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Table 5 Diagnostic testing frequency and median time to diagnosis

From: Diagnosis pathway for patients with amyotrophic lateral sclerosis: retrospective analysis of the US Medicare longitudinal claims database

Diagnostic test Total ALS cohort* Limb-onset subgroup Bulbar-onset subgroup
  Percent with test Median time to diagnosis, years Percent with test Median time to diagnosis, years Percent with test Median time to diagnosis, years
Nerve conduction testing
  Sensory nerve conduction test 38 2.75 41 2.75 30 2.50
  Motor nerve conduction test with F-wave 26 2.75 30 2.75 18 0.25
  Motor nerve conduction test without F-wave 23 2.75 24 2.88 18 0.50
  Imaging studies  
  MRI of neck and spine without dye 25 2.50 29 2.75 15 2.50
  CT scans (head or brain) with/without contrast material 39 2.50 43 2.75 19 1.25
  MRI of brain with/without dye 28 2.75 29 2.75 28 0.25
  Electromyography  
  Limb electromyography (2 extremities and related paraspinal areas) 19 2.75 22 2.50 12 ND
  Limb electromyography (1 extremity and related paraspinal areas) 16 2.50 18 2.75 10 ND
Other
  Exam of throat and/or upper gastrointestinal tract 22 2.50 15 3.00 48 2.50
  1. ALS, amyotrophic lateral sclerosis; CT, computed tomography; MRI, magnetic resonance imaging, ND, not determined, frequency of testing < 15%.
  2. *n = 399.
  3. In the eight quarters before ALS diagnosis, not including the quarter of diagnosis.
  4. In the time to diagnosis cohort (n = 272).