Bioelectrical impedance analysis to estimate one-repetition maximum measurement of muscle strength for leg press in healthy young adults.

Resistance training (RT) progress is determined by an individual's muscle strength, measured by one-repetition maximum (1RM). However, this evaluation is time-consuming and has some safety concerns. Bioelectrical impedance analysis (BIA) is a valid and easy-to-use method to assess skeletal muscle mass (SMM). Although BIA measurements are often correlated with muscle strength, few studies of 1RM for RT and BIA measurements are available. This observational study examined the relationship between 1RM and BIA measurements and developed BIA-based prediction models for 1RM. Thirty-five healthy young Japanese adults were included. SMM and the skeletal muscle mass index (SMI) were measured using the BIA device. In addition, dominant-leg 1RM was measured using a unilateral leg-press (LP) machine. The correlations between BIA measurements and 1RM were calculated, and simple regression analyses were performed to predict 1RM from the BIA variables. The results showed significant correlations between 1RM and dominant-leg SMM (R = 0.845, P = 0.0001) and SMI (R = 0.910, P = 0.0001). The prediction models for 1RM for LP derived from SMM of the dominant leg and SMI were Y = 8.21x + 8.77 (P = 0.0001), R2 = 0.73, and Y = 15.53x - 36.33 (P = 0.0001), R2 = 0.83, respectively. Our results indicated that BIA-based SMI might be used to predict 1RM for LP accurately.

Effects of peripheral nerve stimulation on paralysed upper limb functional recovery in chronic stroke patients undergoing low-frequency repetitive transcranial magnetic stimulation and occupational therapy: A pilot study.

OBJECTIVE: Upper limb paralysis, which is a sequela of stroke, limits patients' activities of daily living and lowers quality of life. The objective of this study was to examine the effects of peripheral nerve stimulation on hemiparetic upper limb functional recovery in chronic stroke patients undergoing low-frequency repetitive transcranial magnetic stimulation and occupational therapy. METHODS: The subjects were chronic stroke patients who participated in a two-week inpatient programme including repetitive transcranial magnetic stimulation and occupational therapy. There were two groups of patients: the peripheral nerve stimulation group (11 patients who underwent peripheral nerve stimulation) and the control group (11 patients who previously participated in the same inpatient programme but without peripheral nerve stimulation, selected via propensity score matching). The peripheral nerve stimulation group had 1 h of peripheral nerve stimulation on the median and ulnar nerves during occupational therapy. The outcome measures were the Wolf Motor Function Test, Fugl-Meyer Assessment, and Motor Activity Log. RESULTS: Wolf Motor Function Test, Fugl-Meyer Assessment, and Motor Activity Log showed significant improvement after the intervention in the peripheral nerve stimulation group. Particularly, the Fugl-Meyer Assessment hand score significantly improved in the peripheral nerve stimulation group compared to that in the control group (median change: 2 versus 0; p = 0.021, r = 0.49). CONCLUSION: The combined use of peripheral nerve stimulation with occupational therapy after repetitive transcranial magnetic stimulation may result in a better functional recovery of in hemiparetic upper limb. Peripheral nerve stimulation with stimulation above the sensory threshold and below the motor threshold is easy to combine with occupational therapy upper limb function training and is therefore clinically useful.

Discharge responses of the optic tract to flash stimuli in Parkinson's disease.

Dopamine has a significant role in retinal processing, and it has been demonstrated that retinal dopamine content is decreased in parkinsonian patients. We measured the latency of the evoked discharges in the optic tract (OT) to flash stimuli during stereotactic pallidal neurosurgery in 25 patients with Parkinson's disease (PD) (13 women and 12 men, age 38-78 years, unified Parkinson's disease rating scale (UPDRS) Motor Score in the Off state 11-54, Hoehn and Yahr stage in the Off state 1.5-5) and investigated the effects of age at surgery, disease duration, levodopa dose, and severity of parkinsonian symptoms on the latency. OT discharges were evoked by monocular flash stimuli delivered from a flashlight with a krypton bulb with a tungsten filament. The luminance at the eye measured ∼4 × 10(4) cd/m(2). The light wavelength of the stimulus was composed of a wide spectrum with its peak at around 800 nm or longer. The latency of OT discharges ranged 49-79 msec, and there was a significant positive correlation between the latencies of evoked activities in the OT to a flashlight and age (r = 0.59, P < 0.001, by Pearson correlation), but no correlation between the latency and the severity of parkinsonian symptoms and between the latency and duration of illness. These results indicate that the delay in visual processing and conduction at the level of the retina and the OT are substantially derived from age-related degenerative changes in the retina and visual pathway which are apparently unrelated to the striatal dopamine deficiency in PD.

