"Isolation and detained" refers to his condition being held in jail. He is not in solitary confinement. Melzer arguent opinion that Assagne should should be released and not be detained.
>Although Mr. Assange is not being held in solitary confinement, Mr. Melzer said he was gravely concerned over the limited frequency and duration of lawyers’ visits and lack of access to case files, which make it impossible to prepare and adequate defense.
> «He continues to be detained under oppressive conditions of isolation and surveillance, not justified by his detention status,” said Melzer
Melzer fairly clearly states that he believes there is credible evidence that Assange has been subjected to psychological torture.