Neurological research
-
Neurological research · Jan 2001
Case ReportsMagnetoencephalographic investigation of somatosensory homunculus in patients with peri-Rolandic tumors.
In order to investigate functional topography of the hand somatosensory cortex in five patients with peri-Rolandic tumors (four frontal lobes and one parietal lobe), we recorded somatosensory evoked fields (SEFs) using magnetoencephalography (MEG) after stimulation of the median nerve (MN) and the five digits. The results obtained were compared with those of five normal healthy subjects. In all five patients, SEFs following MN and digit stimulation showed the previously described respective N20m and N22m components of primary sensory response. ⋯ The cortical representations of the hand were identical to those of normal subjects, arranging in an orderly somatotopic way from lateral inferior to medial superior in the sequence thumb, MN, index, middle, ring, and little fingers. This sensory homunculus was confirmed by cortical recording of the somatosensory evoked potentials (SEPs) at the time of surgery. Thus, we demonstrate that SEFs, recorded on MEG in conjunction with source localization techniques, are useful to non-invasively investigate the functional topography of the human hand somatosensory cortex in pathological conditions.
-
Neurological research · Oct 2000
Acute and late changes in N-acetyl-aspartate following diffuse axonal injury in rats: an MRI spectroscopy and microdialysis study.
N-acetyl-aspartate (NAA) measured by proton nuclear magnetic resonance spectroscopy (1H-NMR) has been used as a marker of neuronal injury in many cerebral pathologies. Therefore, we evaluate the roles of microdialysis vs. 1H-NMR as techniques to assess NAA (NAAd; NAA/Creatine ratio) in the living brain, and compare the results with whole brain NAA (NAAw), analyzed by HPLC after diffuse traumatic brain injury (TBI). Acute (4 h post-injury survival) and late (48 h survival) changes were studied in a sham-operated group (Sham, n = 4), and two injured groups (TBI/4 h, n = 8; TBI/48 h, n = 7). ⋯ Diffuse TBI did not produce long-term changes in NAA, assessed by three different methods. These results may indicate that NAA is not a sensitive marker of the severity of diffuse axonal damage. However, further studies are needed to evaluate whether confounding factors such as microdialysis probe, voxel position and non-regional tissue homogenization might have influenced our data.
-
Neurological research · Sep 2000
Endoscopic carpal tunnel release surgery: report of patient satisfaction.
Recently, a trend has developed to use an endoscope to achieve carpal tunnel release. Proponents of the endoscopic technique believe it has benefits to patients that include minimal incision, minimal pain and scarring, a shortened recovery period and a high level of patient satisfaction. To test these beliefs, a retrospective analysis of the first 42 cases that were done between May 1997 and June 1998 was completed. ⋯ No recurrent hematoma, infection, or structure injury was reported. Endoscopic carpal tunnel release can be done safely and effectively with excellent self-reports of patient satisfaction. Reduced recovery period and hospitalization with minimal tissue violation and incisional pain can be expected.
-
Neurological research · Sep 2000
Prevention of cerebral vasospasm by nicardipine prolonged-release implants in dogs.
The purpose of this study was to determine the efficacy of nicardipine prolonged-release implants for preventing vasospasm in a canine SAH model in a dose-escalating placebo-controlled blind fashion. Drug-release kinetics of copoly(lactic/glycolic acid) pellet containing nicardipine were evaluated in vitro. In vivo, 18 dogs were randomly assigned to one of three groups, i.e. placebo, low-dose (0.8 mg), or high-dose (8 mg) nicardipine. ⋯ The average percent reductions of vessel diameters in the middle cerebral artery on Day 7 were 43%, 14% and 7% in the placebo, low-dose, and high-dose groups, respectively (p = 0.0319). The mean concentration of nicardipine in the clots on Day 14 was 9.7 x 10(-7) mol-1 l-1 and 5.1 x 10(-6) mol-1 l-1 in the low-dose and high-dose group, respectively. This drug delivery system prevented vasospasm in dogs significantly even at low dose, while maintaining an appropriate concentration of nicardipine in the clot adjacent to the arteries.
-
Neurological research · Jul 2000
Comparative StudyLong latency response of the mentalis muscle following transcranial magnetic stimulation with a circular coil in normal subjects.
Short latency response (SLR), middle latency response and long latency response (LLR) are elicited in facial muscles by transcranial magnetic stimulation. Although it has been said that the LLRs are elicited by the trigeminal nerve stimulation, a trigeminofacial reflex is recorded easily in normal subjects by the electrical stimulation in orbicularis oculi muscles as a blind reflex, but a trigeminal-facial reflex recorded in orbicularis oris, namely a snout reflex, is more difficult to record in normal subjects. The aim of this study is to demonstrate the LLR of lower facial muscles (mentalis muscle) by the transcranial magnetic stimulation, using a circular coil. ⋯ At this time the LLR of the masseter muscle was not recorded following this transmagnetic stimulation. It was suggested that the LLR of the mentalis muscle is recorded by the transcranial magnetic stimulation of the trigeminal nerve with a circular coil. The ease and reliability of their recording make it possible to apply this LLR clinically as well as a blink reflex.