A Study of Psychomotor Speed and Visuomotor Coordination in Type 2 Diabetes Mellitus.

Corresponding Author:
Dr. Sandeep Alex,
#117-E/VII, Anaiah,
Whitefield Residence,
Kudamaloor, Kottayam-686017,
Kerala, India.
E-mail: drsandeepalex@yahoo.co.in

ABSTRACT

BACKGROUND

Diabetes mellitus (DM) affects nearly 20% individuals above 65 years of age. With increasing life expectancy around the world, the absolute number of patients with type 2 diabetes mellitus has seen an exponential increase. Not surprisingly, the macrovascular complications associated with diabetes attracted the attention of clinicians and researchers. However, the cognitive dysfunctions associated with diabetes are studied less. Now, emerging evidence indicates that type 2 diabetes mellitus adversely affects cognitive functions. The studies of cognitive dysfunctions in type 2 diabetes have shown mixed results, with some studies showing a global decline while others reporting more circumscribed deficits in cognitive functions. Against this backdrop, current study set out to determine the effect of type 2 DM on a set of cognitive functions namely attention, sequencing, visuomotor coordination, psychomotor speed and motor persistence. These cognitive functions were chosen because of the possibility that they are more vulnerable to the effects of type 2 DM on brain and are affected earlier.

METHODS

30 patients with type 2 DM were matched against 30 nondiabetic controls. The sample was matched for age, gender, education and socio-economic status. The tools used were Trail Making Test – Part B (TMT-B) and Digit Symbol Substitution Test (DSST). Data was analysed using Student’s t- test, Chi-square test, ANOVA and Mann Whitney U test.

RESULTS

The mean time taken measured in seconds by patients with type 2 diabetes on TMT-B was 264.16 while controls took 144.66 seconds. In DSST, Diabetics took mean time of 531.83 seconds while the control group took mean time of 285.83 seconds to perform the test. The difference between the two groups was very highly significant (p value 0.001). The mean number of errors made by the cases group in TMT-B was 6.86 while those made by the control group was 1.70. In DSST, the mean number of errors was 8.26 for diabetics and 2.40 for controls. Again, the difference in performance between the two groups was very highly significant (p value 0.001). In patients with diabetes, the duration of illness resulted in very highly significant difference in the time taken for completion and number of errors made in both TMT-B and DSST with people with greater than 10 years of type 2 DM performing poorly than those with less than 5 years of illness (p value 0.001).

CONCLUSIONS

Diabetics had significant cognitive dysfunctions in cognitive domains of attention, sequencing, visual search, visuomotor coordination, motor persistence and response speed with respect to normoglycaemic controls. Furthermore, these deficits increased with longer duration of diabetes and advancing age.

KEY WORDS

Cognitive Dysfunctions, Type 2 Diabetes Mellitus, HbA1c, TMT-B, DSS