Harding listed criteria for making the clinical diagnosis of Friedreich's ataxia. The author is from the Middlesex Hospital in London.
Key findings:
(1) onset at an age <= 25 years
(2) progressive and unremitting ataxia of the limbs
(3) progressive and unremitting ataxia in gait
(4) absence of knee and ankle jerks (lower limb areflexia)
Additional common findings (may have a delayed onset after 5+ years):
(1) dysarthria
(2) extensor plantar response (positive Babinski sign)
(3) loss of position and vibration sense
(4) small or absent action potentials in the upper limbs with a motor nerve conduction velocity > 40 meters per second
Variable findings:
(1) scoliosis
(2) cardiomyopathy
(3) pes cavus
(4) distal amyotrophy
(5) optic atrophy
(6) nystagmus
(7) deafness
(8) diabetes mellitus
