Decoración de aparatos ortopédicos inadecuados en TikZ

Question

Acabo de crear una imagen de TikZ y de alguna manera el delimitador en la esquina inferior derecha es demasiado ancho. El delimitador debe tener 3 cm de ancho. Colocando su centro en x=6.5 debería terminar en x=5 y x=8. Pero ese no es el caso y no encuentro el error.

MWE:

\documentclass[12pt,a4paper]{article}
\usepackage[latin1]{inputenc}
\usepackage{tikz}
\usetikzlibrary{matrix}

\begin{document}
\begin{tikzpicture}[yscale=0.75]
\draw[help lines] (-2,-2) grid (8,6);

\tikzstyle{every node}=[font=\small, sharp corners, thick]
\tikzset{inner sep=2pt}

\newcommand{\akut}[1]{(0,0) -- node [draw, fill=white] {#1} (1,1)}
\newcommand{\chronisch}[1]{(0,0) -- node [draw, fill=white] {#1} (2,1)}
\newcommand{\schleichend}[1]{(0,0) -- node [draw, fill=white] {#1} +(1,1)}
\newcommand{\Schub}[1]{++(0.5,1.25) node [above, draw] {#1} -- ++(0.5,-0.5)}
\newcommand{\Welle}{+(0,0) to [out=0,in=180] +(0.5,1) node [above, draw] {1991} to [out=0,in=180] +(+0.5,-1)}
\newcommand{\Outcome}[1]{+(3,0) node [midway, above=2pt, draw] {#1}}

\draw [-][very thick, rounded corners]  \akut{1990} -- \Schub{1991} -- \Schub{1992} -- \Schub{1995} -- \Schub{1996} -- \Outcome{1999--2009} ;
\node [draw] (x) at (9,0) {Zeit};
\node [draw,align=center] (y) at (0,7) {Symptom-\\schwere};
\draw [<->] [thick] (y) -- (0,0) -- (x);
\node [above, below delimiter=\}] at (0.5,0) {\parbox{1cm}{\color{white}{.}}};
\node [draw] at (0.5,-0.55) {Beginn};
\node [above, below delimiter=\}] at (3,0) {\parbox{4cm}{\color{white}{.}}};
\node [draw] at (3,-0.55) {9-j\"ahriger Verlauf};
\node [above, below delimiter=\}] at (6.5,0) {\parbox{3cm}{\color{white}{.}}};
\node [draw] at (6.5,-0.55) {Outcome};
\node [left=2pt, draw]at (0,2) {leicht};
\node [left=2pt, draw]at (0,4) {mittel};
\node [left=2pt, draw]at (0,6) {schwer};
\end{tikzpicture}
\end{document}

Ejemplo:

Answer 1

Reemplacé mi enfoque anterior con los delimitadores dibujándolos con coordenadas específicas y luego agregué un archivo node. El nuevo código se ve así:

\draw[decorate,decoration={brace,amplitude=3pt,mirror}] 
    (0,-1pt)  -- (1,-1pt) node [below=5pt, midway, draw] {Beginn}; 
\draw[decorate,decoration={brace,amplitude=3pt,mirror}] 
    (1,-1pt)  -- (5,-1pt) node [below=5pt, midway, draw] {9-j\"ahriger Verlauf}; 
\draw[decorate,decoration={brace,amplitude=3pt,mirror}] 
    (5,-1pt)  -- (8,-1pt) node [below=5pt, midway, draw] {Outcome}; 

MWE:

\documentclass[12pt,a4paper]{article}
\usepackage[latin1]{inputenc}
\usepackage{tikz}
\usetikzlibrary{arrows,decorations.pathreplacing}

\begin{document}
\begin{tikzpicture}[scale=1]
\draw[help lines] (-2,-2) grid (8,6);

\tikzstyle{every node}=[font=\small, sharp corners, thick]
\tikzset{inner sep=2pt}

\newcommand{\akut}[1]{(0,0) -- node [draw, fill=white] {#1} (1,1)}
\newcommand{\chronisch}[1]{(0,0) -- node [draw, fill=white] {#1} (2,1)}
\newcommand{\schleichend}[1]{(0,0) -- node [draw, fill=white] {#1} +(1,1)}
\newcommand{\Schub}[1]{++(0.5,1.25) node [above, draw] {#1} -- ++(0.5,-0.5)}
\newcommand{\Welle}[1]{++(0.5,1.25) node [above, draw] {#1} -- ++(0.5,-1.25)}
\newcommand{\Outcome}[1]{+(3,0) node [midway, above=2pt, draw] {#1}}

\draw [-][very thick, rounded corners]  \akut{1990} -- \Schub{1991} -- \Schub{1992} -- \Schub{1995} -- \Schub{1996} -- \Outcome{1999--2009} ;
\node [draw] (x) at (9,0) {Zeit};
\node [draw,align=center] (y) at (0,7) {Symptom-\\schwere};
\draw [<->] [thick] (y) -- (0,0) -- (x);

\draw[decorate,decoration={brace,amplitude=3pt,mirror}] 
    (0,-1pt)  -- (1,-1pt) node [below=5pt, midway, draw] {Beginn}; 
\draw[decorate,decoration={brace,amplitude=3pt,mirror}] 
    (1,-1pt)  -- (5,-1pt) node [below=5pt, midway, draw] {9-j\"ahriger Verlauf}; 
\draw[decorate,decoration={brace,amplitude=3pt,mirror}] 
    (5,-1pt)  -- (8,-1pt) node [below=5pt, midway, draw] {Outcome}; 

\node [above left=2pt, draw]at (0,0) {Heilung};
\node [left=2pt, draw]at (0,2) {leicht};
\node [left=2pt, draw]at (0,4) {mittel};
\node [left=2pt, draw]at (0,6) {schwer};

\end{tikzpicture}
\end{document}

Ejemplo