The onset of paralysis (spastic paraparesis) is sudden and symmetrical and affects the legs more than the arms. The resulting disability is permanent but does not progress. Typically, a patient is standing and walking on the balls of the feet with rigid legs and often with ankle clonus.

•  William Howlett (2012). Neurology in Africa. pp. 246–248. ISBN 978-82-7453-085-0.

Initially, most patients experience generalized weakness during the first days and are bedridden for some days or weeks before trying to walk. Occasional blurred vision and/or speech difficulties typically clear during the first month, except in severely affected patients. Spasticity is present from the first day, without any initial phase of flaccidity. After the initial weeks of functional improvement, the spastic paraparesis remains stable for the rest of life. Some patients may experience an abrupt aggravating episode, e.g. a sudden and permanent worsening of the spastic paraparesis. Such episodes are identical to the initial onset and can therefore be interpreted as a second onset.^{[citation needed]}

• World Health Organization (1996). “Konzo, a distinct type of upper motor neuron disease” (PDF). Weekly Epidemiological Record (in English and French). Geneva. 71: 225–232.
• Tylleskär T, et al. (1997). “Konzo – the walk of the camelion”. YouTube (8 minutes film). Archived from the original on 2021-12-15.

The severity of konzo varies; cases range from only hyperreflexia in the lower limbs to a severely disabled patient with spastic paraparesis, associated weakness of the trunk and arms, impaired eye movements, speech and possibly visual impairment. Although the severity varies from patient to patient, the longest upper motor neurons are invariably more affected than the shorter ones. Thus, a konzo patient with speech impairment always shows severe symptoms in the legs and arms.^{[citation needed]}

Recently, neuropsychological effects of konzo have been described from DR Congo.^{[clarification needed]}

• Boivin MJ, Okitundu D, Bumoko GMM, Sombo MT, Mumba D, Tylleskar T, Page CF, Tamfum Muyembe JJ, Tshala-Katumbay D. (2013). “Neuropsychological effects of konzo: a neuromotor disease associated with poorly processed cassava”. Pediatrics. 131 (4): e1231–e1239. doi:10.1542/peds.2012-3011. PMC 3608487. PMID 23530166.