Abstract OBJECTIVE: Following a previous report [Bestmann et al. Clin Neurophysiol 2004;115:755-64] that pairs of subthreshold pulses of transcranial magnetic stimulation (TMS) can show temporal summation, we explored whether repeated application of pairs of stimulation could produce long-lasting after effects on the excitability of the human motor cortex. METHODS: Twelve healthy subjects received 25 min repetitive paired pulse magnetic stimulation (paired rTMS) given at a frequency of about 0.6 Hz over the left primary motor cortex (500 paired stimuli in total). The interval between the paired stimuli was 3 ms and the intensity of both stimuli was 80% of active motor threshold. The resting and active motor threshold, MEP recruitment curve, short interval intracortical inhibition (SICI) and facilitation, and the duration of the cortical silent period (SP) were tested for the right first interosseous muscle (FDI) before and two times after the end of 25 min paired rTMS. RESULTS: Prolonged subthreshold paired rTMS produced a significant decrease in excitability in the corticospinal projection to FDI: resting motor threshold was significantly increased and MEP recruitment was significantly decreased, SICI was significantly increased at 2 and 4 ms and the SP was significantly increased in duration. CONCLUSIONS: Prolonged low frequency paired rTMS at subthreshold intensity can modulate cortical excitability by producing inhibitory effects that outlast the period of stimulation.

Abstract BACKGROUND: Human milk provides infants with a full complement of all polyunsaturated fatty acids, including docosahexaenoic acid (DHA) and arachidonic acid (AA). Formula milks only contain the precursors of DHA, AA and linoleic acid, and hence formula-fed infants must synthesize their own DHA and AA. AIM: To evaluate the effect of feeding--whether breastfeeding or formula-feeding--in early infancy upon subsequent neurodevelopment and achievement of optimum brain function. SUBJECTS AND METHODS: The study included 53 normal, healthy infants (30 exclusively breastfed infants and 23 exclusively formula-fed infants) at the age of 1 y (+/-1 mo). Each infant was subjected to a full physical and neurological examination together with neurophysiological studies including flash visual evoked potential (FVEP), brainstem auditory evoked potential (BAEP) and somatosensory evoked potential (SSEP). RESULTS: There was significant prolongation of P100 wave latency of FVEP in formula-fed infants, together with significant prolongation of absolute latency of waves I, III and V of BAEP in formula-fed infants compared with breastfed infants. There was significant prolongation in inter-peak latencies between cortical and Erb's components in formula-fed infants compared with breastfed infants. CONCLUSION: We can conclude that VEP, BAEP and SSEP are more mature in breastfed infants relative to formula-fed infants at 1 y of age, and thus breast milk helps earlier development and maturation of some aspects of the nervous system than milk formulas.

Abstract BACKGROUND: Human milk provides infants with a full complement of all polyunsaturated fatty acids, including docosahexaenoic acid (DHA) and arachidonic acid (AA). Formula milks only contain the precursors of DHA, AA and linoleic acid, and hence formula-fed infants must synthesize their own DHA and AA. AIM: To evaluate the effect of feeding--whether breastfeeding or formula-feeding--in early infancy upon subsequent neurodevelopment and achievement of optimum brain function. SUBJECTS AND METHODS: The study included 53 normal, healthy infants (30 exclusively breastfed infants and 23 exclusively formula-fed infants) at the age of 1 y (+/-1 mo). Each infant was subjected to a full physical and neurological examination together with neurophysiological studies including flash visual evoked potential (FVEP), brainstem auditory evoked potential (BAEP) and somatosensory evoked potential (SSEP). RESULTS: There was significant prolongation of P100 wave latency of FVEP in formula-fed infants, together with significant prolongation of absolute latency of waves I, III and V of BAEP in formula-fed infants compared with breastfed infants. There was significant prolongation in inter-peak latencies between cortical and Erb's components in formula-fed infants compared with breastfed infants. CONCLUSION: We can conclude that VEP, BAEP and SSEP are more mature in breastfed infants relative to formula-fed infants at 1 y of age, and thus breast milk helps earlier development and maturation of some aspects of the nervous system than milk formulas.

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Abstract BACKGROUND AND OBJECTIVE: A single session of repetitive transcranial magnetic stimulation (rTMS) over motor cortex had been reported to produce short term relief of some types of chronic pain. The present study investigated whether five consecutive days of rTMS would lead to longer lasting pain relief in unilateral chronic intractable neuropathic pain. PATIENTS AND METHODS: Forty eight patients with therapy resistant chronic unilateral pain syndromes (24 each with trigeminal neuralgia (TGN) and post-stroke pain syndrome (PSP)) participated. Fourteen from each group received 10 minutes real rTMS over the hand area of motor cortex (20 Hz, 10x10 s trains, intensity 80% of motor threshold) every day for five consecutive days. The remaining patients received sham stimulation. Pain was assessed using a visual analogue scale (VAS) and the Leeds assessment of neuropathic symptoms and signs (LANSS) scale, before, after the first, fourth, and fifth sessions, and two weeks after the last session. RESULTS: No significant differences were found in basal pain ratings between patients receiving real- and sham-rTMS. However, a two factor ANOVA revealed a significant "+/- TMS" x "time" interaction indicating that real and sham rTMS had different effects on the VAS and LANSS scales. Post hoc testing showed that in both groups of patients, real-rTMS led to a greater improvement in scales than sham-rTMS, evident even two weeks after the end of the treatment. No patient experienced adverse effects. CONCLUSION: These results confirm that five daily sessions of rTMS over motor cortex can produce longlasting pain relief in patients with TGN or PSP.

