**Question:** A 5-year old child is assessed to have a developmental age of one year. His developmental quotient would be –

A. 80
B. 100
C. 100
D. 130

**Core Concept:**

Developmental quotient (DQ) is a measure of a child's cognitive development relative to their chronological age. It is calculated by dividing the mental age (MA) by the chronological age (CA) and multiplying by 100. DQ = (MA / CA) x 100.

**Why the Correct Answer is Right:**

In this case, the child's developmental age (MA) is 1 year, which is significantly lower than their chronological age (CA), i.e., 5 years. Therefore, the developmental quotient (DQ) would be high to compensate for this difference. The correct answer is D, as it represents a high DQ value (indicating delayed development) given the low MA (1 year) and high CA (5 years).

**Why Each Wrong Option is Incorrect:**

Option A (80) suggests a DQ value that is too low for a child with a MA of 1 year and CA of 5 years. Option B (100) suggests a DQ value that is too high, indicating normal development, which is not consistent with the child's delayed development. Option C (100) is also too high, as it suggests normal development, which is not consistent with the child's delayed development. Option D (130) is the only option that compensates for the significant difference between MA and CA, resulting in a high DQ value indicating delayed development.

**Clinical Pearl:**

Evaluation and intervention for developmental delays in children should be based on accurate assessments of their cognitive abilities, such as using the DQ calculation. A low DQ value can guide clinicians to address the child's developmental needs, such as providing targeted therapies or interventions to improve their growth and development.

**Correct Answer:** D. 130