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Masahiro Sonoo

Publications and source records attributed to Masahiro Sonoo.

6 recordsLinked to original sources
PubMed2003

Establishment of standard values for the latency, interval and amplitude parameters of tibial nerve somatosensory evoked potentials (SEPs).

OBJECTIVE: To establish standard values for tibial nerve somatosensory evoked potentials (SEPs). METHODS: We examined SEPs following left tibial nerve stimulation in 65 normal subjects of various ages, and performed multiple regression analysis using height, age, (age-20)(2) and gender as predictor variables. We objectively selected the latency or interval parameters with less intersubject variability as the standard parameters for evaluation. RESULTS: Among 3 cortical bipolar derivations investigated, the Cz'-Cc lead gave a more constant and stable P38 component than the Cz'-Fz or Ci-Cc lead. The latencies of the N8o (N8 onset) of the popliteal potential, P15 (P15 peak) in the contralateral iliac crest-ipsilateral greater trochanter lead, N21, N30 and P38o/P38 in the Cz'-Cc lead, as well as the intervals between these components were selected as standard parameters. P15 was easily identified in all of the subjects and is expected to be a new parameter to evaluate the proximal segment of the tibial nerve. The amplitudes of P15 and the other components were also evaluated. We present nomograms for the normal limit values of each parameter. CONCLUSIONS: We present a thorough set of standard values for tibial SEPs where the subject factors were fully considered, and which is easily applicable to clinical practice.

Adult↗
PubMed2002

New attempts to quantify concentric needle electromyography.

Quantitative motor unit potential (MUP) analysis, which is a leading method of quantitative evaluation of concentric needle electromyography, has several inherent limitations. First, the most essential features of neurogenic or myogenic changes manifest as recruitment abnormalities, rather than as changes in MUP morphology. Second, two factors related to MUP sampling, focusing and level of contraction, greatly influence the parameters of sampled MUPs. Third, the MUP duration, considered to be the cardinal parameter in MUP analysis, has several drawbacks, including low stability and low discriminant sensitivity. We developed a new MUP parameter, the size index (SI), which is calculated from the MUP amplitude and area/amplitude ratio (thickness). The SI remained almost constant during electrode movements, as demonstrated by manual scanning of MUPs. It is a stable and robust parameter and achieved an extremely high ability to discriminate between normal and large neurogenic MUPs. It identifies features related to the sound produced by the MUP on the audio monitor, which is often used by trained electromyographers for qualitative assessments of MUPs.

Electromyography↗
PubMed2002

[An adult case of Moyamoya disease presenting with transient hemichorea].

A 54-year-old woman presented choreic movements in left face and extremities for three months. Cerebral angiography revealed occlusions of bilateral internal carotid arteries (right: after the furcation of posterior communicating artery; left: after the furcation of opthalmic artery) and net-like collaterals around the basal ganglia region (Moyamoya vessels). Haloperidol rapidly resolved the choreic movements and no recurrence was observed. PET demonstrated misery perfusion at bilateral temporo-parietal cortices. Especially, right peri-sylvian region showed the most severe ischemia. MRI demonstrated no infarcts. Therefore, ischemia of the right striatum was suspected to be the cause of the left-sided hemichorea. Previously, Moyamoya disease presenting chorea was infrequently reported in young people of less than 20 years of age. This is the first report of the aged patient of Moyamoya disease presenting with hemichorea and severe misery perfusion.

Chorea↗