation, c.173 T>A, has never been previously reported. Three missense mutations were located in exon 2, the other one in exon 3, and the deletion in exon 6. Conclusions : This study expands the number of CMT1 associated MPZ mutation and suggests that analysis of the coding sequence of MPZ should be performed in all CMT patients without CMT1A duplication to clarify their disease nature.

It has been shown that thrombolytic therapy can improve clinical outcome in some patients with acute cerebral ischemia. These patients have been reported to be characterized by certain clinical and imaging findings, mainly with non-contrast enhanced computed tomography (CT). Our purpose in this study was to find out whether CT angiography (CTA) information about the status of the cerebral vessels is helpful in the selection of patients who may benefit the most from thrombolytic therapy for acvte cerebral ischemia. CTA was prospectively performed in 15 consecutive patients (6 women and 9 men; age range 44-83 years) with moderate or severe symptoms of hyperacute cerebral ischemia. The clinical manifestations of the patient’s condition and the findings on CTA were analyzed. Three-dimensionally reconstructed CTA images of diagnostic quality could be obtained for all 15 patients. Of the 15 patients 14 had a vessel occlusion identified on CTA, which was consistent with and/or helpful for making the clinical diagnosis in all 14 cases; one patient had an aneurysm of the anterior communicating artery without detectable hemorrhage on CTA. Although a thrombolytic agent was not given because of CTA evidence of intracranial aneurysm, the patient nevertheless developed a massive subarachnoid hemorrhage during hospitalization. Ischemic symptoms reversed after CTA and before the initiation of thrombolytic therapy in 2 patients whose CTAs showed occlusion of secondary branch of the middle cerebral artery (MCA). CTA can provide important information before the initiation of thrombolytic therapy. Identification both of the occluded vessel and of an intracranial aneurysm is feasible with the use of CTA, which is particularly important if the intracranial aneurysm is a potential contraindication to thrombolytic therapy. Occlusion of a secondary branch of the MCA and internal carotid artery occlusion are valuable prognostic predictors.

Objective : Spinocerebellar ataxia type 6 (SCA6) is a neurodegenerative disorder characterized by a slowly progressive ataxia and dysarthria. Anatomically, SCA6 was said to affect only the cerebellum. However, it has been argued that SCA6 may involve widespread regions of the brain. This study was designed to investigate the electrophysiological functions of the central nervous system in patients affected with SCA6. Methods : Nine patients with SCA6 and 10 normal, age-matched control subjects were included in the study. The motor evoked potentials, somatosensory evoked potentials, and long latency reflex (LLR) of the hand muscle were measured to evaluate the functions of the central nervous system. Results : Significantly delayed LLR, as well as prolonged cortical relay time (CRT) and central motor conduction time (CMCT) of the hand muscle, were noted in the patients with SCA6. Conclusions : The prolongation of CMCT and CRT suggested that SCA6 disturbed the functions of the corticospinal tract and the transcortical polysynaptic pathways from the sensory to motor cortices. It seems likely that the CNS dysfunction caused by SCA6 is not limited to the structures that are anatomically abnormal. Furthermore, the prolongation of CMCT alone does not seem to suffice to differentiate between various types of autosomal dominant cerebellar ataxias. Molecular analysis is indispensable for the diagnosis of different genetic types of SCA.

A 68-year-old woman and a 72-year-old man presented with distal weakness of the limbs and numbness following an influenza vaccination within 2 weeks. Moreover, Guillain-Barre syndrome (GBS) was diagnosed in two patients. Pericarditis was diagnosed in the first patient who also had precordial chest pain with referral to trapezius ridge, and nephrotic syndrome, was observed in the second patient who had leg edema and proteinuria. The relationship among GBS, pericarditis and nephrotic syndrome after an influenza vaccination is discussed.

