Table 2.

Studies reporting the association of mild chronic hyponatremia and neurocognitive deficits

StudyType of StudyCohort SizeMean PNa ±SD (mEq/L)Neurocognitive Assessment ToolOutcomes of Hyponatremia
Renneboog et al. (18)Crossover16128±3Battery of attention testsbMedian latencies increased by 58 ms (P<0.001) and no. of errors increased 1.2-fold (P=0.001)
Gosch et al. (19)Retrospective case control258128±3.2MMSE and CCIn multivariate analyses, hyponatremia was a significant predictor for abnormal scores on the MMSE (P=0.04; OR, 1.96; 95% CI, 1.05 to 3.68) and CC (P=0.02; OR, 2.57; 95% CI, 1.19 to 5.55)
Gunathilake et al. (20)Prospective cohort2550135 versus 130aARCSScores were, on average, 4.67 units significantly lower (P=0.01)
  • PNa, plasma sodium concentration; MMSE, Mini-Mental State Examination; CC, Clock Completion test; ARCS, Audio Recording Cognitive Screening tool; OR, odds ratio; 95% CI, 95% confidence interval.

  • a Study compared patients with PNa of 135 versus 130 mEq/L. No mean PNa was provided.

  • b Visual Vigilance, Working Memory or Digit Span, Go/No Go, Intermodal Comparison, Divided Attention, and Phasic Alert.