Arthropod-borne virus encephalitis
Avindra Nath, Joseph R. Berger in Clinical Neurovirology, 2020
Laboratory studies include CSF typical of viral infection with a mononuclear pleocytosis, and a moderate protein elevation [44]. A peripheral leukocytosis is more common than a leukopenia, although the WBC count may be normal. White cells may be found in the urine, in the absence of bacteriuria, with an elevated BUN and/or creatinine. Electromyographic abnormalities may be found compatible with lower motor neuron dysfunction [44]. A study of eleven patients from the 1995 Dallas epidemic found abnormal EEGs in all nine patients studied, including diffuse background slowing in 7 patients, status epilepticus (1 patient), and bilateral periodic lateralized epileptiform discharges (1 patient). CT scans revealed nonspecific findings such as atrophy. However, review of five MRI scans showed T2 weighted hyperintensity of the substantia nigra [46]. Presumptive viral diagnosis during the acute illness relies on IgM capture ELISA. However, verification requires assays such as serum neutralization because of cross-reactivity with closely related viruses [42]. Reverse transcriptase PCR has detected 10 gene copies per reaction and may be helpful for diagnosis [23]. Metagenomic next-generation sequencing has also detected the virus in a fatal case of meningoencephalitis [47].
Low Back Pain and Sciatica: Pathogenesis, Diagnosis and Nonoperative Treatment
Gary W. Jay in Practical Guide to Chronic Pain Syndromes, 2016
Lower motor neuron versus upper motor neuron syndromes and the level of spinal dysfunction should be identified by the examining physician. Rectal examination is indicated in patients when myelopathy, especially cauda equina syndrome, is of diagnostic concern. Tone of the anal sphincter and the presence or absence of anal wink should be correlated with motor, sensory, and reflex findings in these cases. In all spinal examinations, a general overview of the patient’s health must be confirmed by examination. Extremities affected by chronic pain may demonstrate abnormal skin with a rough, leathery texture or shiny skin with trophic changes including hair loss, edema, abnormal temperature, and discoloration (bluish, reddish, or brownish hues). These changes may infer the presence of chronic pain, sympathetic nervous system involvement, or vascular insufficiency. Knowledge of cardiovascular and peripheral vascular status obtained by examination is pivotal in cases of claudication or reduced exercise tolerance for determining a diagnostic and treatment plan (1) (Tables 2 and 3).
Electrical stimulation for bladder management
Jacques Corcos, David Ginsberg, Gilles Karsenty in Textbook of the Neurogenic Bladder, 2015
In the 1950s in Budapest, Professor Ferenc Katona picked up an old, long forgotten method by M.H. Saxtorph to treat children with spina bifida and neurogenic urinary retention.13 This method involves placement of a cathetermounted electrode to provide electrical stimulation from within the bladder vesicle. A large suprapubic electrode acts as the return electrode. In 1975, Katona postulated a theory about the reorganization of vegetative afferents involved in the bladder control during intravesical stimulation (IVES).14 Later this technique was used by other rehabilitation centers with mixed results.15 In 1992, Ebner et al. evaluated the working mechanism in cats and rats.16 The main conclusion of Ebner was that IVES activates directly the mechanoreceptor afferents in the bladder wall, which may elicit reflexive detrusor contractions. These mechanoreceptors should be responsible for providing the main motor drive through a positive feedback process during normal voiding (Figure 47.1). This theory postulates an important neurological prerequisite for successful stimulation: the spinal reflex pathways controlling micturition must be intact. If a spinal lesion disrupts these pathways or if a person has a lower motor neuron lesion, then this intervention may not work. In 1998, Kiss et al. emphasized the clinical value of cortically evoked potentials of the urothelium to prove the degree of the afferent lesion as a predictor for the outcome of IVES.17
Transcranial Direct Current Stimulation of Motor Cortex Enhances Spike Performances of Professional Female Volleyball Players
Published in Journal of Motor Behavior, 2023
Seung-Bo Park, Doug Hyun Han, Junggi Hong, Jea-Woog Lee
In another aspect, although electrical stimulation was applied to the specific cortical area of M1 induced by tDCS in the present study, it might have affected adjacent areas, resulting in a somewhat more widespread area of target stimulation. This means that the premotor cortex, complex system of interconnected frontal lobe areas anterior to the primary motor cortex, s mainly responsible for motor functions. The upper motor neurons in the premotor cortex regulates motor behavior via extensive reciprocal connections with the primary motor cortex and axons projecting through the corticobulbar and corticospinal pathways that affect local circuit and lower motor neurons of the spinal cord and brainstem (Purves et al., 2001). In particular, the left dorsal premotor cortex activity is associated with complex motor coordination performance, meaning that tDCS has potential to improve visuomotor coordination (Pavlova et al., 2014). According to Tzvi et al. (2022), the cerebellum plays an essential role in the process of visuomotor adaptation. They noted that interaction with cortical structures, especially the premotor cortex, contributed mainly to this process. The cerebellum plays a central role in coordinating voluntary movements and motor skills including balance, coordination, and posture (Manto et al., 2012). These relationships suggest that activation of the premotor cortex and its interactions with the cerebellum could enhance the process of motor coordination by tDCS (Kwon et al., 2015; Tzvi et al., 2022).