Summary We investigated the function of corticospinal tract in spinocerebellar ataxia 6 (SCA6) by measuring the central motor conduction time (CMCT). Motor evoked potentials (MEP) of tibialis anterior (TA) muscle were elicited by magnetic stimulation to motor cortex and spinal cord in 9 SCA6 patients and 10 normal height- and age-matched subjects. CMCT in lower limb of SCA6 patients (18.1 � 1.9 ms) was significantly prolonged than that of the normal subjects (15.0 � 1.0 ms) (p < 0:001). The prolonged CMCT was well correlated with the duration of disease (p ¼ 0:005), but MEP amplitudes and stimulation intensities were not significantly different. These results indicate that the corticospinal tract function is also impaired and correlate with the disease duration in SCA6. a 2003 Elsevier Ltd. All rights reserved.

We employed magnetic stimulation to study the masseter silent period (SP) in 16 healthy volunteers. Cutaneous perception threshold (CPT or 1 T) was determined. SP threshold was 30% M (maximal output) in each subject, equivalent to 1.5–3 T, and as intensity increased, SP durations prolonged. The correlation was higher with units of % M ( r = 0.89) than CPT ( r = 0.39). The recommended intensity was 60% M because of least variation of SP durations. Conclusively, magnetic stimulation is a new and painless method to study masseter SP. CPT is less effective in studying masseter SP with magnetic stimulation as the input effectiveness correlates best with % M rather than CPT.

We conducted a single-stage community-based study of dementia on all registered residents > or =65 years in age in a rural Chinese community. Neurologists conducted semistructured interviews and examined all participants; they also interviewed family members in cases where dementia was suspected. The diagnosis was made by consensus according to the criteria of the Diagnostic and Statistical Manual of Mental Disorders, 3rd ed, revised (DSM-III-R). Among the 2,055 contacted individuals, 1,736 (84.5%) participated in the study and 44 ( 13 men and 31 women) were diagnosed as having dementia, including 35 (80%) with probable Alzheimer disease (AD) and 3 (7%) with vascular dementia (VsD). The rates of dementia were 0.5% for ages 65-74 years, 2.9% for ages 75-84 years, and 12.0% for ages 85-101 years. The overall rate was 2.5% for age > or =65 years. After controlling for age, neither a lack of formal education nor being a woman was a risk factor for dementia. At 2-year follow-up, 30 of the 44 demented participants had died, yielding a 2-year survival rate of 32%. The present results corroborated our previous findings of lower prevalence rates of dementia among the Chinese than among Western populations, and both genetic and sociocultural factors may have contributed to the low rates. The lack of neuroradiological imaging studies in the present study may have contributed to the finding of an unusually low rate of VsD.

The diagnosis of Huntington's disease (HD) can be confirmed by detecting the expanded CAG repeat in the IT15 gene. Besides chorea, patients with HD may present with a variety of bizarre involuntary movements, resulting in confusion in making the diagnosis. Under such conditions, genetic analysis is the final confirmatory test. To determine if any patient with involuntary movements of undetermined etiology might be related to HD, we did genetic analysis on 22 patients and identified three with expanded CAG repeat. We could not obtain family history of HD in these patients due to adoption, early death of parents, or a vague history. All three patients were among the group with generalized chorea, but one had additional marked dystonic posturing. Together with four clinically recognizable HD patients, the relative frequency of HD among the 103 patients with choreiform movements in this hospital is 6.8%.

Clinical observations as well as electromyographic studies were carried out on 27 Taiwanese Chinese patients deemed to be suffering from a rare, unique and self-limiting variant of lower motor neuron disease affecting the upper limbs with juvenile onset and a marked male preponderance. The results agree with previous descriptions of the disease except for the higher incidence of triceps affection. The term 'juvenile lower cervical spinal muscular atrophy', which describes the disease more accurately, is being proposed. The geographic relevance is discussed.

We report the results of immunosuppressive treatment with intravenous cyclophosphamide in 12 patients with lower motor neuron syndrome and elevated titers of serum autoantibodies to GM1 ganglioside. All patients had lower motor neuron dysfunction including proximal or distal weakness, fasciculation and muscle atrophy, but no upper motor neuron dysfunction such as hyperreflexia, spasticity or Babinski's sign. Electrophysiological studies revealed no evidence of conduction block, but EMG findings of acute or chronic denervation in the limbs were present. Serum biochemistry and immunological studies were negative for M protein. After a 6-month follow-up, despite a fall in antibody titer, there was no significant clinical improvement in any of the patients.