ON and OFF channels in human retinal ganglion cells.

The ON and OFF channels are basic functional elements in parallel processing in the visual system in vertebrates including primates. We analysed the responses of the optic tract fibre activity in response to switching a flashlight on or off in 25 awake patients with Parkinson's disease who underwent stereotactic surgery targeting the internal globus pallidus. The responses were evoked in a darkened room by a light with a luminance of approximately 4 × 10(4) cd m(-2) at the eye and a wide-spectrum wavelength. Most of the responses at the light on event were excitatory (38 out of 41 sites, 93%). Thirty-five sites with increase in activity at the light on event showed reciprocal responses or no responses to light off, and these sites were classified as containing ON fibres. In single-fibre analysis, all of 14 ON fibres were recorded at the sites of multi-fibre excitatory responses. Six sites showed multi-fibre excitatory responses at the light off event; three sites showed sustained reduction in activity at the light on event, and these three sites were classified as containing OFF fibres. In single-fibre analysis, two OFF fibres were recorded at the sites of multi-fibre suppressive responses at the light on event, and the other two OFF fibres were recorded at the sites of multi-fibre excitatory responses at the light on event. We found that all excitatory responses to light on were transient, while all but one excitatory responses to light off were sustained. Reduction in activity tended to be smaller than increase in activity at the light on event. These results demonstrate that the ON and OFF channels, and their transient and sustained features function in visual processing in humans.

Classification of extracellularly recorded neurons by their discharge patterns and their correlates with intracellularly identified neuronal types in the frontal cortex of behaving monkeys.

Neurons in the cerebral cortex are not homogeneous. However, neuronal types have been ignored in most previous work studying neuronal processes in behaving monkeys. We propose a new method to identify neuronal types in extracellular recording studies of behaving monkeys. We classified neurons as either bursting or non-bursting, and then classified the bursting neurons into three types: (i) neurons displaying a burst of many spikes (maximum number of spikes within a burst; NSB max > or = 8) at a high discharge rate (maximum interspike interval; ISI max < 5 ms); (ii) neurons displaying a burst of fewer spikes (NSB max < or = 5) at a high discharge rate (ISI max < 5 ms); and (iii) neurons displaying a burst of a few spikes (NSB max < or = 7) at relatively long ISIs (ISI max > 5 ms). We found that the discharge patterns of the four groups corresponded to those of regular spiking (RS), fast spiking (FS), fast rhythmic bursting (FRB) and intrinsic bursting (IB) neurons demonstrated in intracellular recording studies using in vitro slice preparations, respectively. In addition, we examined correlations with the task events for neurons recorded in the frontal eye field and neuronal interactions for pairs of neurons recorded simultaneously from a single electrode. We found that they were substantially different between RS and FS types. These results suggest that neurons in the frontal cortex of behaving monkeys can be classified into four types based on their discharge patterns, and that these four types contribute differentially to cortical operations.

Autopsy case of opsoclonus-myoclonus-ataxia and cerebellar cognitive affective syndrome associated with small cell carcinoma of the lung.

We report an autopsy case of paraneoplastic opsoclonus-myoclonus-ataxia syndrome associated with small cell carcinoma of the lung. Chemotherapy and lung lobectomy resulted in complete tumor remission and disappearance of myoclonus. However, emotional and behavioral disturbances relapsed and remitted associated with exacerbation of truncal ataxia and ocular flutter, which responded favorably to prednisolone. At autopsy, after 2 years and 11 months of illness, there was no recurrence of cancer. Neuropathologically, only the cerebellum was affected, with diffuse loss of Purkinje cells and dentate neurons, suggesting that the paraneoplastic cerebellar involvement may be responsible for the cognitive affective symptoms in our patient.