Sonographic Phrenic Nerve Changes in Amyotrophic Lateral Sclerosis.

Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease that affects both the upper and lower motor neurons in the nervous system, causing muscle weakness and severe disability. The progressive course of the disease reduces the functional capacity of the affected patients, limits daily activities, and leads to complete dependence on caregivers, ultimately resulting in a fatal outcome. Respiratory dysfunction mostly occurs later in the disease and is associated with a worse prognosis. Forty-six participants were included in our study, with 23 patients in the ALS group and 23 individuals in the control group. The ultrasound examination of the phrenic nerve (PN) was performed by two authors using a high-resolution "Philips EPIQ 7" ultrasound machine with a linear 4-18 MHz transducer. Our study revealed that the phrenic nerve is significantly smaller on both sides in ALS patients compared to the control group (p < 0.001). Only one significant study on PN ultrasound in ALS, conducted in Japan, also showed significant results (p < 0.00001). These small studies are particularly promising, as they suggest that ultrasound findings could serve as an additional diagnostic tool for ALS.

Sarcoidosis-Associated Sensory Ganglionopathy and Harlequin Syndrome: A Case Report.

Background and Objectives: Sensory ganglionopathy is a rare neurological disorder caused by degeneration of the neurons composing the dorsal root ganglia. It manifests as various sensory disturbances in the trunk, proximal limbs, face, or mouth in a patchy and asymmetrical pattern. Harlequin syndrome is characterized by unilateral flushing and sweating of the face, neck, and upper chest, concurrent with contralateral anhidrosis. Here, we present and discuss a clinical case of sarcoidosis-associated ganglionopathy and Harlequin syndrome. Case presentation: A 31-year-old woman complained of burning pain in the right side of the upper chest and the feet. She also experienced episodes of intense flushing and sweating on the right side of her face, neck, and upper chest. Three years before these symptoms began, the patient was diagnosed with pulmonary sarcoidosis. On neurological examination, sensory disturbances were present. In the trunk, the patient reported pronounced hyperalgesia and allodynia in the upper part of the right chest and some patches on the right side of the upper back. In the extremities, hypoalgesia in the tips of the fingers and hyperalgesia in the feet were noted. An extensive diagnostic workup was performed to eliminate other possible causes of these disorders. A broad range of possible metabolic, immunological, and structural causes were ruled out. Thus, the final clinical diagnosis of sarcoidosis-induced sensory ganglionopathy, small-fiber neuropathy, and Harlequin syndrome was made. Initially, the patient was treated with pregabalin and amitriptyline, but the effect was inadequate for the ganglionopathy-induced pain. Therefore, therapeutic plasma exchange as an immune-modulating treatment was selected, leading to partial pain relief. Conclusions: This case report demonstrates the possible autoimmune origin of both sensory ganglionopathy and Harlequin syndrome. It suggests that an autoimmune etiology for these disorders should be considered and the diagnostic workup should include screening for the most common autoimmune conditions.

Combined tendon reflex and motor evoked potential recordings in amyotrophic lateral sclerosis.

OBJECTIVE: This retrospective (case-control) collaborative study evaluates tendon reflex recordings combined with transcranial magnetic stimulation motor evoked potentials recordings (T-MEPs) at lower limbs in amyotrophic lateral sclerosis (ALS). METHODS: T-MEPs were recorded in 97 ALS patients distinguished according to their patellar reflex briskness. Patients' electrophysiological data were compared with values measured in 60 control patients matched for age and height. Correlations studies between parameters or with some patients' clinical characteristics were also performed. RESULTS: The central motor conduction time yields the highest sensitivity (82%) and specificity (93%), allowing twice more upper motor neuron (UMN) dysfunction detection than clinical examination, and being more altered in late stages of the disease. The T response to MEP response amplitude ratio (T/MEP ar) is nearly as sensitive to detect ALS and better identifies abnormal hyperreflexia. It is not correlated with evolutive stage, contrarily to conduction time-related parameters. In addition, T-MEPs detect asymmetries escaping clinical examination. CONCLUSIONS: The corticospinal conduction to lower limbs is slowed in ALS. The T/MEP ar helps deciding when patellar reflexes are abnormal in a given patient suspected of ALS. SIGNIFICANCE: The T-MEP technique provide powerful electrophysiological biomarkers of UMN involvement in ALS. This simple and painless procedure introduces the clinically useful concept of electrophysiological hyperreflexia and might be expanded to future exploration of proximal upper limbs and bulbar territories.

