Surface EMG and Upper-Limb Rehabilitation

In rehabilitating hemiplegic patients, purposeful movements such as the opening and closing of hands are reported to be more effective than passive movement with an instrument. The authors of this chapter used surface electromyogram (surface EMG) signals as a way to convey the patient’s conscious ability to open and close their hands. The muscles in the forearm contract when the hand is closed or opened, which creates a simple signal that is comparatively easy to measure with surface EMG, a simple measuring device. The action potentials of the muscles involved in the opening-and-closing motions of hands were measured from several points in the forearm when those muscles contracted, and their distribution was analyzed. The purpose of this study is to develop a simple system to recognize the movement of a patient’s hand using measurements of EMG signals from only the most characteristic points on the forearm to replace similar, but more complex, research such as multi-channel measurement and wave analysis by FFT. The authors specified the optimum measuring points on the palm and dorsal sides of the forearm for the recognition of hand motion by the experimental system. This system successfully recognized hand motion through the analysis of the surface EMG signals measured from only two optimum points to allow arbitrary control of the rehabilitation device based on the recognition results.

Apraxia

Apraxia is the inability to perform skilled and/or learned movements, not explainable on the basis of more elemental abnormalities. There are several types of apraxia of which the most commonly recognized are (1) limb kinetic apraxia, the loss of hand and finger dexterity; (2) ideomotor apraxia, deficits in pantomiming tool use and gestures with temporal and spatial errors, but with knowledge of the tasks still present; (3) ideational apraxia, the failure to carry out a series of tasks using multiple objects for an intended purpose; and (4) conceptual apraxia, loss of tool knowledge, when tools and objects are used inappropriately. Apraxia can be a feature of both frontotemporal dementia and Alzheimer disease, and even a rare presenting manifestation of both. How sensitive apraxia measures would be in early detection is not well known.

Aß Monomer, Oligomer and Fibril in Alzheimer's Disease

Alzheimer’s disease (AD), the most prevalent disease of aged people, is a progressive neurodegenerative disorder with dementia. Amyloid-ß (also known as ß-protein and referred to here as Aß) is a well-established, seminal peptide in AD that is produced from the amyloid precursor protein (APP) by consecutive digestion with the ß secretase of BACE (beta-site amyloid cleaving enzyme) and gamma secretase of the presenilin complex. Abnormal cerebral accumulation of Abeta in the form of insoluble fibrils in senile plaques and cerebral amyloid angiopathy (CAA) is a neuropathological hallmark of AD. In contrast to insoluble fibrillary Aß, a soluble oligomeric complex, ADDL, consists of low-n oligomers of Aß, such as Aß*56. Despite their different names, it is currently proposed that oligomeric Aß is directly involved in synaptic toxicity and cognitive dysfunction in the early stages of AD. This chapter identifies a novel APP mutation (E693delta; referred to as the Osaka mutation) in a pedigree with probable AD, resulting in a variant Aß lacking glutamate at position 22. Based on theoretical predictions and in vitro studies on synthetic mutant Aß peptides, the mutated Aß peptide showed a unique and enhanced oligomerization activity without fibrillization. This was further confirmed by PiB-PET analysis on the proband patient. Collectively, the chapter concludes that the Osaka mutation is the first human evidence for the hypothesis that oligomeric Aß is involved in AD.

Location and Functional Definition of Human Visual Motion Organization Using Functional Magnetic Resonance Imaging

In humans, functional imaging studies have found a homolog of the macaque motion complex, MT+, which is suggested to contain both the middle temporal (MT) and medial superior temporal (MST) areas in the ascending limb of the inferior temporal sulcus. In the macaque, the motion-sensitive MT and MST areas are adjacent in the superior temporal sulcus. Electrophysiology has identified several motion-selective regions in the superior temporal sulcus (STS) of the macaque. Two of the best-studied areas include the MT and MST areas. The MT area has strong projections to the adjacent MST area and is typically subdivided into the dorsal (MSTd) and lateral (MSTl) subregions. While MT encodes the basic elements of motion, MST has higher-order motion-processing abilities and has been implicated in the perception of both object motion and self motion. The macaque MST area has been shown to have considerably larger receptive fields than the MT area. The receptive fields of MT cells typically extend only a few degrees into the ipsilateral visual field, while MST neurons have receptive fields that extend well into the ipsilateral visual field. This study tentatively identifies these subregions as the human homologs of the macaque MT and MST areas, respectively (Fig. 1). Putative human MT and MST areas were typically located on the posterior/ventral and anterior/dorsal banks of a dorsal/posterior limb of the inferior temporal sulcus. These locations are similar to their relative positions in the macaque superior temporal sulcus.

An International Investigation of Driver’s Licenses for Dementia Patients with Considerations of Their Social Circumstances

The brief results of an international investigation of traffic accidents among aging people based on databases published by public institutions are discussed in this chapter. The aging rate and the number of dementia patients increase with the average life expectancy when it is over 70 years. Currently, the number of traffic accidents among aging people is increasing. Policies preventing the renewal of driver’s licenses for aging people are implemented in several countries. However, communication with family and neighbors is effective in preventing aging people from being involved in traffic accidents while walking.

The Coimagination Method and its Evaluation via the Conversation Interactivity Measuring Method

The causes of dementia are divided into genetic factors and cognitive factors. To prevent dementia by reducing the cognitive factors, the authors of this chapter have developed the coimagination method to activate three cognitive functions that decline at an early stage of mild cognitive impairment (MCI): episodic memory, division of attention, and planning function. The coimagination method supports interactive conversation through expressing feelings about images according to a theme. Allocated time periods and turns for each participant are predetermined so that all participants play the roles of both speaker and listener. Measuring the interactivity of conversation qualitatively and quantitatively has been quite difficult, but conversation interactivity may indicate the intensity of cognitive activities. This paper proposes the conversation interactivity measuring method (CIMM) to measure the intensity of cognitive activities employed during conversation using the coimagination method.

