From the Guidelines
Evaluating deep tendon reflexes (DTR) as part of a neuro exam for ALS or MS is crucial to assess the integrity of the central nervous system, particularly the corticospinal tract.
Significance of DTR Evaluation
The presence or absence of these reflexes can help differentiate between upper motor neuron and lower motor neuron lesions.
- In ALS, the absence of deep tendon reflexes in the presence of upper motor neuron signs such as spasticity and hyperreflexia can indicate a mixed upper and lower motor neuron lesion 1.
- In MS, the evaluation of deep tendon reflexes can help identify areas of spinal cord involvement 1. A thorough evaluation of deep tendon reflexes, including the bicep, tricep, brachioradialis, knee jerk, and ankle jerk reflexes, can provide valuable information to support or rule out these diagnoses.
Clinical Application
According to the MAGNIMS consensus guidelines, MRI criteria for the diagnosis of multiple sclerosis should be applied for the evaluation of radiologically isolated syndromes (RIS) 1. However, a firm diagnosis of MS based on incidental findings on MRI alone, even with additional supportive findings on evoked potentials or typical CSF findings in the absence of MS-relevant clinical symptoms, is problematic. Therefore, evaluating deep tendon reflexes as part of a neuro exam for ALS or MS remains a cornerstone for diagnosis, particularly in the context of clinical presentation and other diagnostic criteria.
From the Research
Significance of Evaluating Deep Tendon Reflexes (DTR) in ALS or MS
- Evaluating DTR in ALS or MS is significant because it helps assess the integrity of the corticospinal tracts, which are affected in these diseases 2, 3, 4, 5, 6
- Studies have shown that diffusion tensor imaging (DTI) can detect changes in the diffusion characteristics of the white matter fibers in the posterior limb of the internal capsule, which can indicate damage to the corticospinal tracts in ALS 5
- The evaluation of DTR can also help differentiate between ALS patients with and without corticospinal tract hyperintensity, which can have implications for disease progression and treatment 3, 4
- Additionally, DTI metrics such as fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) can provide information on the microstructural changes in the corticospinal tracts, which can be used to monitor disease progression and response to treatment 2, 4, 5, 6
Clinical Relevance
- The evaluation of DTR in ALS or MS can provide valuable information on the clinical status of the patient, including the extent of upper motor neuron involvement and disease severity 2, 3, 4, 5, 6
- Studies have shown that DTI metrics can correlate with clinical measures of disease severity and upper motor neuron involvement, making them a useful tool for monitoring disease progression and response to treatment 2, 4, 5, 6
- The use of DTI to evaluate the corticospinal tracts can also help identify patients with a more aggressive disease course, which can inform treatment decisions 3, 4
Diagnostic Utility
- The evaluation of DTR in ALS or MS can have diagnostic utility, particularly when used in combination with other clinical and imaging modalities 3, 4, 5, 6
- Studies have shown that DTI metrics can differentiate between ALS patients and healthy controls, and can also differentiate between ALS patients with and without corticospinal tract hyperintensity 3, 4, 5, 6
- The use of machine learning approaches to analyze DTI metrics can also improve the diagnostic accuracy of ALS, making it a promising tool for clinical diagnosis 6