Abstract BACKGROUND AND OBJECTIVE: A single session of repetitive transcranial magnetic stimulation (rTMS) over motor cortex had been reported to produce short term relief of some types of chronic pain. The present study investigated whether five consecutive days of rTMS would lead to longer lasting pain relief in unilateral chronic intractable neuropathic pain. PATIENTS AND METHODS: Forty eight patients with therapy resistant chronic unilateral pain syndromes (24 each with trigeminal neuralgia (TGN) and post-stroke pain syndrome (PSP)) participated. Fourteen from each group received 10 minutes real rTMS over the hand area of motor cortex (20 Hz, 10x10 s trains, intensity 80% of motor threshold) every day for five consecutive days. The remaining patients received sham stimulation. Pain was assessed using a visual analogue scale (VAS) and the Leeds assessment of neuropathic symptoms and signs (LANSS) scale, before, after the first, fourth, and fifth sessions, and two weeks after the last session. RESULTS: No significant differences were found in basal pain ratings between patients receiving real- and sham-rTMS. However, a two factor ANOVA revealed a significant "+/- TMS" x "time" interaction indicating that real and sham rTMS had different effects on the VAS and LANSS scales. Post hoc testing showed that in both groups of patients, real-rTMS led to a greater improvement in scales than sham-rTMS, evident even two weeks after the end of the treatment. No patient experienced adverse effects. CONCLUSION: These results confirm that five daily sessions of rTMS over motor cortex can produce longlasting pain relief in patients with TGN or PSP.

Abstract BACKGROUND AND OBJECTIVE: A single session of repetitive transcranial magnetic stimulation (rTMS) over motor cortex had been reported to produce short term relief of some types of chronic pain. The present study investigated whether five consecutive days of rTMS would lead to longer lasting pain relief in unilateral chronic intractable neuropathic pain. PATIENTS AND METHODS: Forty eight patients with therapy resistant chronic unilateral pain syndromes (24 each with trigeminal neuralgia (TGN) and post-stroke pain syndrome (PSP)) participated. Fourteen from each group received 10 minutes real rTMS over the hand area of motor cortex (20 Hz, 10x10 s trains, intensity 80% of motor threshold) every day for five consecutive days. The remaining patients received sham stimulation. Pain was assessed using a visual analogue scale (VAS) and the Leeds assessment of neuropathic symptoms and signs (LANSS) scale, before, after the first, fourth, and fifth sessions, and two weeks after the last session. RESULTS: No significant differences were found in basal pain ratings between patients receiving real- and sham-rTMS. However, a two factor ANOVA revealed a significant "+/- TMS" x "time" interaction indicating that real and sham rTMS had different effects on the VAS and LANSS scales. Post hoc testing showed that in both groups of patients, real-rTMS led to a greater improvement in scales than sham-rTMS, evident even two weeks after the end of the treatment. No patient experienced adverse effects. CONCLUSION: These results confirm that five daily sessions of rTMS over motor cortex can produce longlasting pain relief in patients with TGN or PSP.

Abstract The occurrence of dysarthria is not infrequent in stroke but little is known about its pathophysiology. The aims of the present study were to assess the central motor innervation of the tongue in normal adults using transcranial magnetic stimulation (TMS) and to compare this with that seen in stroke patients with or without dysarthria. The study included 46 patients with acute monohemispheric stroke due to occlusion of the territory of the middle cerebral artery as documented by CT brain scan (26 patients with dysarthria and 20 patients without dysarthria). Forty-five (age and sex matched) normal volunteers served as controls. Corticolingual pathways were assessed for each subject after TMS of each hemisphere. TMS over the motor cortex of healthy subjects elicited consistent ipsilateral and contralateral lingual responses. The ipsilateral response was usually smaller and approximately 73% of the amplitude of the contralateral response. The cross talk between the two halves of the tongue as estimated after unilateral electrical stimulation of hypoglossal nerve gave a contra/ipsi ratio of 36%, which was significantly smaller than the ratio seen after cortical stimulation (CL). For the patients, with or without dysarthria, motor evoked potential (MEP) latencies (ipsilateral and contralateral) were significantly prolonged after stimulation of affected hemisphere compared with the non-affected hemisphere or the control group (P 0.001). MEP amplitudes were significantly smaller in hemiplegic patients with dysarthria compared to patients without dysarthria. In patients without dysarthria stimulation of the unaffected hemisphere tended to evoke responses that were of similar size on both sides. There were no significant associations between neurophysiological parameters and side of infarction. We conclude that interruption of the corticolingual pathways is frequent in stroke patients with or without dysarthria. The ability of unaffected hemisphere to evoke responses in the side contralateral to the lesion may relate to the absence or presence of dysarthria.

Abstract Repetitive transcranial magnetic stimulation (rTMS) or sham stimulation was given over the motor cortex daily for 10 days to two randomly assigned groups of 26 patients with acute ischemic stroke. Patients otherwise continued their normal treatment. Disability scales measured before rTMS, at the end of the last rTMS session, and 10 days later showed that real rTMS improved patients' scores more than sham.