A Method for Eliciting the Support Needs from People with Early-Stage Dementia for Maintaining Social Living

In the area of welfare engineering, various technological research and developmental efforts have been made to support people with dementia. However, it is not clear if these efforts are based on the real needs of these people. When providing support to people with dementia, it is essential to know exactly what their needs are. Nevertheless, it is not easy to obtain appropriate answers from these people by simply asking “How can we help you?” In addition, it is unlikely that answers from those people will cover all of their support needs. In this chapter, a new method based on the “Person-Centered Care” concept is proposed for eliciting the support needs from, and determining their priorities for people with early-stage dementia who are eager to maintain their social living despite coping with various difficulties. First, all of the actual and potential tasks of social living in their daily life are determined. Support needs are then extracted systematically from those tasks by paying attention to what factors are bothering these people or are confusing to them rather than directly asking the individuals what type of support they want or need. Finally, the support needs are prioritized by taking the degree of the individuals’ confusion and task frequency into consideration. When interviewing people with dementia, special care must be taken to ensure that the individuals who have memory impairment are not overburdened . In the proposed method, visual materials such as cards and boards with illustrations are utilized so that people with dementia can answer questions more easily. Some interviews were conducted based on the proposed method to confirm that support needs can be determined systematically from people with early-stage dementia.

A Log-linearized Viscoelastic Model for Measuring Changes in Vascular Impedance

This chapter proposes a new nonlinear model, called a log-linearized viscoelastic model, to estimate the dynamic characteristics of human arterial walls. The model employs mechanical impedance factors, including stiffness and viscosity, in beat-to-beat measured from biological signals such as arterial blood pressure and photoplethysmograms. The validity of the proposed method is determined by demonstrating how arterial wall impedance properties change during arm position testing in the vertical direction. The estimated stiffness indices are compared with those of the conventional linear model. Estimated impedance parameters with contribution ratios exceeding 0.97 were used for comparison. The results indicated that stiffness and viscosity decrease when the arm is raised and increase when it is lowered, in the same pattern as mean blood pressure. However, the changes seen in the proposed nonlinear viscoelastic parameter are smaller (P < 0.05) than those of the linear model. This result suggests that the proposed nonlinear arterial viscoelastic model is less affected by changes in mean intravascular pressure during arm position changes.

Development of Neurorehabilitation Techniques Using Transcranial Magnetic Stimulation with Voluntary Muscle Contraction

The objective of this study was to elucidate the mechanism of transcranial magnetic stimulation (TMS) with maximum voluntary muscle contraction (MVC) (used to facilitate motor neuron function), the effects of magnetic stimulation at the foramen magnum level with MVC were tested by recording motor evoked potentials (MEPs) and the maximum muscle force. In addition, changes in regional cerebral blood flow (rCBF) due to TMS to the motor cortex during MVC were assessed using near infrared spectroscopy (NIRS). Three MEPs in the first dorsal interosseus (FDI) muscle elicited by TMS to the motor cortex or foramen magnum stimulation were recorded before and then at 15 minutes intervals for 1 hour after 4 MVCs (while subjects maximally pinched a strain-gauge transducer for 2 seconds). Five healthy volunteers received TMS to the left motor cortex while maximally grasping a hand dynamometer for 2 seconds 3 times at 10-second intervals and then repeated TMS with MVC 4 times within 1 hour. Oxy-hemoglobin (Hb) and deoxy-Hb levels were recorded at 24 scalp sites using NIRS while subjects grasped a hand dynamometer with MVC for 5 seconds before and after TMS with MVC. Foramen magnum stimulation with MVC significantly decreased MEP amplitudes after TMS with MVC for 1 hour. Oxy-Hb concentration of the left M1, subtracting the right M1, tended to increase after TMS with MVC. The present results suggest that TMS during MVC induces increased cortical motor neuron excitability. However, further studies are needed to elucidate the mechanism of how TMS with MVC might modulate cortical neuron excitability.

Noninvasive Detection of Misfolded Proteins in the Brain Using [11C]BF-227 PET

Alzheimer’s disease (AD) and many other neurodegenerative disorders belong to the family of protein misfolding diseases. These diseases are characterized by the deposition of insoluble protein aggregates containing an enriched ß-sheet structure. To evaluate PET amyloid-imaging tracer [11C]BF-227 as an agent for in vivo detection of various kinds of misfolded protein, a [11C]BF-227 PET study was performed in patients with various protein misfolding diseases, including AD, frontotemporal dementia (FTD), dementia with Lewy bodies (DLB), sporadic Creutzfeldt-Jakob disease (sCJD) and Gerstmann-Sträussler-Scheinker disease (GSS). BF-227 binds to ß-amyloid fibrils with high affinity. Most of the AD patients showed prominent retention of [11C]BF-227 in the neocortex. In addition, neocortical retention of BF-227 was observed in the subjects with mild cognitive impairment who converted to AD during follow-up. DLB patients had elevated [11C]BF-227 uptake in the neocortex. However, FTD and sCJD patients showed no cortical retention of [11C]BF-227. Patients with multiple system atrophy had elevated BF-227 binding in the putamen. Finally, GSS patients had elevated BF-227 uptake in the cerebellum and other brain regions. This chapter confirms that BF-227 can selectively bind to a-synuclein and prion protein deposits using postmortem brain samples. Based on these findings, [11C]BF-227 is not necessarily specific for ß-amyloid in AD patients. However, this tracer could be used to detect various types of protein aggregates in the brain.