Nerve and Retinal Changes in Experimental Diabetes
John H. McNeill in Experimental Models of Diabetes, 2018
Polyneuropathies can affect the sensory, motor, or autonomic nervous system. Acute sensory neuropathy clinically manifests as a painful condition with complete recovery. Proximal motor neuropathies, also known as amyotrophy, are manifested as acute onset of pain and weakness of proximal muscle. Chronic sensorimotor polyneuropathy is the most common type of neuropathy. It is manifested as progressive glove-and-stocking anesthesia, paresthesia, or hyperasthesia, with impaired balance, propioception, and vibration. Although motor weakness is not pronounced, wasting of small muscle and loss of reflex activity are also manifested. As a long-term effect, foot ulceration and neuropathic changes may develop. Electrophysiologically impaired nerve conduction velocity is a key feature. Autonomic neuropathy may produce bladder, bowel, or gastric motility problems and postural hypotension.5,6
Neuromuscular disorders
Ashley W. Blom, David Warwick, Michael R. Whitehouse in Apley and Solomon’s System of Orthopaedics and Trauma, 2017
The nerve under study (usually a mixed motor and sensory nerve) is stimulated electrically at an easily accessible subcutaneous site (e.g. the forearm or wrist for the median nerve or behind the medial malleolus for the posterior tibial nerve), until it propagates an action potential which travels to the innervated muscle where a surface electrode records the response (Figure 10.7). Measurements are displayed on an oscilloscope screen, the most informative being the time it takes in milliseconds (ms) for the impulse to reach the muscle, called the latency, and the magnitude of the response evoked in millivolts (mV), called the amplitude of the evoked compound muscle action potential (CMAP). By measuring the distance from the stimulating electrode to the recording electrode, and setting this against the latency, one can deduce the nerve conduction velocity (NCV) in metres per second between those two points (Figure 10.8).
Skeletal Muscle Damage and Recovery from Eccentric Contractions
Datta Sourya, Debasis Bagchi in Extreme and Rare Sports, 2019
It has been shown that ECCs cause histological damage in rats, not only in the myofibrils, the extracellular matrix, and the triads of the cytoplasmic membrane system (Piitulainen et al. 2008; Proske and Morgan 2001), but also in nerve fibers and cause thinning of myelin sheaths (Kouzaki et al. 2016). Kouzaki et al. (2016) reported that M-wave latency was delayed by 12% at 24 h and 24% at 48 h after 60 ECCs of the elbow flexors in women, which suggests musculocutaneous nerve impairment. However, a significant correlation was not observed between the delay in nerve conduction velocity and the decrease in muscle strength. Moreover, a study in which 60 isotonic ECCs were performed using a 40% MVC dumbbell demonstrated that the M-wave latency was delayed by 32% immediately after completion of the exercise (Ochi, Tsuchiya, and Yanagimoto 2017). However, in this study, the relationship between nerve conduction velocity and other muscle damage markers was not investigated. Thus, there are still several issues that need to be clarified with regard to the relationship between decreased nerve function due to ECCs and muscle damage. The studies on the effect of ECCs on nerve function are extremely limited and detailed studies using human subjects to investigate motor nerve conduction velocity are warranted. Moreover, investigations on sensory nerve function are necessary in the future.
Slow progression of amyotrophic lateral sclerosis in a Chinese patient carrying SOD1 p.S135T mutation
Published in Amyotrophic Lateral Sclerosis and Frontotemporal Degeneration, 2022
Hanhui Fu, Kang Zhang, Xunzhe Yang, Libo Li, Liying Cui
Physical examination revealed no signs of cognitive impairment or bulbar palsy. Prominent atrophy was observed in her four limbs, more severe in the first dorsal interosseous muscles bilaterally. The Medical Research Council (MRC) grade of her right limbs was 2–3 and the left side was 4. Tendon reflexes were not elicited and bilateral pathological reflections were absent. No sensation disturbance was found. Nerve conduction velocity was normal. Needle electromyogram (EMG) revealed fibrillation and fasciculation potentials, as well as signs of neurogenic impairments in the cervical, thoracic, and lumbosacral segments. Routine hematological examinations, cerebrospinal fluid testing, brain and spinal cord MRI were unremarkable. Considering the long survival time that is different from the classical ALS phenotype, we conducted whole-exome sequencing (WES) for the patient and her family members. A missense mutation SOD1 c.404G>C, p.S135T was detected in this patient, but not in any other family members. (Figure 1(A,B)).
A patient with macrodystrophia lipomatosa bilaterally affecting the entire upper extremity: reporting of a rare case and literature review
Published in Case Reports in Plastic Surgery and Hand Surgery, 2021
Kyoko Baba, Shinya Kashiwagi, Mitsuru Nemoto, Akira Takeda, Keizo Fukumoto, Eiju Uchinuma
Usually, MDL is diagnosed based on family history, physical findings, and results from diagnostic imaging [12]. The relatives of the patient with MDL show no congenital anomalies of the extremities because the disorder is nonhereditary in nature. Physical examination indicates the disproportional overgrowth of the extremities in both longitudinal axis and circumference. Diagnostic imaging includes radiography, ultrasonography, CT, and MRI [13]. Among imaging modalities, MRI has been well recognized for its usefulness in a number of case reports [14,15]. Imaging findings include the localized overgrowth of soft tissues (e.g. adipose tissue that is equivalent in signal intensity to normal tissue) and bone tissues, adipose infiltration in the nerves, and ankylosis [6,13]. In a patient who undergoes invasive treatment, furthermore, MDL may be diagnosed along with histopathological examination that demonstrates the presence of fiber-scattered adipose tissue in soft tissues including the nerves, bone marrow, and other tissues [2,12,13]. Furthermore, neurophysiological examination may be conducted additionally that measures nerve conduction velocity and detects reductions in motor and sensory conduction velocities, blocked or reduced segmental conduction, and other changes [6].
Impact of occupational lead exposure on nerve conduction study data
Published in International Journal of Neuroscience, 2022
Tülin Aktürk, Gülay Çeliker, Hikmet Saçmacı
Nerve conduction studies were performed by the same neurologist using Nihon Kohden EMG device (model MEB-9400K, Tokyo, Japan), according to standard techniques. The sweep speed was set at 1 ms per division. The filter settings used a 20–2000 Hz bandpass for the sensory nerve studies and a 2–10,000 Hz bandpass for the motor nerve studies. Bipolar surface electrode recordings were used for motor and sensory nerve studies. The ground electrode was properly placed between the stimulator and the recording electrode. The temperature of the upper and lower extremities was kept at 32 °C or above. The recordings were obtained by supramaximal stimulation. All nerve conduction studies were carried out in a warm room at 26–28 °C. Nerve conduction studies were performed unilaterally on the non-dominantly side for each subject. Three features were measured in the nerves: distal latency, amplitude and nerve conduction velocity.
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