Is the diagnostic value of midbrain hyperechogenicity in ALS limited for discriminating key ALS differential diagnoses?
Midbrain hyperechogenicity is reproducibly found in ALS patients, but its diagnostic value for discriminating ALS from its key differentials is limited.
Using FEV1/FEV6 <LLN or GOLD stage 2-4 as the criterion for airflow obstruction reduces inconsistencies in the diagnosis of mild COPD. Further improvement could be obtained by defining a borderline zone around the LLN (e.g. plus or minus 0.6 SD), or repeating the test in patients with borderline results.