Coming from Terry Kinney, a co-founder of Chicago's estimable Steppenwolf Theatre troupe, Diminished Capacity is an example of American independent cinema at its slackest, most predictably sentimental. Matthew Broderick plays a Chicago journalist suffering from the traumatic after-effects of concussion, the symptoms of which resemble premature senility, returning to his Missouri hometown to care for his eccentric uncle (Alan Alda) who has early Alzheimer's.
The uncle has rigged a typewriter on a jetty so that fish can write random poetry. He also cherishes a rare baseball card that's possibly worth several hundred thousand dollars. Nephew, uncle and several other Missourians head to a sports memorabilia convention to have it valued and sold. Achingly slow, painfully whimsical, the film comes to life only when a pair of contrasted memorabilia dealers – one crazy (Bobby Cannavale), the other moderately sane (Dylan Baker) – are present.