Variation in communication strategies in amyotrophic lateral sclerosis during a two-year follow-up
Published in Speech, Language and Hearing, 2018
Tanja Makkonen, Hanna Ruottinen, Anna-Maija Korpijaakko-Huuhka, Johanna Palmio
Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease which affects motor functions (Kiernan et al., 2011). In most cases the disease starts with a combination of upper and lower motor neuron symptoms in the limb, and in about one third of patients the disease starts with bulbar symptoms affecting speech function (Duffy, 2013; Kiernan et al., 2011). Lower motor neuron involvement leads to fasciculations and muscle weakness and wasting, while upper motor neuron manifestations include spasticity, weakness, and brisk deep tendon reflexes. Therefore, ALS patients will typically demonstrate a flaccid-spastic mixed dysarthria (Duffy, 2013). Progressive loss of motor speech function results in progressive loss of muscle strength and control, increased duration of movements and reduction in bulbar muscle movements (Shellikeri et al., 2016; Yunusova et al., 2016). A rapid change in speech production is possible (Nishio & Niimi, 2000; Turner et al., 2010; Watts & Vanryckeghem, 2001). As ALS progresses the ability to speak declines in nearly all patients irrespective of the initial type of the disease (Tomik & Guiloff, 2010). It is reported that dysarthria occurs in 80%–95% of persons with ALS at some point during the disease (Beukelman, Fager, & Nordness, 2011). Progressive dysarthria weakens the ability to meet daily communication needs using natural speech.
The Role of Primary Motor Cortex: More Than Movement Execution
Published in Journal of Motor Behavior, 2021
Sagarika Bhattacharjee, Rajan Kashyap, Turki Abualait, Shen-Hsing Annabel Chen, Woo-Kyoung Yoo, Shahid Bashir
Early investigation of the motor cortex in humans (Penfield & Boldrey, 1937; Woolsey, 1952) had functionally divided the motor cortex into two major areas: the primary motor cortex (M1) and premotor area (PMA; Fulton, 1935). M1 is located in the precentral gyrus of the frontal lobe that plays a crucial role in the execution of voluntary movements (Pearson, 2000). Histological examination of M1 has revealed the presence of giant pyramidal neurons called Betz cells. Betz cells are also known as upper motor neurons because they send axons to the lower motor neurons situated in the gray column of the spinal cord. The upper motor neuron contributes to the corticospinal pathway, whereas the lower motor neurons innervate the skeletal muscle fibers situated at the periphery (Porter & Lemon, 1993). With this structural construct, M1 is predominantly considered to only have a role in motor execution.
Related Knowledge Centers
- Brainstem
- Cranial Nerve Nucleus
- Motor Neuron
- Muscle
- Upper Motor Neuron
- Skeletal Muscle
- Muscle Cell
- Cranial Nerves
- Anterior Grey Column
- Ventral Root of Spinal Nerve