Investigation of the relationship between upper extremity lateralization and dual task cost in ındividuals with hemiplegic cerebral palsy

Introduction
This study aims to investigate the relationship between upper extremity lateralization and dual-task cost in individuals with Hemiplegic Cerebral Palsy (HCP). This is a new and unknown issue in Cerebral Palsy.

Material and methods
The descriptive and cross-sectional study was conducted with 63 individuals with Hemiplegic Cerebral Palsy (n = 40) and typically developing peers (n = 23) between the ages of 7-17 years old. A pre-assessment was performed with the Gross Motor Function Classification System, Manual Ability Classification System, and Communication Function Classification System of the individuals with HCP. Left-right judgement was assessed by the laterality judgement task; manual ability was evaluated with the Nine Hole Peg Test (NHPT). While functional tests included upper extremity functional tests, and dualtask interferences of this test and the NHPT was also assessed.

Results
A significant difference was found between the HCP group and the typically developing group in lateralization accuracy and dual-task cost (p < 0.05). It was found that the relationship between lateralization response time and dominant cognitive NHPT dual-task cost (r = 0.327, p = 0.040). The relationship was found between lateralization accuracy and dominant cognitive NHPT dual-task cost, and lateralization response time and non-dominant motor NHPT dual-task cost (r = -0.360, p = 0.023; r = 0.312, p = 0.050, respectively).

Conclusions
Individuals with HCP have difficulty with dual tasks compared to typically developing peers. There is a relationship between upper extremity lateralization and dual-task cost in individuals with HCP. This can be a significant point for designing more effective intervention approaches on upper extremity lateralization and dual-task individuals with HCP.