A clinical study of corticospinal and peripheral conductions to proximal lower limb muscles.

OBJECTIVE: To investigate the clinical utility of the newly developed "quadriceps combined technique" (QCT), which provides a global evaluation of the central and peripheral conduction to the proximal muscles of lower limbs, in a variety of central and peripheral neurological disorders. METHODS: Using surface recordings from the vastus medialis of the quadriceps muscle, we analyzed amplitudes and latencies of M response, patellar T reflex and motor evoked potentials (MEPs) after transcranial magnetic stimulation. We studied 180 patients with disorders impairing proximal strength of one or both lower limbs and compared them with 100 controls reported previously. RESULTS: The best parameters to detect central motor disorders were the central motor conduction time, MEP/M amplitude, T/MEP amplitude and latency ratios, whereas peripheral motor conduction time (PMCT) was best to assess peripheral disorders. The best parameter to identify proximal peripheral disorder was PMCTprox, whereas for distal peripheral disorders M amplitude and T/MEP amplitude ratio were most discriminative. CONCLUSIONS: We report a simple, rapidly performed and well-tolerated method that improves proximal lower limbs evaluation, helps distinguishing pathologic from physiological brisk reflexes and provides clues for etiologic diagnosis. SIGNIFICANCE: The QCT is a sensitive and specific tool to investigate central and peripheral neurological disorders.

Electrophysiological evaluation of motor pathways to proximal lower limb muscles: a combined method and reference values.

OBJECTIVE: In contrast with their important functional and clinical role, motor pathways to proximal muscles of lower limbs are rarely investigated in clinical neurophysiology. We describe a method to evaluate central and peripheral pathways to these muscles and report reference values. METHODS: Recording of both quadriceps was performed in 100 subjects. We analyzed the maximal M response after electrical stimulation of the femoral nerve, the patellar T reflex and the motor evoked potential (MEP) after transcranial magnetic stimulation. We defined the central motor conduction time as the difference between the MEP latency and the peripheral motor conduction time, estimated as the half of the T latency minus 0.5ms. RESULTS: The mean MEP latency is 20.6ms (SD 1.99ms), central motor conduction time 10.1ms (SD 1.29ms), MEP/M amplitude ratio 60.0% (SD 15.75%). Normal limits according to height and age are provided for each parameter and for interside asymmetry. CONCLUSIONS: This method to investigate the central and peripheral motor pathways supplying the L2-L4 myotomes is simple, painless and rapidly performed. The T reflex provides additional information on the proximal sensory pathways. SIGNIFICANCE: This method will be useful in many clinical conditions.

Transcranial magnetic stimulation in clinical practice.

Transcranial magnetic stimulation allows a non-invasive and painless stimulation of the human brain and cranial nerves. The method is in use since 1985. Transcranial magnetic stimulation can use single stimuli, pairs of stimuli separated by different intervals (to the same or to several brain areas), or trains of repetitive stimuli at various frequencies. Single stimuli give rise to motor evoked potentials that have clinical use and serve diagnostic and prognostic purposes. Repetitive transcranial magnetic stimulation can modify excitability of cerebral cortex. Repetitive transcranial magnetic stimulation has opened a new field of investigation of the neural circuitry, and is developing into a therapeutic tool. This general review considers basic principles of transcranial magnetic stimulation, discusses methodological aspects and techniques, and analyses their utility in clinical practice.