Effects of ventricular shunt treatment of normal pressure hydrocephalus on psychological functions

A prospective trial for diagnosis, treatment and evaluation of normal pressure hydrocephalus (NPH) was carried out in 30 consecutive patients (12 women, 18 men, mean age: 61 years, range 21-80). The clinical diagnosis was based on the presence of one or more of the three clinical elements of NPH: gait disturbance, incontinence and mental deterioration as well as radiological criteria of ventricular enlargement. Preoperatively, physical and radiological investigations and psychological tests were routinely performed. Cognitive functions such as fluency, selective attention and motor speed were re-examined within 24 hours after spinal tap of 40-50 cc. of CSF. Results of shunting were confirmed by CT scans and evaluated by means of psychological tests at least 3 months postoperatively. Psychological tests included IQ tests and tests for memory, selective attention and motor speed. Results indicate that spinal tap had no predictive value for the results after shunting as far as psychological functions are concerned. Shunt treatment showed an effect on cognitive functions of distractibility of attention and motor speed, but not on intelligence of memory. Three patients deteriorated, eleven remained stable and sixteen showed significant improvement on psychological tests, mainly those for attention, motor speed and memory, but rarely did any improvement of intelligence occur.